WO2007066695A1

WO2007066695A1 - Direction calculation device, direction calculation method, direction calculation program, and recording medium

Info

Publication number: WO2007066695A1
Application number: PCT/JP2006/324374
Authority: WO
Inventors: Toshiharu Baba
Original assignee: Pioneer Corporation
Priority date: 2005-12-08
Filing date: 2006-12-06
Publication date: 2007-06-14
Also published as: JPWO2007066695A1

Abstract

A direction calculation device (100) includes: a direction calculation unit (101) for calculating a sensor direction and a GPS direction; a recording unit (102) for accumulating/recording a positive change amount or a negative change amount of the sensor direction change amount for each predetermined sampling cycle; a detection unit (103) for detecting the sampling time when the positive or negative change amount is stabilized and begins to be continuously recorded for a predetermined number of times as a first time and detecting the sampling time when the accumulated values of the positive change amount and the negative change amount from the first time have become equal as a second time; a comparison unit (104) for comparing the GPS directions and the sensor directions at the first time and the second time; a correction amount deciding unit (105) for deciding a correction amount by using the comparison result; and a corrected direction calculating unit (106) for calculating a corrected sensor direction by using the correction amount.

Description

Specification

Direction calculation device, direction calculation method, direction calculation program, and recording medium Technical field

[0001] The present invention relates to an azimuth calculation device, an azimuth calculation method, an azimuth calculation program, and a recording medium that automatically correct a detection error of an angular velocity sensor. However, the use of this invention is not limited to the above-described direction calculation device, direction calculation method, direction calculation program, and recording medium.

Background technology

[0002] Navigation devices installed in vehicles and the like use angular velocity sensors to determine the direction of the own vehicle. The heading is determined by calculating the angular velocity and turning direction of the vehicle using the output value from the angular velocity sensor. At this time, the sensitivity characteristics of the angular velocity sensor may differ depending on the turning direction of the vehicle, so it is necessary to correct the detection error.

[0003] Conventionally, with angular velocity sensors, the above-mentioned detection errors are considered to be within the allowable range and used as is, or correction processing is performed each time the navigation device is used, or if the error occurs during detection. It was used by processing it to make it smaller. The correction process involves technology that actually drives the vehicle left and right at a predetermined angle, detects the difference in sensitivity in the direction of the turn, and reflects this in the detection of the angular velocity sensor, and sets different correction coefficients depending on the direction of the turn. A navigation device is disclosed that has a correction function that eliminates the influence of the bending direction on the sensitivity characteristics of an angular velocity sensor (for example, see Patent Document 1 below).

[0004] Patent document 1: Japanese Patent Application Laid-Open No. 8-304090

Disclosure of invention

Problems that the invention seeks to solve

[0005] It is a burden for the user to perform the above-described correction process every time he or she uses the navigation device to accurately measure the orientation. Furthermore, even if the technology described in Patent Document 1 is used, the sensitivity difference (gain An example of this problem is that the direction cannot be determined more accurately than a predetermined accuracy because the effects of detection errors are different and the influence of detection errors cannot be completely removed.

Means to solve problems

[0006] In order to solve the above-mentioned problems and achieve the purpose, the azimuth calculation device according to the invention of claim 1 calculates the sensor azimuth using the output value of the angular velocity sensor, and calculates the GPS azimuth based on the GPS signal. and an azimuth calculation means for calculating the change in the output value of the angular velocity sensor. ); a detection means for detecting two sampling times that satisfy a predetermined condition based on the sampling period of the recording means; a comparison means that performs one or more of the following: a comparison of the azimuth values calculated by the azimuth calculation means; or a comparison of cumulative values of positive and negative changes recorded by the recording means; correction amount determining means for determining a correction amount for correcting the detection error of the sensor orientation based on a comparison result in the means; The present invention is characterized by comprising a corrected azimuth calculation means for calculating a corrected azimuth in which a detection error of the calculated sensor azimuth is corrected.

[0007] Further, the azimuth calculation device according to the invention of claim 2 includes: azimuth calculation means for calculating the sensor azimuth using the output value of the angular velocity sensor and calculating the GPS azimuth based on the GPS signal; and the angular velocity sensor. a recording means for recording the amount of change in the output value of the output value as a value larger than a predetermined reference value (a positive amount of change) and a value smaller than a predetermined reference value (a negative amount of change) at each predetermined sampling period; , when a positive or negative amount of change is continuously recorded by the recording means for a predetermined number of sampling times, a sampling time (first time) at which the recording is started is detected, and the first time is detected. A value obtained by accumulating the amount of positive change recorded by the recording means (positive cumulative value) is compared with a value obtained by accumulating the amount of negative change (negative cumulative value), and the value obtained by accumulating the amount of negative change is compared with the positive cumulative value. a detection means for detecting a sampling time (second time) at which the negative cumulative value becomes equal; a value of the GPS direction detected by the detection means at the first time; and a value of the GPS direction at the second time; When comparing with the GPS direction value a comparison means for comparing the sensor orientation value at the first time with the sensor orientation value at the second time; a correction amount determining means for determining a correction amount for correcting a detection error of the sensor orientation based on a direction corresponding to a change amount determined by the sensor; The present invention is characterized by comprising a corrected azimuth calculating means for calculating a corrected azimuth by correcting the detection error of the sensor azimuth calculated by the means.

[0008] Further, the azimuth calculation device according to the invention of claim 4 includes: azimuth calculation means that calculates the sensor azimuth using the output value of the angular velocity sensor and calculates the GPS azimuth based on the GPS signal; and the angular velocity sensor. a recording means for recording the amount of change in the output value of the output value as a value larger than a predetermined reference value (a positive amount of change) and a value smaller than a predetermined reference value (a negative amount of change) at each predetermined sampling period; , when a positive amount of change or a negative amount of change is continuously recorded by the recording means for a predetermined number of sampling times, a sampling time (first time) at which the recording is started is detected, and the direction is detected. The calculation means includes a detection means for detecting a sampling time (second time) at which the sensor orientation is calculated, such as the sensor orientation at the first time, and a GPS orientation at the first time detected by the detection means. and the value of the GPS direction at the second time, and also compare the value of the positive change between the first time and the second time (positive cumulative value). , a comparison means for comparing the accumulated negative amount of change (negative cumulative value), and based on the comparison result by the comparison means, corresponds to the amount of change continuously recorded by the recording means. a correction amount determining means for determining a correction amount for correcting the detection error of the sensor azimuth based on the direction in which the sensor azimuth is detected; and a correction amount determining means for determining the correction amount determined by the correction amount determining means. The present invention is characterized by comprising a corrected azimuth calculation means for calculating a corrected azimuth in which a detection error of the sensor azimuth is corrected.

[0009] Further, the azimuth calculation method according to the invention of claim 7 includes a azimuth calculation step of calculating a sensor azimuth using an output value of an angular velocity sensor and calculating a GPS azimuth based on a GPS signal; The amount of change in the output value of is calculated as a value larger than a predetermined reference value (positive change amount) and a value smaller than the predetermined reference value (negative change amount) at each predetermined sampling period. a recording step of recording, a detection step of detecting two sampling times that satisfy a predetermined condition based on the sampling period in the recording step, and a direction calculation means at the two sampling times detected by the detection step. A comparison step of comparing one or more of the calculated azimuth values or the cumulative values of positive and negative changes recorded in the recording step, and based on the comparison results of the comparison means!/ , a correction amount determination step for determining a correction amount for correcting a detection error in the sensor orientation; and a sensor orientation calculated in the orientation calculation step using the correction amount selected in the correction amount determination step. The method is characterized in that it includes a corrected direction calculation step of calculating a corrected direction in which the detection error of the detected direction is corrected.

[0010] Further, the azimuth calculation method according to the invention of claim 8 includes a azimuth calculation step of calculating a sensor azimuth using an output value of an angular velocity sensor and calculating a GPS azimuth based on a GPS signal; The amount of change in the output value of is greater than a predetermined reference value at each predetermined sampling period.

, a recording step in which the positive or negative amount of change is recorded as a value (negative amount of change), and when a positive or negative amount of change is continuously recorded a predetermined sampling number of times in the recording step, the sampling time (when the recording started) is recorded. The first time) is detected, and a value (positive cumulative value) that accumulates the positive changes recorded by the recording means from the first time and a value (negative cumulative value) that accumulates the negative changes recorded by the recording means from the first time are detected. a detection step of detecting a sampling time (second time) at which the positive cumulative value and the negative cumulative value become equal; and a first sampling time detected by the detecting step. The value of the GPS direction at the time and the value of the GPS direction at the second time are compared, and the value of the sensor direction at the first time is compared with the value of the sensor direction at the second time. and a correction amount for determining a correction amount for correcting the detection error of the sensor orientation based on the comparison result of the comparison step, with reference to the direction corresponding to the amount of change continuously recorded in the recording step. a determining step; and a corrected azimuth calculating step of calculating a corrected azimuth in which the detection error of the sensor azimuth calculated in the azimuth calculating step is corrected using the correction amount selected in the correction amount determining step. It is characterized by containing.

[0011] Further, the azimuth calculation method according to the invention of claim 9 uses the output value of the angular velocity sensor. An azimuth calculation process of calculating the sensor azimuth and calculating the GPS azimuth based on the GPS signal, and calculating the amount of change in the output value of the angular velocity sensor to a value larger than a predetermined reference value at each predetermined sampling period. (positive amount of change) and

, a recording process in which the value (negative change amount) is recorded, respectively, and a sampling process in which the recording is started when a positive change amount or a negative change amount is continuously recorded for a predetermined number of sampling times in the recording process. a detection step of detecting a time (first time) and, in the azimuth calculation means, detecting a sampling time (second time) at which the sensor azimuth was calculated, such as the sensor azimuth at the first time; , the value of the GPS direction at the first time detected by the detection step and the value of the GPS direction at the second time are compared, and the value of the GPS direction between the first time and the second time is compared. Based on the comparison process of comparing the accumulated positive amount of change (positive cumulative value) and the accumulated value of negative amount of change (negative cumulative value), and the comparison result from the comparison process. , a correction amount determining step for determining a correction amount for correcting the detection error of the sensor orientation based on a direction corresponding to the amount of change continuously recorded in the recording step; The present invention is characterized by comprising a corrected azimuth calculation step of calculating a corrected azimuth in which a detection error of the sensor azimuth calculated in the azimuth calculation step is corrected using the correction amount obtained in the azimuth calculation step.

[0012] Furthermore, the orientation calculation program according to claim 10 is characterized by causing a computer to execute the orientation calculation method according to any one of claims 7 to 9.

[0013] Furthermore, a recording medium according to the invention of claim 11 is characterized in that the orientation calculation program according to claim 10 is recorded in a computer-readable manner.

Brief description of the drawing

[0014] [FIG. 1] FIG. 1 is a block diagram showing the functional configuration of a direction calculation device according to an embodiment of the present invention.

[FIG. 2] FIG. 2 is a flow chart showing the contents of processing of the direction calculation device according to the present embodiment of the invention.

[FIG. 3] FIG. 3 is a block diagram showing the hardware configuration of the navigation device in this embodiment of the invention.

[Figure 4] Figure 4 shows specifics of the direction calculation unit and correction processing unit in this embodiment of the invention. FIG. 2 is a functional block diagram showing the configuration.

[Fig. 5] Fig. 5 is a diagram illustrating the principle of azimuth calculation according to the first embodiment.

[Figure 6] Figure 6 is an explanatory diagram showing an example of an accumulation ring buffer that accumulates the amount of change at the current sampling time nT.

[Fig. 7] Fig. 7 is an explanatory diagram showing an example of an accumulation ring buffer that accumulates the amount of change at the previous sampling time nT.

[FIG. 8] FIG. 8 is an explanatory diagram showing an example of an accumulation ring buffer that accumulates the amount of change at the sampling time nT before the previous one.

[FIG. 9] FIG. 9 is a flowchart showing an overview of correction coefficient setting processing in the first embodiment.

[FIG. 10] FIG. 10 is a flowchart (part 1) showing the detailed procedure of the correction coefficient setting process in the first embodiment.

[FIG. 11] FIG. 11 is a flowchart (part 2) showing the detailed procedure of the correction coefficient setting process in the first embodiment.

[FIG. 12] FIG. 12 is a flowchart (part 3) showing the detailed procedure of the correction coefficient setting process in the first embodiment.

[FIG. 13] FIG. 13 is a flowchart (part 4) showing the detailed procedure of the correction coefficient setting process in the first embodiment.

[Fig. 14] Fig. 14 is a flowchart (part 5) showing the detailed procedure of the correction coefficient setting process in the first embodiment.

[Fig. 15] Fig. 15 is a flowchart (part 6) showing the detailed procedure of the correction coefficient setting process in the first embodiment.

[Fig. 16] Fig. 16 is a flowchart (part 7) showing the detailed procedure of the correction coefficient setting process in the first embodiment.

[Fig. 17] Fig. 17 is a flowchart (part 8) showing the detailed procedure of the correction coefficient setting process in the first embodiment.

[Fig. 18] Fig. 18 is a flowchart (part 9) showing the detailed procedure of the correction coefficient setting process in the first embodiment. [FIG. 19] FIG. 19 is a flowchart (Part 10) showing the detailed procedure of the correction coefficient setting process in the first embodiment.

[Fig. 20] Fig. 20 is a diagram illustrating the principle of azimuth calculation according to the second embodiment.

[FIG. 21] FIG. 21 is a flowchart showing an overview of correction coefficient setting processing in the second embodiment.

[Figure 22] Figure 22 is a flowchart (Part 1) showing the detailed procedure of the correction coefficient setting process in the second embodiment.

[Fig. 23] Fig. 23 is a flowchart (part 2) showing the detailed procedure of the correction coefficient setting process in the second embodiment.

[Fig. 24] Fig. 24 is a flowchart (part 3) showing the detailed procedure of the correction coefficient setting process in the second embodiment.

[Fig. 25] Fig. 25 is a flowchart (part 4) showing the detailed procedure of the correction coefficient setting process in the second embodiment.

[Figure 26] Figure 26 is a flowchart (part 5) showing the detailed procedure of the correction coefficient setting process in the second embodiment.

Explanation of symbols

[0015] 100 Direction calculation device

101 Direction calculation section

102 Recording Department

103 Detection part

104 Comparison section

105 Correction amount determination section

106 Correction direction calculation section

BEST MODE FOR CARRYING OUT THE INVENTION

[0016] Hereinafter, preferred embodiments of a direction calculation device, a direction calculation method, a direction calculation program, and a recording medium according to the present invention will be described in detail with reference to the accompanying drawings. This invention can be applied to, for example, a navigation device mounted on a vehicle. [0017] (Functional configuration of direction calculation device)

First, the functional configuration of the direction calculation device according to this embodiment of the invention will be explained. FIG. 1 is a block diagram showing the functional configuration of a direction calculation device according to this embodiment of the invention. The orientation calculation device 100 includes an orientation calculation section 101, a recording section 102, a detection section 103, a comparison section 104, a correction amount determination section 105, and a corrected orientation calculation section 106.

[0018] The azimuth calculation unit 101 calculates the relative azimuth obtained from the output value of the angular velocity sensor mounted on the vehicle based on the absolute azimuth obtained in advance, such as azimuth information included in GPS and map information. The direction (hereinafter referred to as ``sensor direction'') is calculated by cumulatively adding it to the specified reference direction. At the same time, the absolute direction (hereinafter referred to as ``GPS direction'') is calculated from the absolute position (historical information) derived from the GPS signal strength received by a GPS receiver mounted on a moving object such as a vehicle. The azimuth calculation unit 101 always calculates the azimuth when a moving object such as a vehicle on which the azimuth calculation device 100 is mounted is in a moving state. Information on the calculated orientation is output to the recording section 102, the detection section 103, the comparison section 104, and the corrected orientation calculation section 106.

[0019] The recording unit 102 records the value of the sensor orientation input from the orientation calculation unit 101 at each predetermined sampling period, with values larger than the reference value being recorded as positive changes, and values smaller than the reference value being recorded as negative changes. Record as the amount of change. The magnitude relationship of the values compared with the reference value corresponds to the right and left outputs of the angular velocity sensor. In other words, a positive amount of change represents an output to the right, and a negative amount of change represents an output to the left.

[0020] The amount of change recorded in the recording section 102 is converted into a cumulative value in the comparison section 104 for each sampling number started at a predetermined sampling time, and the cumulative value of the positive amount of change and the cumulative value of the negative amount of change are calculated. A comparison is made. Therefore, when comparing the positive and negative changes recorded in the recording section 102, the changes in the number of samplings during the designated sampling period may be added together and used as the cumulative amount. Alternatively, recording may be performed using a cumulative ring buffer in the recording unit 102.

[0021] The detection unit 103 detects a sampling time that satisfies a predetermined condition based on the sampling period at which recording is performed in the recording unit 102. In this embodiment, an example of the condition for detecting the sampling time is that the recording unit 102 has a positive or negative amount of change. When the specified number of samplings are continuously recorded, the sampling start time is the first time, and the sampling time when the cumulative values of positive and negative changes from the first time become equal is the sampling time. Examples of detection conditions include detection as the second time.

[0022] Comparison section 104 compares the azimuth values calculated by azimuth calculation section 101 at the first time detected by detection section 103 and the second time, and sends the comparison result to correction amount determination section 105. Output. More specifically, when the detection unit 103 detects two sampling times under the conditions illustrated, it compares the GPS direction values at the first time and the second time, and compares the values of the GPS direction at the first time and the second time. The value of the sensor direction at the time of is compared for each.

[0023] Correction amount determining section 105 determines the amount of correction to be performed when correcting the sensor orientation based on the comparison result input from comparison section 104. Specifically, based on the current comparison results of the sensor orientation and GPS orientation, it is determined whether the sensor orientation before correction is in an underrun state or an overrun state, and whether the sensor orientation is in an underrun state or an overrun state is determined. Processing is performed to increase or decrease the amount of correction depending on each overrun condition.

[0024]Furthermore, the correction amount determining unit 105 records the comparison results used in the past direction calculation processing, such as the previous time and the time before the previous time, and by using these values when determining the correction amount, the correction amount can be adjusted. Positive quantities can be converged. Note that it is easier to converge the past comparison results when there are more records, but they are only recorded a predetermined number of times (for example, three times), and the oldest record is updated each time a new direction calculation process is performed. Even if the direction calculation process is performed, the past comparison results are used to determine convergence each time the direction calculation process is performed, so convergence can be achieved in the same way. The correction amount determined by the correction amount determination section 105 is output to the correction direction calculation section 106.

[0025] The correction azimuth calculation unit 106 adjusts the correction coefficient using the correction amount input from the correction amount determination unit 105, and corrects the sensor azimuth input from the azimuth calculation unit 101. Calculate the corrected direction (corrected direction) after correcting the detection error. The orientation calculated by the corrected orientation calculation unit 106 is output to a navigation device or the like to which the orientation calculation device 100 is connected. [0026] Furthermore, in the case of another embodiment of the azimuth calculation device, the detection unit 103 detects the sampling time when the positive or negative amount of change is within a predetermined amount in the recording unit 102. When the number of samplings is continuously recorded, the sampling start time is detected as the first time. Thereafter, a detection condition may be such that a time when a sensor orientation equal to the sensor orientation at the first time is recorded is detected as a second time.

[0027] In another embodiment, the comparison unit 104 compares the azimuth values calculated by the azimuth calculation unit 101 at the first time and the second time, and sends the comparison result to the correction amount determination unit 105. Output to. In more detail, we will compare the GPS directions between the first time and the second time, and calculate the cumulative value of the positive change amount and the cumulative value of the negative change amount between the first time and the second time. Comparisons may be made.

[0028] (Contents of processing of direction calculation device)

Next, the contents of the processing of the direction calculation device 100 will be explained. FIG. 2 is a flowchart showing the contents of the processing of the direction calculation device according to this embodiment of the invention. Here, an example of a specific processing procedure of the direction calculation device 100 will be explained. In the flow chart of FIG. 2, first, the direction calculation unit 101 calculates the sensor direction and the GPS direction (step S201). When the process of step S201 is performed, the recording unit 102 records the positive and negative changes in the sensor orientation (step S202).

[0029] Next, it is determined whether or not a positive (negative) change amount is continuously recorded in the recording unit 102 (step S203). An example of a state in which positive (negative) changes are continuously recorded is a state in which positive (negative) changes are continuously recorded a predetermined sampling number of times. In this process, positive (negative) changes are recorded continuously; a positive change represents movement to the right, and the right output value is used as the reference, and a negative change is indicates movement to the left, and the left output value is the reference (the relationship between positive and negative and right and left may be reversed depending on the vertical installation direction of the angular velocity sensor). In addition, if the predetermined number of samplings at the moment is small because the condition is that the data be recorded continuously, for example, if the sampling period T is 100ms and the predetermined number of samplings is 10, then 1 Even if positive (negative) changes are output continuously for a second, one second is a moment of time, and it is not possible to accurately determine whether the vehicle is going to the right or left. Therefore, a stable sampling frequency is required. [0030] In step S203, wait until the positive (negative) amount of change is recorded continuously, and if the positive (negative) amount of change is recorded continuously (step S203: Yes), then , the detection unit 103 detects the time when the continuous output is started as the first time (step S204). The time when continuous output is started refers to the sampling time of the first recording at which positive (negative) changes are continuously recorded in the recording unit 102.

[0031] When the first time is detected in step S204, next, regarding the positive and negative changes recorded by the recording unit 102, the accumulated positive and negative changes from the first time are equal. (Step S 205). Here, wait until the positive and negative changes become equal, and when the accumulated positive and negative changes become equal (step S205: Yes), the detection unit 103 detects the accumulated positive and negative changes. The time that becomes equal is detected as the second time (step S 206).

[0032]Next, the comparison unit 104 compares the GPS direction and the sensor direction at the first time and the second time (step S207). Next, the correction amount determination unit 105 determines the correction amount according to the comparison result in step S207 (step S208). Finally, the correction azimuth calculation unit 106 calculates a correction azimuth in which the sensor azimuth is corrected using the correction amount determined in step S208 (step S209), and the series of processes ends.

[0033] As explained above, according to the azimuth calculation device 100 of the present embodiment, the sensor azimuth in which the angular velocity sensor force was also calculated, the GPS azimuth in which the GPS signal force was also calculated, and the cumulative amount of change in the sensor azimuth are used. It is possible to determine the amount of correction suitable for correcting the detection error (hereinafter referred to as "detection error") due to the sensitivity difference (gain difference) of the angular velocity sensor depending on the turning direction of the vehicle in the sensor orientation calculated by the angular velocity sensor. . By adjusting the correction coefficient using the correction amount determined in this way, highly accurate error correction can be performed automatically.

[0034] In the case of another embodiment, the detection unit 103 detects the two times when the sensor orientations become equal as the first time and the second time, and the comparison unit 104 detects the two times when the sensor orientations become equal as the first time and the second time. A comparison of the GPS direction between the first time and the second time, and a comparison of the positive and negative change amounts between the first time and the second time may be performed and output to the correction amount determination unit 105. Embodiment described above Similarly, highly accurate error correction can be performed automatically.

[0035] Furthermore, the two embodiments described above use the parameters detected by the same detection means (cumulative values of positive and negative changes, sensor orientation, and GPS orientation) to determine the GPS orientation. Comparison and comparison of sensor orientation, comparison of GPS orientation, and comparison of cumulative values of positive and negative changes are performed, so by providing two comparison function units in the comparison unit 104, orientation calculation is possible. They can also be executed simultaneously without changing the configuration of the device 100. By executing the two embodiments simultaneously, the number of error corrections can be increased, and more accurate navigation can be performed.

Example 1

[0036] Example 1 of the present invention will be described below. In Embodiment 1, an example in which the orientation calculation device of the present invention is implemented by a navigation device mounted on a moving object such as a vehicle (including four-wheeled vehicles and two-wheeled vehicles) will be described.

[0037] (Hardware configuration of navigation device)

First, the hardware configuration of the navigation device in this embodiment of the invention will be explained. FIG. 3 is a block diagram showing the hardware configuration of the navigation device in this embodiment of the invention. The navigation device 300 in this embodiment of the invention includes a navigation control section 301, a user operation section 302, a display section 303, a recording medium 304, a recording medium decoding section 305, and a guide sound output section 306. , a communication section 307, a route search section 308, a route guidance section 309, a guide sound generation section 310, a speaker 311, a position acquisition section 312, a direction calculation section 313, and a correction processing section 314. Ru.

[0038] First, the navigation control unit 301 controls the entire navigation device 300.

The navigation control unit 301 includes, for example, a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a ROM (Read Only Memory) that stores various control programs, and a RAM (Random Processing Unit) that functions as a work area for the CPU. This can be realized by a microcomputer configured with an access memory (Access Memory), etc. For example, the RAM stores correction coefficients used when calculating angular velocity. In the force RAM, which will be described in detail later, one correction coefficient is stored for each turning direction of the vehicle. In this embodiment, the correction coefficient for the left gain difference is The number Gl and the correction coefficient Gr for the right gain difference are memorized (see Figure 4). Each correction coefficient G1 and Gr is stored in a freely updatable manner.

[0039] During route guidance, the navigation control unit 301 inputs and outputs information regarding route guidance to and from the route search unit 308, route guidance unit 309, and guide sound generation unit 310, and uses the information obtained as a result. It is output to the display section 303 and the guide sound output section 306.

[0040] Furthermore, the user operation unit 302 outputs information input and operated by the user, such as characters, numbers, and various instructions, to the navigation control unit 301. As the configuration of the user operation unit 302, it is possible to adopt various known forms such as a pushbutton switch that detects physical pressing and non-pressing of Z, a touch panel, a keyboard, a joystick, etc. The user operation unit 302 may be configured to perform input operations by voice using a microphone that inputs voice from the outside.

[0041] The user operation unit 302 may be provided integrally with the navigation device 300, or may be operated separately from the navigation device 300, such as a remote control. The user operation unit 302 may be configured in any one of the various configurations described above, or may be configured in a plurality of configurations. The user inputs information by performing an appropriate input operation depending on the form of the user operation unit 302. Examples of information input by operating the user operation unit 302 include the destination (destination point information) or the departure point (departure point information) of the route to be searched.

[0042] In addition to inputting the latitude and longitude and address of each point, the destination or departure point can also be entered by specifying the telephone number, genre, keyword, etc. of the facility serving as the destination or departure point. good. By inputting the destination or departure point by specifying the phone number, genre, keyword, etc. of the facility that is the destination or departure point, the corresponding facility is searched and the location is identified as the destination or departure point. can do. More specifically, this information is identified as a point on the map based on background type data included in map information recorded on a recording medium 304, which will be described later. Alternatively, map information may be displayed on the display section 303, the details of which will be described later, and one point on the displayed map may be specified.

[0043] The display section 303 may be, for example, a CRT (Cathode Ray Tube) or a TFT liquid crystal display. This includes LED displays, organic EL (Electroluminescence) displays, plasma displays, etc. Specifically, the display unit 303 can be configured by, for example, a video IZF or a display device for displaying video connected to the video IZF.

[0044] Specifically, the video IZF includes, for example, a graphics controller that controls the entire display device, a buffer memory such as VRAM (Video RAM) that temporarily stores image information that can be displayed immediately, It consists of a control IC that controls the display device based on the image information output from the graphics controller. The display section 303 displays icons, cursors, menus, windows, and various information such as text and images. Furthermore, the display section 303 displays map information and route guidance information stored in an HD (Hard Disk).

[0045] Furthermore, the recording medium 304 records map information, various control programs, various information, etc. in a state readable by a computer. The recording medium 304 receives information written by the recording medium decoding unit 305 and records the written information in a non-volatile manner. The recording medium 304 can be realized by, for example, HD. In the present embodiment, the recording medium 304 records an orientation calculation program. Note that the direction calculation program is not limited to that recorded on the recording medium 304.

[0046] The recording medium 304 is not limited to HD, but instead of or in addition to HD, DVD (Digital Versatile Disk), CD (Compact Disk), etc. can be attached to and detached from the recording medium decoding unit 305. A portable medium may be used as the recording medium 304. The recording medium 304 is not limited to DVDs and CDs, but also includes CD-ROMs (CD-Rs, CD-RWs), MOs (Magneto-Optical disks), memory cards, etc., which can be attached to and removed from the recording medium decoding section 305. It is also possible to use portable media.

[0047] The map information recorded in the recording medium 304 includes background data representing features such as buildings, rivers, and the ground surface, and road shape data representing the shape and direction of the road. The image is drawn in two or three dimensions on the display screen of the display unit 303. Road shape data is also used, for example, in map matching. The map information recorded on the recording medium 304 is displayed overlappingly with the own vehicle position acquired by the position acquisition unit 312, for example, when the navigation device 300 is guiding a route. [0048] In this embodiment, the map information is recorded on the recording medium 304, but the present invention is not limited to this. The map information is not limited to being recorded integrally with the hardware of the navigation device 300, but may be provided outside the navigation device 300. In that case, the navigation device 300 acquires map information via the network, for example through the communication unit 307. The acquired map information is stored in RAM, etc.

[0049] Furthermore, the recording medium decoding unit 305 controls reading and writing of information on the recording medium 304. For example, when an HD is used as the recording medium 304, the recording medium decoding section 305 becomes an HDD (Hard Disk Drive). Similarly, when a DVD or a CD (including CD-R and CD-RW) is used as the recording medium 304, the recording medium decoding section 305 becomes a DVD drive or a CD drive. When using a CD-ROM (CD-R, CD-RW), MO, memory card, etc. as a writable and removable recording medium 304, it is possible to write information to and write information to various recording media. A dedicated drive device capable of reading stored information is appropriately used as the recording medium decoding section 305.

[0050] Further, the guide sound output section 306 reproduces the guide sound by controlling output to the connected speaker 311. The number of speakers 311 may be one or multiple. Specifically, the guide sound output unit 306 can be realized by an audio IZF connected to a speaker 311 for audio output. More specifically, the audio IZF includes, for example, a DZA conversion circuit that performs DZA conversion of audio digital information, an amplifier that amplifies the audio analog signal output from the DZA conversion circuit, and an AZD conversion of audio analog information. The AZD conversion circuit and the AZD conversion circuit can be configured separately.

[0051] The communication unit 307 receives traffic information such as traffic jams and traffic regulations regularly (or irregularly). The communication department 307 may receive traffic information at the timing when traffic information is distributed from the VICS (Vehicle Information and Communication System) center, or it may receive traffic information by periodically requesting traffic information from the VICS center. Let's go.

[0052] The communication unit 307 can be realized as, for example, an FM tuner, a VICSZ beacon receiver, and other communication equipment. The received traffic information is used for route searching ( (including re-search), and is used, for example, to search for routes that avoid traffic jams or time-limited locations.

[0053] Since it is a well-known technology, detailed explanation will be omitted. ``VICS'' is a technology that transmits traffic information such as congestion and traffic regulations edited and processed at the VICS center in real time to navigation devices such as the 300. It is an information communication system that displays characters and figures. One way to transmit traffic information (VICS information) edited and processed at the VICS center to the navigation device 300 is to use ``beacons'' installed on each road and ``FM multiplex broadcast.''

[0054] "Beacons" include "radio wave beacons", which are mainly used on expressways, and "optical beacons", which are used on major general roads. When using FM multiplex broadcasting, it is possible to receive traffic information for a wide area. When using a beacon, it is possible to receive necessary traffic information based on the location of the vehicle, such as detailed information on the nearest roads based on the location of the vehicle.

[0055] Furthermore, the route search unit 308 uses map information recorded in the recording medium 304, VICS information acquired via the communication unit 307, etc. to Search for the optimal route to the destination (destination point information). Here, the optimal route is the route that best matches the conditions specified by the user. Generally, there are an infinite number of routes from a departure point to a destination. For this reason, we set the items to be considered when searching for a route, and search for a route that meets the conditions.1.

[0056] The route guidance unit 309 also receives the guidance route information searched by the route search unit 308, the own vehicle position information acquired by the position acquisition unit 312, and the information from the recording medium 304 via the recording medium decoding unit 305. Real-time route guidance information is generated based on the map information obtained. The route guidance information generated at this time may take into consideration the traffic information received by the communication unit 307. The route guidance information generated by the route guidance section 309 is output to the display section 303 via the navigation control section 301.

[0057] Further, the guide sound generation unit 310 generates tone and voice information corresponding to the pattern.

That is, based on the route guidance information generated by the route guidance unit 309, a virtual sound source corresponding to the guidance point is set and voice guidance information is generated. It is output to the guide sound output section 306 via the section 301.

[0058] The position acquisition unit 312 is also configured with a GPS receiver and various sensors, and acquires information on the current position of the vehicle and orientation information indicating the orientation of the vehicle. This direction information is referred to as GPS direction. The GPS receiver receives radio waves from GPS satellites and determines the geometric position relative to the GPS satellites. Note that GPS is a system that accurately determines the position on the ground by receiving radio waves from four or more satellites.

[0059] The GPS receiver specifically includes, for example, an antenna for receiving radio waves from GPS satellites, a tuner for demodulating the received radio waves, and an arithmetic circuit for calculating the current position based on the demodulated information. (or program) etc.

[0060] In addition, the various sensors include various sensors mounted on the vehicle, such as a vehicle speed sensor, a mileage sensor, an inclination sensor, and an angular velocity sensor. When calculating vehicle position and direction information, the vehicle position can be obtained with higher accuracy by using information output from various sensors installed in the vehicle, along with information obtained from external forces by the GPS receiver. can do.

[0061] The vehicle speed sensor detects the number of vehicle speed pulses per rotation from the output side drive shaft of the transmission of the vehicle in which the navigation device 300 is installed. The mileage sensor calculates the number of pulses per rotation of the wheel by counting the number of pulses of a pulse signal of a predetermined period that is output as the wheel rotates, and calculates the number of pulses per rotation of the wheel based on the number of pulses per rotation. Output mileage information. The inclination sensor detects the inclination angle of the road surface. The angular velocity sensor detects the angular velocity of the vehicle when turning.

[0062] Specifically, the angular velocity sensor can be realized by, for example, a vibration gyro sensor using a piezoelectric element or the like as a detection element. In this case, the angular velocity sensor outputs a voltage value corresponding to the angular velocity of the vehicle when turning. Here, for example, if the output value of the angular velocity sensor is 2.5V (specified zero point voltage), it indicates that the angular velocity is zero (0[deg/s]).

[0063] Incidentally, the angular velocity becomes zero when the vehicle is stationary or when the vehicle is traveling straight. In many cases, the value is drifting due to the Therefore, in this example, the car The output value from the angular velocity sensor when both vehicles are stationary, or the output value from the angular velocity sensor force when the vehicle is moving straight, is corrected for the influence of temperature drift, and is used as the zero point (offset) voltage value.

[0064] The angular velocity sensor outputs the detected angular velocity as an analog signal of OV to 5V. The sensitivity of an angular velocity sensor is expressed as the degree of deviation of the angular velocity from the zero point (offset) voltage (specified zero point voltage of 2.5V), and its unit is [mVZdegZsec]. It is assumed that the sensitivity of the angular velocity sensor complies with the standards specified in the horizontal state and is adjusted to fall within the specified error. Hereinafter, in this embodiment, the value obtained by subtracting the zero point (offset) voltage value from the voltage value output from the angular velocity sensor is referred to as the "output value from the angular velocity sensor." The output value of the angular velocity sensor force is obtained, for example, at every sampling period T. This sampling period T can be set to any value, and is specifically set to, for example, 10 Omsec.

[0065] The angular velocity sensor outputs a positive angular velocity corresponding to a clockwise azimuth change, that is, a right turn, as a deviation voltage from 2.5V to the 5V side. On the other hand, this angular velocity sensor outputs a negative angular velocity corresponding to a counterclockwise direction change, that is, a left turn, as a deviation voltage from 2.5V to the OV side. Note that when a vibrating gyroscope is used as the angular velocity sensor, an AZD conversion circuit 420 (see FIG. 4) is provided to convert the analog voltage value detected by the vibrating gyroscope into AZD.

[0066] The azimuth calculation unit 313 integrates the value obtained by multiplying the output value of the angular velocity sensor force by the gain value and either the right gain difference correction coefficient Gr or the left gain difference correction coefficient G1 over a sampling period T. Then, the absolute direction (hereinafter referred to as "sensor direction") is calculated by accumulating the previously calculated direction. In this way, the detection error of the angular velocity sensor is detected using the sensor orientation calculated from the output from the angular velocity sensor and the GPS orientation calculated from the GPS signal strength received by the GPS receiver, and the detection result is corrected by the correction processing unit 314 By linking it with the above, it is possible to determine the amount of correction and calculate the corrected direction that corrects the detection error.

[0067] The direction calculation unit 313 can be realized by, for example, a dedicated arithmetic circuit or a program. Further, the direction calculation section 313 calculates the sensor direction at every sampling period T, and at this time, the direction calculation section 313 calculates the sensor direction and calculates the GPS direction in the position acquisition section 312. Synchronize the output.

[0068] The correction processing unit 314 performs a process of updating a correction coefficient for correcting the sensor orientation based on the detection error of the sensor orientation calculated by the orientation calculation unit 313. After comparing the GPS orientation at the first time and the GPS orientation at the second time recorded on the recording medium 304, the result of comparing the sensor orientation at the first time and the sensor orientation at the second time ( Using either Example 1) or the results of comparing the cumulative values of positive and negative changes accumulated from the first time force to the second time (Example 2 described later), Determine whether the value is underrun or overrun at the second time. Also, if either the negative change amount (leftward output value) criterion or the positive change amount (rightward output value) criterion determined at the first time is used as a reference, the Update either the left or right gain difference correction coefficient G1 or Gr. Note that the left and right gain difference correction coefficients G1 and Gr will be explained with reference to FIG.

[0069] Next, the specific configurations of the orientation calculation section 313 and the correction processing section 314 in this embodiment of the invention will be described. FIG. 4 is a functional block diagram showing a specific configuration of the orientation calculation section 313 and the correction processing section 314 in this embodiment of the invention. Specifically, the various functions described above in the direction calculation section 313 and the correction processing section 314 are realized, for example, by the respective sections shown in FIG. 4. The azimuth calculation unit 313 and the correction processing unit 314 in this embodiment of the invention include a subtraction processing unit 401, a multiplication processing unit 402, a sum of products processing unit 403, a straight-ahead determination processing unit 404, and a zero point adjustment processing unit 405 , azimuth calibration processing section 406 , comparison processing section 407 , negative change amount reference determination processing section 408 , positive change amount reference determination processing section 409 , left gain difference correction coefficient adjustment processing section 410 , right gain It includes a difference correction coefficient adjustment processing section 411 and a correction coefficient selection and acquisition processing section 412. Note that the reference numeral 420 in FIG. 4 is an AZD conversion circuit that converts the output value of the analog output value of the angular velocity sensor into AZD.

[0070] First, the subtraction processing unit 401 subtracts the zero point (offset) voltage value output from the angular velocity sensor. A digital value that has been AZD converted by the AZD conversion circuit 420 is input to the subtraction processing unit 401. The multiplication processing unit 402 multiplies the output value from the angular velocity sensor by a gain value, and multiplies this multiplication value by a correction coefficient Gr for the right gain difference if the multiplication value is positive, and by a correction coefficient G1 for the left gain difference if it is negative. and calculate the angular velocity. In addition, the gain value is a value set based on the correspondence between the output value from the angular velocity sensor and the angular velocity.

[0071] Furthermore, the product-sum processing unit 403 accumulates the relative azimuth displacement amount calculated by integrating the angular velocity currently calculated by the multiplication processing unit 402 over the sampling period T, to the previous sensor azimuth. Then, the calculated sensor orientation of the vehicle is calculated. The straight-ahead determination processing unit 404 determines whether the vehicle is in a straight-ahead state based on the angular velocity calculated by the multiplication processor 402. Specifically, the straight-ahead determination processing unit 404 determines whether the displacement amount of the angular velocity calculated by the multiplication processing unit 402 is within a predetermined period (for example, 10 km/h) or higher when traveling at a certain speed (for example, 30 km/h) or higher. If the value is less than a predetermined threshold for a period of 2 seconds, it is determined that the vehicle is traveling straight.

[0072] Furthermore, when the straight-ahead determination processing unit 404 determines that the vehicle is in a straight-ahead state, the zero-point adjustment processing unit 405 adjusts the output value so that the average value of the output values from the angular velocity sensor during the predetermined period approaches the average value. Adjust the zero point (offset) voltage value. The azimuth calibration processing unit 406 performs azimuth calibration using another absolute azimuth obtained from the position acquisition unit 312 and the storage medium 304 in order to eliminate the influence of the dynamic zero point drift of the angular velocity sensor. If the current calculated relative azimuth displacement continues to be accumulated on the previous sensor azimuth, the cumulative error will increase, so the sensor azimuth is calibrated using the GPS azimuth or road shape azimuth data from map information.

[0073] Specifically, for example, when the vehicle is traveling straight at a vehicle speed V equal to or higher than a predetermined value, the calculated sensor orientation is calibrated with the GPS orientation acquired by the position acquisition unit 312. Further, specifically, for example, during intersection pull-in processing, the sensor orientation is calibrated using map orientation data in map data. In the case of this embodiment, the comparison processing unit 407 divides the cases based on the result of comparing the detected GPS azimuth at the first time and the detected GPS azimuth at the second time. Then, among those cases, the sensor orientation at the first time and the sensor orientation at the second time are compared.

[0074] Negative change amount reference determination processing section 408 determines whether or not a negative change amount is continuously output for a predetermined sampling number of times. Similarly, the positive change amount reference determination processing unit 409 determines whether or not a positive change amount has been continuously output a predetermined sampling number of times.

[0075] The left gain difference correction coefficient adjustment processing section 410 uses the positive change amount standard judgment processing section 409. When it is determined that the right output value is stable and has been output continuously for a predetermined sampling number of times, the left output value is corrected based on the right turn direction output value, that is, the left gain difference correction is performed to correct the left gain difference. Correct (update) coefficient G1.

[0076] The right gain difference correction coefficient adjustment processing unit 411 performs a left turn when the negative change amount standard judgment processing unit 408 determines that the left output value has been output continuously for a stable predetermined number of sampling times. Based on the direction output value, the right output value is corrected, that is, the right gain difference correction coefficient Gr for correcting the right gain difference is corrected (updated).

[0077] The left gain difference correction coefficient adjustment processing section 410 and the right gain difference correction coefficient adjustment processing section 411 adjust (update) the correction coefficient by determining and updating the correction amount for the currently set correction coefficient. For example, six types of correction amounts are used, such as ±0. 4%, ±0. 2%, ±0. 1%, etc., and the cumulative value of the positive change from the first time to the second time is calculated. When the cumulative values of negative changes match, case classification is performed based on the comparison result between the acquired GPS bearing Gam at the first time and the GPS bearing Gbn at the second time and the sensor bearing at the first time. It is changed at any time based on the comparison result between Sam and the sensor orientation Sbn at the second time (the specific changing method will be explained in detail using flowcharts in FIGS. 10 to 19). This correction amount is changed by observing changes in the sensor orientation of the vehicle at the first time and the sensor orientation at the second time so that the gain value converges to the correct value.

[0078] When the output value of the angular velocity sensor force is negative, the correction coefficient selection acquisition processing unit 412 selects the correction coefficient G1 for the left gain difference adjusted by the left gain difference correction coefficient adjustment processing unit 410. do. Furthermore, when the output value from the angular velocity sensor is positive, the correction coefficient selection and acquisition processing unit 412 selects the correction coefficient Gr for the right gain difference adjusted by the right gain difference correction coefficient adjustment processing unit 411. The correction coefficients selected by the correction coefficient selection and acquisition processing section 412 are used in the calculation of the angular velocity in the multiplication processing section 402.

[0079] (Principle of direction calculation in Example 1)

FIG. 5 is a diagram illustrating the principle of azimuth calculation according to the first embodiment. In chart 500 shown in FIG. 5, the horizontal axis represents time t, and the sampling period T is shown by a vertical line (dashed line). In addition, the upper row at the bottom of the chart 500 for the sampling period T interval shows the number of samples (l to n), and the lower row at the bottom of the chart 500 shows the sampling time (0T to nT) with 0T as the start time. Show each. The vertical axis represents the output range of the acceleration sensor, OV~5V, in the digital value unit [LSB]. For example, in the case of a 12-bit AZD converter, OV~5V is divided by 4096, resulting in 1.22mV/LSB.

[0080] Curve 501 is, for example, the output when the sampling period T is 100 [ms] and AZD conversion is performed 20 times (5 ms intervals) in 100 [ms] using an external 12-bit AZD converter. It represents a value. Then, using the formula (1) below, perform averaging processing for 100 [ms], and every 100 [ms], the average value of the AZD conversion data of the output value of the angular velocity sensor for 100 [ms] gyn represents.

[0081] [Number 1] gyn-- / 20 … ke)

[0082] If the average value gyn of the angular velocity sensor output after AZD conversion is larger than the offset (zero point) voltage value gyO, the angular displacement amount (relative azimuth displacement amount) of the sensor orientation Θ gn toward the right of the vehicle is detected. represents something. In addition, the average value gyn force after AZD conversion of the angular velocity sensor output shown by curve 501 is also the offset (zero point) voltage value gyO subtracted (gyn-gyO), which is V, the so-called "output value from the angular velocity sensor". be. This value is multiplied by the gain value G, and then either the right gain difference correction coefficient Gr or the left gain difference correction coefficient G1 is set depending on the positive or negative value of the "output value from the angular velocity sensor" (gyn-gyO). By multiplying by the left and right gain difference correction coefficient Gkn-1, the angular velocity ω η can be calculated using the following equation (2).

[0083] o n=Gkn— Ι -G· (gyn-gyO) [deg/100ms] - -- (2)

[0084] This angular velocity ω η is expressed by one sampling of each of the ranges 502a, 502b, and 502c shown by the rectangular lines in FIG. 5, and the ranges 503a and 503b shown by the rectangular lines. For example, range 502a represented by square lines represents 2 samples, range 502b represents 3 samples, range 502c represents 2 samples, range 503a represents 4 samples, and range 503b represents 4 samples. Represents 2 samplings.

[0085] The sampling times of the entire range indicated by these rectangular lines from 1T hour to nT hour are successively integrated over the sampling period T for each sampling, and the result is calculated at each sampling time. The angular displacement amount Δ Θ ₈ 1 to Δ 0 gn is accumulated to the previous sensor orientation Θ gO to Θ gn− 1 at each sampling time. By repeating this process for the number of sampling times for the entire range, the sensor orientation Θ gn can also be obtained for the entire range force shown by the rectangular line. Note that the range 502a to 502c shown by the square line represents the positive (right) angular displacement amount, and the range 503a to 503b represents the negative (left) angular displacement amount.

[0086] As shown in FIG. 5, when the vehicle is moved, the output value of the angular velocity sensor force (gyn-gyO) constantly changes while showing positive and negative values. Therefore, in this embodiment, for example, when a negative change amount is recorded in the curve 501 shown in Figure 500 continuously for k sampling times, the sampling time mT at which the recording of the negative change amount started is detected. . In addition, the sensor orientation Sam (θ 1) and the GPS orientation Gam (Θ 2) calculated at the sampling time mT are shown in the orientation unit circle 504 expressed in the GPS orientation system. In the case of chart 500, the negative change amount is recorded k times in a row, so the right gain difference is corrected based on the cumulative value of the leftward angular displacement amount.

[0087] As in the example shown in Chart 500, a sampling time nT is detected at which the cumulative values of the positive and negative changes starting from the sampling time mT are equal. In other words, the sampling time nT is such that (range 502b + 502c representing the amount of positive change) = I (range 503a + 503b representing the amount of negative change) | Also, what is shown on the vertical axis representing the sampling time nT is the azimuth unit circle 505 in which the GPS azimuth Gbn ( Θ 4) and the sensor azimuth Sbn ( Θ 3) calculated at the sampling time nT are expressed in the GPS azimuth system. show. In Example 1, first, the GPS directions Gam (Θ 2) and Gbn (Θ 4) at the sampling time mT and the sampling time nT are compared, and the magnitude of the comparison results Gam and Gbn is determined. Next, among these cases, we compare the sensor orientations Sam ( θ 1) and Sbn ( Θ 3) at sampling time mT and sampling time nT, and from the comparison results, we can distinguish between the large and small values of Sam and Sbn. be exposed. Then, based on the results of the double case classification of the GPS direction and the sensor direction, it is determined whether the sensor direction Sbn is in an overrun state or an underrun state from Sam, and the left and right gain difference correction coefficient G1 or Gr is adjusted. Determine the correction amount for either one.

[0088] Here, in the following explanation, the cumulative amount of change of either the previous positive (right) or negative (left) (output value ≠ 0) and the other (output value = 0) will be used. Ring buffer accumulation Add "'" to the value related to the process, and accumulate the amount of change of either positive (right) or negative (left) (output value ≠ 0) and the amount of change of the other (output value = 0) two times before. Values related to accumulation processing of the accumulation ring buffer are indicated with ``''. First, at sampling time nT, when comparing the cumulative value of positive changes (right output value) from sampling time mT with the cumulative value of negative changes (left output value), the sampling period T For each case, either the positive (right) or negative (left) amount of change (output value ≠ 0) corresponds to the cumulative value accumulated in the cumulative buffer (n—m) in the cumulative ring buffer, and the amount of change ( The other one whose output value (output value) is “0” uses the cumulative value accumulated in the cumulative buffer (n—m) in the corresponding cumulative ring buffer (see Figure 6). In Example 1 and Example 2, the three cumulative ring buffers have negative (left) changes: this time (sampling time nT), the previous time (sampling time n'T), and the time before the previous time (sampling time n''T). There are six in total, two for quantity and two for positive (right) change.

[0089] Next, we will explain how the accumulation occurs in the accumulation ring buffer that accumulates the amount of change in either the positive (right) or negative (left) (output value ≠ 0) and the amount of change in the other (output value = 0). This will be explained using Figures 6 to 8. FIG. 6 is an explanatory diagram showing an example of an accumulation ring buffer that accumulates the amount of change at the current sampling time nT. Further, FIG. 7 is an explanatory diagram showing an example of an accumulation ring buffer that accumulates the amount of change at the previous sampling time nT. Further, FIG. 8 is an explanatory diagram showing an example of an accumulation ring buffer that accumulates the amount of change at the sampling time nT before the previous one.

[0090] First, a description will be given of the accumulation process in the accumulation ring buffer that accumulates the amount of change at the current sampling time nT. For example, table 610 shown in Figure 6 has a ring buffer 611 indicating the current negative change amount (left output value) cumulative buffer, and a ring buffer 612 showing the current gender change amount (right output value) cumulative buffer. It consists of When a change amount 613 indicating either the positive (right) or negative (left) change amount (output value ≠ 0) and the other change amount (output value = 0) at the current sampling time nT is detected, the change amount 613 is accumulated in ring buffer 611 or ring buffer 612 depending on whether it is a positive or negative value.

[0091] First, if the amount of change (output value ≠ 0) in the sensor orientation for the past one sampling period (1T) from the current sampling time nT is a negative amount of change (left output value), the change is shown in the ring buffer 611. The lowest “Negative change amount (left output value) cumulative buffer 1” to the highest “Negative change amount (left output value) After accumulating the negative change amount (left output value) in all of the cumulative buffer n (output value), shift one buffer in the upper direction. Therefore, the highest level "negative change amount (left output value) accumulation buffer n" becomes negative change amount (left output value) accumulation buffer n+ 1 and is removed from ring buffer 61 1 (data string 614). . Then, the negative change amount (left output value) is stored in the vacant lowest ``negative change amount (left output value) cumulative noffer 1''. In addition, the number of samples for each of the ``negative change amount (left output value) cumulative buffer 1, 2, 3, ~, (n- 2), (n- 1), n'' shown in ring buffer 611 is `` 1, 2, 3, ~, (n- 2), (n- 1), n, and so on, increasing by 1 from the lowest to the highest buffer!/ ,ru.

[0092] Similarly to the above explanation, the ring buffer 621 indicating the previous negative change amount (left output value) cumulative buffer in the table 620 shown in Figure 7 is the positive (right) value at the previous sampling time nT. When a negative (left) change amount of 623 is detected, which indicates the amount of change on one side (output value ≠ 0) and the amount of change on the other side (output value = 0), one sampling cycle (1 T) from the previous sampling time nT is detected. ) in the sensor orientation (output value≠0) is a negative change (left output value), the topmost “negative change (left output value) cumulative buffer η” is a negative change (output value≠0) The amount of change (left output value) becomes cumulative buffer n+ 1 and is removed from ring buffer 621 (data string 624).

[0093] Table 630 shown in Figure 8 shows the cumulative buffer of the negative change amount (left output value) two times before the previous time. When detecting the amount of change 63 3 indicating the amount of change on one side (output value ≠ 0) and the amount of change on the other side (output value = 0), the sensor direction for the past one sampling period (1T) from the sampling time nT before the previous one is detected. When the amount of change (output value ≠ 0) is a negative amount of change (left output value), the topmost “negative amount of change (left output value) cumulative buffer η” is the amount of negative change (left output value). value) Cumulative buffer becomes η+ 1 and is removed from ring buffer 631 (data string 634).

[0094] Next, if the current sampling time nT force is also a positive change (output value ≠ 0) in the sensor orientation over the past one sampling period (1T), it is shown in the ring buffer 612. from the lowest “positive change amount (right output value) cumulative buffer 1” to the highest “positive change amount (right output value) cumulative buffer η” from the current sampling time nT to the past one sampling period. After apparently accumulating the positive amount of change (right output value) in which the amount of change (output value) in the sensor orientation for (1T) minutes is "0", shift one buffer in the upper direction. Therefore, the top The “positive change amount (right output value) cumulative buffer n” becomes the positive change amount (left output value) cumulative buffer n+ 1 and is removed from the ring buffer 612 (data string 615). Then, the positive change amount (right output value) is stored in the vacant lowest “positive change amount (right output value) accumulation buffer 1”. In addition, the number of samples for each of the "positive change amount (right output value) cumulative buffer 1, 2, 3, ~, (n- 2), (n- 1), n" shown in the ring buffer 612 is "1". The numbers are increased one by one from the lowest to the highest buffers, such as ``2, 3, ~, (n-2), (n-l), n''.

[0095] Similar to the above explanation, the ring buffer 621 indicating the previous positive change amount (right output value) cumulative buffer in the table 620 shown in Figure 7 is the positive (right) value at the previous sampling time nT. When a negative (left) change amount of 623 is detected, which indicates the amount of change on one side (output value ≠ 0) and the amount of change on the other side (output value = 0), one sampling cycle (1 T) from the previous sampling time nT is detected. ) in the sensor orientation (output value≠0) is a positive change (right output value), the topmost “positive change (right output value) cumulative buffer η” is a positive change (output value≠0). The amount of change (right output value) becomes cumulative buffer n+ 1 and is removed from ring buffer 622 (data string 625).

[0096] Table 630 shown in Figure 8 shows the cumulative buffer of positive change amount (right output value) two times before the previous time. When detecting the amount of change 63 3 indicating the amount of change on one side (output value ≠ 0) and the amount of change on the other side (output value = 0), the sensor direction for the past one sampling period (1T) from the sampling time nT before the previous time is detected. When the amount of change (output value ≠ 0) is a positive amount of change (right output value), the topmost “positive amount of change (right output value) cumulative buffer η” is the amount of positive change (right output value). value) Cumulative buffer becomes η+ 1 and is removed from ring buffer 632 (data string 635).

[0097] (Processing procedure for calculating direction in Example 1)

FIG. 9 is a flowchart showing an overview of the correction coefficient setting process in the first embodiment. What will now be described is the processing procedure involved in updating the correction coefficient for the left and right gain difference, which is a feature of the present invention. This is the processing in the correction coefficient adjustment processing section 411 and the correction coefficient selection acquisition processing section 412. The orientation calculation unit 313 (see FIG. 3) calculates the orientation using the correction coefficient set by the procedure described below. In the flowchart shown in Figure 9, first The sensor direction and GPS direction are recorded every pulling cycle T (step S901).

[0098] Next, at every sampling period T, the amount of change in either the positive (right) or negative (left) sensor orientation (output value ≠ 0) and the amount of change in the other (output value = 0) are cumulatively recorded. (Step S9 02). Here, the positive amount of change represents the right output value of the sensor orientation, and the negative amount of change represents the left output value of the sensor orientation.

[0099]Next, in the process in step S902, it is determined whether or not the amount of change, either positive (right) or negative (left), has been continuously recorded k sampling times (step S903). Here, wait for either the positive (right) or negative (left) change amount to be recorded ¾ times in a row, and if it is recorded (Step S903: Yes), the positive (right) change If the amount of change is recorded continuously, perform left gain difference correction!, and if negative (left) change amount is continuously recorded, perform right gain difference correction (step S904). At the same time, the sampling time mT at which continuous changes in the same bending direction have started is detected (step S905).

[0100] Next, from the sampling time mT, for each sampling period T, calculate the amount of change in either the positive (right) or negative (left) (output value ≠ 0) and the amount of change in the other (output value = 0). Accumulate (step S906). Next, it is determined whether or not the cumulative value of the positive (right) amount of change that started to be accumulated in step S906 is equal to the cumulative value of the negative (left) amount of change (step S907). Here, wait until the cumulative value of the positive (right) amount of change and the cumulative value of the negative (left) amount of change are equal, and if they become equal (Step S907: Yes), the cumulative value is The sampling time nT that has become equal is detected (step S908).

[0101] Note that the sensor orientation at sampling time mT is Sam ( θ 1), and the GPS orientation is Gam (

Θ 2), the sensor orientation at sampling time nT is represented by Sbn ( Θ 3), and the GPS orientation is represented by Gb η ( θ 4). Also, the cumulative value of positive changes at sampling time nT is expressed as Θ rn, and the cumulative value of negative changes is expressed as I 0 In I.

[0102] Next, the GPS azimuth Gam (Θ 2) at the sampling time m T detected in step S905 and step S908 is compared with the GPS azimuth Gbn (Θ 4) at the sampling time nT (step S909), Next, the sensor orientation Sam (θ 1) at the sampling time mT is compared with the sensor orientation Sbn (Θ 3) at the sampling time nT (step S910). Therefore, when the GPS direction is compared with the sensor direction, the correction is made based on this comparison result. Determine the amount (step S911).

[0103]Finally, one of the correction coefficients G1 and Gr is adjusted using the correction amount determined in step S911 (step S912), and the series of processes ends. As explained above, by repeating the process of updating the correction coefficient, the correction coefficient approaches the converged value.

[0104] FIGS. 10 to 19 are flowcharts showing detailed procedures of the correction coefficient setting process in the first embodiment. In the flowchart shown in Figure 10, first, at the current sampling time nT, it is determined whether the GPS positioning state is a three-dimensional positioning state (step S1001), and then, the GPS speed data is determined to be 30 [kmZh]. or more (step S10)

02) and determines whether the vehicle speed pulse speed is 30 [kmZh] or more (step S1).

003).

[0105] At the current sampling time nT, if all the conditions in step S1001 to step S1003 are satisfied (step S1001 to step S1003: Yes), then the amount of change in the average angle of the GP S direction is 0. It is determined whether the force is less than 3 [deg] (step S 1004), and then the angular acceleration, which is the displacement amount of the angular velocity [degZs] calculated from the output of the angular velocity sensor, is 0.3 [deg/s · s] or less (step S 1005).

[0106] At the current sampling time nT, if the condition does not apply in each step from step S1001 to step S1003 (step S1001 to step S1003: No), or if the condition does not apply at each step from step S1001 to step S1003, or if the condition does not apply at each step from step S1001 to step S1003 If the conditions are met in each step (steps S1004, S1005: Yes), the process moves to step S1006, and the positive and negative changes (right and left output values) cumulative ring buffers are all cleared to zero (step S1006). , completes the series of processing.

[0107] If neither of the conditions in step S1004 and step S1005 apply (steps S1004, S1005: No), the process moves to step S1007, where the current sampling time nT and the sampling time are determined. It is determined whether (m+k)T are equal (step S1007). Here, the sampling time (m+k)T is the time at which either positive or negative changes are recorded continuously for a stable predetermined number of samplings, starting from a certain sampling time mT. Refers to sampling time. And step S1 In the judgment of 007, if the current sampling time nT and the sampling time (m+k)d are equal (step S1007: Yes), the series of processing ends.

[0108] Next, if the current sampling time nT and the sampling time (m+k)T are not equal (Step S 1007: No), then the cumulative recording in the ring buffer at the current sampling time nT is performed. It is determined whether or not the accumulated right output value 0 rn is equal to the accumulated left output value I 0 1n | (since this is a negative output, the absolute value is compared) (step S1008). At this time, the prerequisite is that the cumulative right output value 0 rn and the cumulative left output value I 0 1η I are greater than 0. This condition is to prevent 0 rn= | θ ΐη I from rotating 360° by turning only to the right or only to the left.

[0109] In the judgment in step S1008, if the cumulative right output value Θ rn and the cumulative left output value I 0 In I at the current sampling time nT are not equal (step S1008: No), the series of processing is terminated. do. If the cumulative right output value Θ rn and the cumulative left output value I 0 1η I at the current sampling time nT are equal (step S 1008 : Yes), the left and right detection error (gain difference) of the angular velocity is corrected. In order to move on to the processing for this purpose, first, it is determined whether or not the right output value was the reference force when the sensor orientation Sam was recorded at the sampling time mT (step S1009). Step S1009 checks whether the amount of change when confirming stable output was positive (right) or negative (left), and corrects the bending direction opposite to the reference based on either the left or right output value. This is a process for determining whether to update coefficients.

[0110] In step S1009, if the right output value is not the reference (step S1009: No), the process moves to step S1065 (see Figure 16), and when the sensor orientation Sam is recorded at sampling time mT, It is determined whether the left output value is the reference force or not (step S 1065). If the right output value is the reference (step S1009: Yes), then it is determined whether the GPS bearing Gbn at the current sampling time nT is smaller than the GPS bearing Gam at the sampling time mT!/, or not ( step S1010).

[0111] If the GPS bearing Gbn at the current sampling time nT is not smaller than the GPS bearing Gam at the sampling time mT (step S1010: No), the process moves to step S1024 (see Figure 12), and the current sampling time Processing is performed to check the magnitude relationship between the GPS bearing Gbn at nT and the GPS bearing Gam at sampling time mT. this time If the GPS azimuth Gbn at the sampling time nT is smaller than the GPS azimuth Gam at the sampling time mT (step SIOIO: Yes), then the sensor azimuth Sbn at the current sampling time nT is smaller than the sensor azimuth Sam at the sampling time mT Vヽ(underrun) or not (step S1011).

[0112] In step S1011, if the sensor orientation Sbn at the current sampling time nT is smaller than the sensor orientation Sam at the sampling time mT (step S1011: No), the correction coefficient is not updated, so the series of processing end. If the sensor orientation Sbn at the current sampling time nT is smaller than the sensor orientation S am at the sampling time mT!/ヽ (underrun) (step S1011: Yes), the process moves to the flowchart in Figure 11, and then the previous It is determined whether the sensor orientation Sbn' at sampling time n'T is larger (overrun) than the sensor orientation Sam at sampling time m, T (step S1012).

[0113] In step S1012, if the sensor orientation Sbn, at the previous sampling time n'T is not larger than the sensor orientation Sam' at the sampling time m'T (step S1012:No), then the next sampling time It is determined whether the sensor orientation Sbn' at sampling time m, 'T' is greater than the sensor orientation Sam' ' at sampling time m, 'T' (step S1013). Here, if the sensor orientation Sbn' at the sampling time n' and T before the previous sampling time is not larger than the sensor orientation Sam' ' at the sampling time m' 'T (step S10 13: No), the left and right gain difference correction coefficient diverges. Since this is the state, the convergence-divergence state flag is set to 0 (step S1014).

[0114] Here, flags will be explained. The flags are F Θ r used for right gain difference correction and F θ 1 used for left gain difference correction, respectively. Based on the comparison of the sensor orientation Sbn at sampling time nT and the sensor orientation Sam at sampling time mT, each case is divided into four cases, and the initial state is cleared to "0". The flag represents the state at the next adjustment (correction). For example, if the current adjustment (correction) is a left gain difference correction, and the current adjustment was in an underrun condition (Sbn, Sam) and the previous adjustment was in an overrun condition (Sam, Sbn,), the correction amount is -0. 2%. So the flags F Θ 11 and F Θ 12 are “1 ", and the left gain difference correction coefficient G1 is in a converged state. Therefore, the convergence-divergence state flag of the "left and right gain difference correction coefficient" is set to "1", and the left gain difference correction coefficient G1 is in a converged state. Therefore, when the next adjustment (correction) is to correct the right gain difference, it means that the left gain difference correction coefficient G1 is in a converged state, and when the next adjustment (correction) is to correct the left gain difference, it means that the previous adjustment is underrun. In the state (Sbn'<Sam'), the previous time becomes an overrun state (Sam', <Sbn', ).

[0115] Furthermore, if the next adjustment (correction) is an underrun condition (Sbn<Sam) when correcting the left gain difference, the correction amount will be 0.1%, and flags F Θ 11 and F Θ 12 will be set to "0. ”, the left gain difference correction coefficient G1 remains in the converged state even if the subsequent adjustments (corrections) are right gain difference correction until the next and subsequent adjustments (corrections) are corrected for the left gain difference. This means that the state when the left gain difference correction is performed one after another is an underrun state (Sb n, < Sam') the previous time, and an underrun state (Sbn,, < Sam', ) two times before. Become. Then, when the next adjustment (correction) is to correct the left gain difference, if this time there is an underrun condition (Sbn<Sam), the correction amount will be 10.4%, and flags F Θ 11 and F Θ 12 have already been set to " Since the left gain difference correction coefficient G1 is cleared to "0" and is in a divergent state, the convergence-divergence state flag of the "left and right gain difference correction coefficient" is cleared to "0" and becomes a divergent state. Note that the flags F 0 rl and F 0 r2 are processed in the same way, but the correction amounts used are +0. 2%, +0. 1%, and +0. 4%, respectively. .

[0116] Also, for example, when the current adjustment (correction) is to correct the left gain difference, if the current adjustment (correction) is in an overrun state (Sam< Sbn) and the previous one was in an underrun state (Sbn' < Sam'), the amount of correction is + 0. 2%, flags F Θ 13 and F Θ 14 are set to "1", and the left gain difference correction coefficient G1 is in a converged state, so the convergence-divergence state flag of "left and right gain difference correction coefficient" is It is set to “1” and enters the convergence state. Therefore, when the next adjustment (correction) is right gain difference correction, the left gain difference correction coefficient G1 is in a converged state, and when the next adjustment (correction) is left gain difference correction, the previous state is In an overrun state (Sam, < Sam', ), the previous time becomes an underrun state (Sbn', < Sam', ).

[0117] Furthermore, if the next adjustment (correction) is to correct the left gain difference and this time is in an overrun state (Sam + Sbn), the correction amount will be + 0.1%, and flags F Θ 13 and F Θ 14 will be set to " Even if it is cleared to 0, subsequent adjustments (corrections) will continue until the left gain difference correction is performed. Even when the adjustment (correction) is correcting the right gain difference, the left gain difference correction coefficient G1 indicates that it is in a converged state. < Sbn, ), the overrun state occurred two times before (Sam,, < Sbn,, ). Then, when the next adjustment (correction) is to correct the left gain difference, if this time there is an underrun condition (Sbn<Sam), the correction amount will be +0.4%, and flags F Θ 13 and F Θ 14 have already been set. Since it is cleared to "0" and the left gain difference correction coefficient G1 is in a divergent state, the convergence-divergence state flag of the "left and right gain difference correction coefficient" is cleared to "0" and becomes a divergent state. Note that in the case of the flags F Θ r3 and F Θ r4, the forces are processed in the same way, and the correction amounts used are 0. 2%, -0. 1%, and -0. 4%, respectively.

[0118] Returning to the explanation of the flowchart, since the convergence-divergence state flag was set to 0 in step S1014, the correction amount α is then set to 0.4% (step S1015). Next, in order to update the current left gain difference correction coefficient, the left gain difference correction coefficient Gin at sampling time nT is set to a value obtained by subtracting a from the previous left gain difference correction coefficient Gin−1 (step S1022). It is determined that this is an underrun state (step S 1023), and the series of processing ends.

[0119] Returning to the judgment in step S1012, if the sensor orientation Sbn' at the previous sampling time n' T is larger than the sensor orientation Sam' at the sampling time m' T (step S1012: Yes), the previous An overrun state occurs, and the flag F 0 11 = 1 is set (step S1018). Subsequently, the correction amount α is set to 0.2% (step S 1019). The sensor orientation Sbn' at the previous sampling time n' T is not greater than the sensor orientation Sam' at the sampling time m' T (Step S 1012 : No). If the sensor orientation at sampling time m,, T is larger than Sa m' ' (step S1013: Yes), the previous time is in an overrun state, the flag F Θ 11 = 0 is set (step S 1016), and the correction amount α =0.1% (step S 1017).

[0120] When the correction amount is set in step S1017 or step S1019, at least one of the flags F 0 rl, F 0 r2, F Θ r3, and F 0 r4 is set to “1”. It is determined whether or not (step S1020). The processing in this step is based on the left output value. As a result of the right gain difference correction process, it is determined whether or not the current right gain difference correction coefficient Grn is in a converged state in the previous or two previous processes. Refer to the four flags set above.

[0121] In step S1020, if at least one of the flags F Θ ΓΙ, F 0 r2, F Θ r3, F Θ r4 is “1” (Step S1020: Yes), the left and right gain difference correction coefficient is in a converged state. It is determined that there is, the convergence/divergence state flag is set to 1 (step S1021), and the process moves to update processing in step S1022. If all of the flags F Θ ΓΙ, F 0 r2, F 0 r3, and F 0 r4 are "0" (step S1020: No), the process moves to the update process of step S1022 without setting the flags of step S1021. do.

[0122] Next, returning to FIG. 10, in step S1010, the process is performed when the GPS bearing Gbn at the current sampling time nT is not smaller than the GPS bearing Gam at the sampling time mT (Step S1010: No). This will be explained using the flowchart in Figure 12. First, it is determined whether the GPS bearing Gbn at the current sampling time nT is equal to the GPS bearing Gam at the sampling time mT (step S1024). If the GPS bearing Gbn at the current sampling time nT is not equal to the GPS bearing Gam at the sampling time mT (step S1024: No), the process moves to step S1051 (see FIG. 14).

[0123] If the GPS orientation Gbn is equal to the GPS orientation Gam (step S 1024 : Yes), then the sensor orientation Sbn at the current sampling time nT is smaller than the sensor orientation Sam at the sampling time mT. Judgment (Step S1025), Judgment (Step S1026) as to whether the sensor orientation Sbn' at the previous sampling time n'T is greater than the sensor orientation Sa m, at the sampling time m'T, and the sampling time n' before the previous one. , it is determined whether the sensor orientation Sbn'' at sampling time m''T is greater than the sensor orientation Sam'' at sampling time m''T (step S1027).

[0124] The sensor orientation Sbn at the current sampling time nT is smaller than the sensor orientation Sam at the sampling time mT (Step S 1025 : Yes), and the sensor orientation Sbn' at the previous sampling time n'T is smaller than the sensor orientation Sam at the sampling time m'. The sensor orientation at T is not greater than Sam' (Step S 1026 : No), and the sensor orientation at T If n' is not larger than the sensor orientation Sam" at the sampling time m''T (Step S1027: No), it is determined that the left and right gain difference correction coefficients are in a divergent state, and the convergence-divergence state flag is set to 0. (Step S1028).Therefore, the correction amount j8 is set to 0.4% (Step S1029).

[0125] In step S1025, if the sensor orientation Sbn at the current sampling time nT is not smaller than the sensor orientation Sam at the sampling time mT (step S1025: No), the process moves to step S1038 (see Figure 13), and this time , a process is performed to determine whether the sensor orientation Sbn at the current sampling time nT is larger than the sensor orientation Sam at the sampling time mT (step S1038).

[0126] In step S1026, if the sensor orientation Sbn, at the previous sampling time n, T is larger than the sensor orientation Sam' at the sampling time m'T (step S1026: Yes), the previous time is in an overrun state, and the flag F Θ12 = 1 is set (step S1032), and the positive amount j8 is set as 0.2% (step S1033). Similarly, in step S1027, if the sensor orientation Sbn'' at the sampling time n' 'T before the previous time is larger than the sensor orientation Sam'' at the sampling time m' 'T' (step S1027: Yes), is in an overrun state, the flag F Θ 12 = 0 is set (step S 1030), and the correction amount β = 0.1% (step S 1031).

[0127] When the correction amount is set in step S 1031 or step S 1033, at least one of the flags F 0 rl, F 0 r2, F Θ r3, F 0 r4 is set to “1”. It is determined whether or not there is one (step S1034). The processing in this step is based on the left output value as in step S1020 in Figure 11, and the current right gain difference correction coefficient Grn is in the convergence state in the previous or the previous processing as a result of the right gain difference correction processing. It makes a judgment as to whether the power is present or not, and refers to the above four flags set in the previous process or the process before the previous process.

[0128] In step S1034, if at least one of the flags F 0 rl, F 0 r2, F Θ r3, F Θ r4 is "1" (step S1034: Yes), the left and right gain difference correction coefficient is in a converged state. It is determined that there is, the convergence/divergence state flag is set to 1 (step S1035), and the process moves to update processing in step S1036 (see FIG. 13). All of the flags F Θ ΓΙ, F 0 r2, F 0 r3, F 0 r4 are " 0" (step S1034: No), the flag is not set in step S1035 and the process moves to the update process in step S1036 (see FIG. 13).

[0129] Next, the flowchart shown in FIG. 13 will be explained. First, when the processing in step S1029, step S1034 (in case of No), or step S1035 is completed, in order to update the current left gain difference correction coefficient, the left gain difference correction coefficient Gin at sampling time nT is updated. is set as a value obtained by subtracting β from the previous left gain difference correction coefficient Gin-1 (step S1036), it is determined that this time is an underrun state (step S1037), and the series of processing is terminated.

[0130] Next, using the flowchart shown in FIG. 12, if it is determined in step S1025 that the sensor orientation Sbn at the current sampling time nT is not smaller than the sensor orientation Sam at the sampling time mT (Step S1025 : No), it is then determined whether the sensor orientation Sbn at the current sampling time nT is greater than the sensor orientation Sam at the sampling time mT (step S1038). If the sensor orientation Sbn at the current sampling time nT is larger than the sensor orientation Sam at the sampling time mT (step S1038: No), the series of processes ends.

[0131] In step S1038, if the sensor orientation Sbn at the current sampling time nT is larger than the sensor orientation Sam at the sampling time mT (Step S1038: Yes), the sensor orientation Sbn' at the previous sampling time n'T is the sampling time Judging whether the sensor orientation Sam' at m'T is smaller than (step S1039) and determining whether the sensor orientation Sbn'' at the sampling time n' 'T before the previous time is smaller than the sensor orientation Sam' at the sampling time m' 'T, . A determination is made as to whether or not it is small (step S 1040).

[0132] If the sensor orientation Sbn' at the previous sampling time n'T is not smaller than the sensor orientation Sam at the sampling time m'T (Step S 1039: No), the sensor orientation Sbn at the sampling time n' 'T before the previous If ' ' is not smaller than sensor orientation Sam' ' at sampling time m' 'T' (step S 1040: No), it is determined that the left and right gain difference correction coefficients are in a divergent state, and the convergence-divergence state flag is set to 0. (Step S1041). Therefore, the correction amount j8 is set to 0.4% (step S 1042).

[0133] In step S1039, the sensor orientation Sbn at the previous sampling time n'T, If is smaller than the sensor orientation Sam' at sampling time m'T (step S1039: Yes), the process moves to step S1045 (see Figure 14), the previous time is in an underrun state, and the flag F Θ 13 = 1 (Step S1045), and the correction amount j8 is set to =0.2% (Step S1046). Similarly, returning to Fig. 13, in step S1040, if the sensor orientation Sbn, ' at the sampling time n, 'T before the previous time is smaller than the sensor orientation Sam'' at the sampling time m''T' (step S1040: Yes), , the previous time was in an underrun state, and the flag F Θ 13 = 0 is set (step S1043), and the correction amount j8 is set to 0.1% (step S1044).

[0134] When the correction amount is set in step S 1044 or step S 1046, at least one of the flags F 0 rl, F 0 r2, F Θ r3, F 0 r4 is set to “1”. It is determined whether or not there is one (step S1047). The processing in this step is based on the left output value as in step S1020 in Figure 11, and the current right gain difference correction coefficient Grn is in the convergence state in the previous or the previous processing as a result of the right gain difference correction processing. It makes a judgment as to whether the power is present or not, and refers to the above four flags set in the previous process or the process before the previous process.

[0135] In step S1047, if at least one of the flags F 0 rl, F 0 r2, F Θ r3, F Θ r4 is "1" (step S1047: Yes), the left and right gain difference correction is performed. It is determined that the coefficient is in a converged state, the convergence-divergence state flag is set to 1 (step S1048), and the process moves to update processing in step S1049. If all of the flags F Θ ΓΙ, F 0 r2, F 0 r3, and F 0 r4 are "0" (step S 1047 : No), the update process in step S 1049 is performed without setting the flags in step S 1048. to move to.

[0136] Next, in order to update the current left gain difference correction coefficient, the left gain difference correction coefficient Gin at sampling time nT is added by β from the previous left gain difference correction coefficient Gin−1. value (step S 1049), determines that this is an overrun state (step S 1050), and ends the series of processing.

[0137] Next, using the flowchart shown in FIG. 12, if in step S1024 the GPS bearing Gbn at the current sampling time nT is not equal to the GPS bearing Gam at the sampling time mT (step S1024: No), The flowchart shown in Figure 14 V, it is determined whether the GPS bearing Gbn at the current sampling time nT is greater than the GPS bearing Gam at the sampling time mT (step S1051). If the GPS azimuth Gbn at the current sampling time nT is greater than the GPS azimuth Ga m at the sampling time mT (Step S1051: Yes), then the sensor azimuth Sbn at the current sampling time nT is the sensor azimuth at the sampling time mT. It is determined whether or not it is larger than Sam (step S 1052).

[0138] If the GPS azimuth Gbn at the current sampling time nT is not greater than the GPS azimuth Gam at the sampling time mT (Step S1051: No), or if the sensor azimuth Sbn at the current sampling time nT is the sensor azimuth at the sampling time mT. If it is not larger than Sam (step S1052: No), the series of processing ends. If the GPS bearing Gbn at the current sampling time nT is larger than the GPS bearing Gam at the sampling time mT (step S1051: Yes), and the sensor bearing S bn at the current sampling time nT is larger than the sensor bearing Sam at the sampling time mT (step S 1052: Yes) then moves to the flowchart shown in Figure 15, and first determines whether the sensor orientation Sbn' at the previous sampling time n'T is smaller than the sensor orientation Sa m, at the sampling time m'T. (Step S1053) and determine whether the sensor orientation Sbn' ' at the sampling time n, , d before the previous time is smaller than the sensor orientation Sam' ' at the sampling time m' 'T (Step S1054). .

[0139] If the sensor orientation Sbn' at the previous sampling time n'T is not smaller than the sensor orientation Sam at the sampling time m'T (Step S 1053: No), the sensor orientation Sbn at the sampling time n' 'T before the previous one is not smaller than the sensor orientation Sam at the sampling time m'T. If ' ' is not smaller than sensor orientation Sam' ' at sampling time m' 'T' (step S 1054 : No), it is determined that the left and right gain difference correction coefficients are in a divergent state, and the convergence-divergence state flag is set to 0. (Step S1055). Therefore, the correction amount γ is set to 0.4% (step S1056).

[0140] In step S1053, if the sensor orientation Sbn, at the previous sampling time n'T is smaller than the sensor orientation Sam' at the sampling time m'T (step S1053: Yes), the previous time is in an underrun state, and the flag F Θ 14 = 1 is set (step S 1059), and the correction amount T =0.2% is set (step S 1060). Similarly, in step S1054 If the sensor orientation Sbn'' at the sampling time n''T of the sampling time before the previous time is smaller than the sensor orientation Sam'' at the sampling time m, 'T' (step S1054: Yes), the previous sampling time is in an underrun state. The flag F Θ 14 = 0 is set (step S1057), and the correction amount γ is set to 0.1% (step S1058).

[0141] When the correction amount is set in step S1058 or step S1060, it is next determined whether at least one of the flags F0rl, F0r2, FΘr3, and F0r4 is set to "1". (Step S 1061). The processing in this step is based on the left output value as in step S1020 in Figure 11, and the current right gain difference correction coefficient Grn is in the convergence state in the previous or the previous processing as a result of the right gain difference correction processing. It makes a judgment as to whether the power is present or not, and refers to the above four flags set in the previous process or the process before the previous process.

[0142] In step S1061, if at least one of the flags F 0rl, F0 r2, F Θ r3, F Θ r4 is “1” (Step S 1061: Yes), the left and right gain difference correction coefficient is in a converged state, sets the convergence-divergence state flag = 1 (step S1062), and moves to the update process of step S1063. If all of the flags FΘΓΙ, F0r2, F0r3, F0r4 are "0" (step S1061: No), the process moves to the update process of step S1063 without setting the flags of step S1062.

[0143] Next, in order to update the left gain difference correction coefficient this time, the left gain difference correction coefficient Gin at sampling time nT is added by γ from the previous left gain difference correction coefficient Gin−1. value (step S 1063), determines that this is an overrun state (step S 1064), and ends the series of processing.

[0144] Next, the flowchart shown in FIG. 16 will be explained. First, in step S1009 (see FIG. 10), when the sensor orientation Sam is detected at the sampling time mT, the process will be described when the right output value is less than the reference value (step S1009: No). First, when the sensor orientation Sam is detected at the sampling time mT, it is determined whether the left output value is the reference force or not (step S1065). If the left output value exceeds the reference value (step S1065: No), the series of processing ends.

[0145] In step S 1065, if the left output value is the reference (step S 1065: Yes) Next, determines whether the GPS bearing Gbn at the current sampling time nT is smaller than the GPS bearing Gam at the sampling time mT (step S 1066). If the GPS bearing Gbn at the current sampling time nT is not smaller than the GPS bearing Gam at the sampling time mT (step S1066: No), the process moves to step S1080 (see Figure 17).

[0146] In step S1066, if the GPS bearing Gbn at the current sampling time nT is smaller than the GPS bearing Gam at the sampling time mT (Step S1066: Yes), then the sensor bearing Sbn at the current sampling time nT is Determining whether the sensor orientation Sbn' at the sampling time m'T is smaller than the sensor orientation Sam at the sampling time m'T (step S1067) and determining whether the sensor orientation Sbn' at the previous sampling time n'T is greater than the sensor orientation Sam at the sampling time m'T. (Step S1068), and it is determined whether the sensor orientation Sbn' at the sampling time n', T before the previous sampling time is greater than the sensor orientation Sam, at the sampling time m, T (Step S1069).

[0147] The sensor orientation Sbn at the current sampling time nT is smaller than the sensor orientation Sam at the sampling time mT (Step S 1067 : Yes), and the sensor orientation Sbn' at the previous sampling time n'T is smaller than the sensor orientation Sam at the sampling time m'. If the sensor orientation at T is not greater than Sam' (step S 1068 : No), and the sensor orientation Sb n' at T is not greater than the sensor orientation Sam' at sampling time m' 'T (step S 1068 : No), Step S1069 :No), it is determined that the left and right gain difference correction coefficient is in a divergent state, and the convergence-divergence state flag is set to 0 (step S1070).Therefore, the correction amount α is set to 0.4%. (Step S 1071).

[0148] In step S1067, if the sensor orientation Sbn at the current sampling time nT is smaller than the sensor orientation Sam at the sampling time mT!/, (step S1067: No), the series of processing ends. In step S1068, if the sensor orientation Sbn' at the previous sampling time n'T is larger than the sensor orientation Sam' at the sampling time m'T (step S1068: Yes), the previous time is in an overrun state, and the flag F Θ r 1 = 1 (step S1074), and the correction amount α =0.2% (step S1075). Similarly, in step S 1069, the sensor at the sampling time η', T before the previous one is If the sensor orientation Sbn' is larger than the sensor orientation Sam' at the sampling time m, 'T' (step S1069: Yes), the previous time is in an overrun state, and the flag FΘ rl = 0 is set (step S1072). , the correction amount α is set to 0.1% (step S1073).

[0149] When the correction amount is set in step S 1073 or step S 1075, it is next determined whether at least one of flags F 011, F012, F013, and F 014 is set to "1". (Step S1076). The process in this step is based on the right output value, and it is determined whether or not the current left gain difference correction coefficient Gin is in a converged state in the previous or two previous processes based on the results of the left gain difference correction process. The above four flags set in the previous process or the process before the previous process are referenced.

[0150] In step S1076, if at least one of the flags F Θ11, F012, F Θ 13, F Θ 14 is "1" (step S1076: Yes), it is determined that the left and right gain difference correction coefficients are in a converged state. It is determined, the convergence-divergence state flag is set to 1 (step S1077), and the process moves to the update process of step S1078. If all of the flags F Θ11, F012, F013, and F014 are "0" (step S 1076: No), the process moves to the update process of step S 1078 without setting the flags of step S 1077.

[0151] Next, in order to update the current right gain difference correction coefficient, the right gain difference correction coefficient Gm at sampling time nT is added by a from the previous right gain difference correction coefficient Gm−1. (Step S1078), it is determined that this time is an underrun state (Step S1079), and the series of processing is ended.

[0152] Next, using the flowchart shown in Figure 17, it is determined in step S1066 (see Figure 16) that the GPS bearing Gbn at the current sampling time nT is not smaller than the GPS bearing Gam at the sampling time mT. The processing in the case (Step S 1066: No) will be explained. First, it is determined whether the GPS bearing Gbn at the current sampling time nT is equal to the GPS bearing Gam at the sampling time mT (step S1080). If the GPS bearing Gbn at the current sampling time nT is not equal to the GPS bearing Gam at the sampling time mT (step S1080: No), the process moves to step S1107 (see Figure 19).

[0153] The GPS direction Gbn at the current sampling time nT is If it is equal to the GPS bearing Gam (Step S1080: Yes), then it is determined whether the sensor bearing Sbn at the current sampling time nT is smaller than the sensor bearing Sam at the sampling time mT (Step S1081). Determining whether the sensor orientation Sbn' at the previous sampling time n'T is larger than the sensor orientation Sam' at the sampling time m'T (step S 1082), and determining whether the sensor orientation Sbn' at the sampling time n''T before the previous one is greater than the sensor orientation Sbn' at the sampling time m'T. It is determined whether or not ' is greater than sensor orientation Sam'' at sampling time m''T (step S 1083).

[0154] The sensor orientation Sbn at the current sampling time nT is smaller than the sensor orientation Sam at the sampling time mT (step S1081: Yes), and the sensor orientation Sbn' at the previous sampling time n'T is smaller than the sensor orientation Sam at the sampling time m'T. If the sensor orientation Sb n' at sampling time m' 'T is not greater than the sensor orientation Sam' at the sampling time m' 'T (step S 1082 : No), and the sensor orientation Sb n' at the sampling time n, ,T before the previous time S1083:No), it is determined that the left and right gain difference correction coefficient is in a divergent state, and the convergence-divergence state flag is set to 0 (step S1084).Therefore, the correction amount j8 is set to 0.4% ( Step S 1085).

[0155] In step S1081, if the sensor orientation Sbn at the current sampling time nT is not smaller than the sensor orientation Sam at the sampling time mT (step S1081: No), the process moves to step S1094 (see FIG. 18). In step S1082, if the sensor orientation Sbn' at the previous sampling time n'T is greater than the sensor orientation Sam' at the sampling time m'T!/, (step S1082: Yes), the previous time is an overrun state. Therefore, the flag F Θ r2 = l is set (step S1088), and the correction amount j8 =0. 2% is set (step S1089). Similarly, in step S1083, if the sensor orientation Sbn'' at the sampling time n' 'T before the previous one is larger than the sensor orientation Sam'' at the sampling time m' 'T (step S1083: Yes), the previous sampling time is over. A run state is entered, the flag F Θ r2 = 0 is set (step S1086), and the correction amount j8 is set to 0.1% (step S1087).

[0156] When the correction amount is set in step S 1087 or step S 1089, at least one of the flags F 0 11, F 0 12, F 0 13, and F 0 14 is set to “1”. There is It is determined whether or not (step S1090). The processing in this step is based on the right output value as in step S1076 in Fig. 16, and the current left gain difference correction coefficient Gin is in the convergence state in the previous or two previous processing as a result of the left gain difference correction processing. It makes a judgment as to whether the power is present or not, and refers to the above four flags set in the previous process or the process before the previous process.

[0157] In step S1090, if at least one of the flags F Θ 11, F 0 12, F Θ 13, F Θ 14 is “1” (step S1090: Yes), the left and right gain difference correction coefficient is in a converged state. It is determined that there is, the convergence/divergence state flag is set to 1 (step S1091), and the process moves to the update process of step S1092. If all of the flags F Θ 11, F 0 12, F 0 13, F 0 14 are "0" (Step S1090: No), proceed to the update process of Step S1092 without setting the flags of Step S1091. .

[0158] Next, in order to update the current right gain difference correction coefficient, the right gain difference correction coefficient Gm at sampling time nT is added by β from the previous right gain difference correction coefficient Gm−1. (Step S1092), it is determined that the current state is an underrun state (Step S1093), and the series of processing ends.

[0159] Next, using the flowchart shown in Figure 18, it is determined in step S1081 (see Figure 17) that the sensor orientation Sbn at the current sampling time nT is not smaller than the sensor orientation Sam at the sampling time mT. (Step S1081: No). First, it is determined whether the sensor orientation Sbn at the current sampling time nT is greater than the sensor orientation Sam at the sampling time mT!/ (step S1094). If the sensor orientation Sbn at the current sampling time nT is not larger than the sensor orientation Sam at the sampling time mT (step S1094: No), the series of processes ends.

[0160] In step S1094, if the sensor orientation Sbn at the current sampling time nT is larger than the sensor orientation Sam at the sampling time mT (Step S1094: Yes), the sensor orientation Sbn' at the previous sampling time n'T is the sampling time It is determined whether the sensor orientation at m'T is smaller than Sam' (step S1095) and the sensor orientation Sbn' at the sampling time n''T before the previous time is smaller than the sensor orientation at the sampling time m''T. A determination is made as to whether the sensor orientation is smaller than Sam, (step S1096).

[0161] If the sensor orientation Sbn' at the previous sampling time n'T is not smaller than the sensor orientation Sam at the sampling time m, d (Step S 1095: No), the sensor orientation Sbn at the previous sampling time n' 'T If ' ' is not smaller than sensor orientation Sam' ' at sampling time m' 'T' (Step S 1096 : No), it is determined that the left and right gain difference correction coefficients are in a divergent state, and the convergence-divergence state flag is set to 0. (Step S1097). Therefore, the correction amount j8 is set to 0.4% (step S1098).

[0162] In step S1095, if the sensor orientation Sbn, at the previous sampling time n, T is smaller than the sensor orientation Sam' at the sampling time m'T (step S1095: Yes), the previous time is in an underrun state, and the flag F 0 r3 = l (step S1101), and the positive amount j8 =0.2% (step SI 102). Similarly, in step S1096, if the sensor orientation Sbn'' at the sampling time n''T before the previous one is smaller than the sensor orientation Sam, at the sampling time m,,T (step S1096: Yes), times is in an underrun state, the flag F Θ r3 = 0 is set (step S1099), and the correction amount j8 =0.1% is set (step S1100).

[0163] When the correction amount is set in step S1100 or step S1102, it is next determined whether at least one of the flags F 0 11, F 0 12, F 0 13, and F 0 14 is set to “1”. It is determined whether or not (step S1103). The processing in this step is based on the right output value as in step S1076 in Fig. 16, and the current left gain difference correction coefficient Gin is in the convergence state in the previous or two previous processing as a result of the left gain difference correction processing. It makes a judgment as to whether the power is present or not, and refers to the above four flags set in the previous process or the process before the previous process.

[0164] In step S1103, if at least one of the flags F Θ 11, F 0 12, F Θ 13, F Θ 14 is “1” (Step S1103: Yes), the left and right gain difference correction coefficient is in a converged state. It is determined that there is, the convergence/divergence state flag is set to 1 (step S1104), and the process moves to update processing in step S1105. If all of the flags F Θ 11, F 0 12, F 0 13, F 0 14 are "0" (Step S 1103 : No), the update processing in Step S 1105 is performed without setting the flags in Step S 1104. to move to. [0165] Next, in order to update the current right gain difference correction coefficient, the right gain difference correction coefficient Gm at sampling time nT is the value obtained by subtracting β from the previous right gain difference correction coefficient Gm−1. (Step S1105), determines that this is an overrun state (Step S1106), and ends the series of processing.

[0166] Finally, using the flowchart shown in Figure 19, in step S1080 (see Figure 17), it is determined that the GPS bearing Gbn at the current sampling time nT is not equal to the GPS bearing Gam at the sampling time mT!/ , the processing in the case (step S1080: No) will be explained. First, it is determined whether the GPS bearing Gbn at the current sampling time nT is larger than the GPS bearing Gam at the sampling time mT (step S1107). If the GPS azimuth Gbn at the current sampling time nT is not larger than the GPS azimuth G am at the sampling time mT (step S1107: No), the series of processes ends.

[0167] If the GPS bearing Gbn at the current sampling time nT is greater than the GPS bearing Gam at the sampling time mT (Step S1107: Yes), then the sensor bearing Sbn at the current sampling time nT is set to the sampling time mT. A determination is made as to whether the sensor orientation is larger than Sa m (step S1108). If the sensor orientation Sbn at the current sampling time nT is not larger than the sensor orientation Sam at the sampling time mT (step S1108: No), the series of processes ends.

[0168] In step S1108, if the sensor orientation Sbn at the current sampling time nT is greater than the sensor orientation Sam at the sampling time mT!/ (Step S1108: Yes), the sensor orientation Sbn' at the previous sampling time n'T is smaller than the sensor orientation Sam' at the sampling time m'T (step S1109), and the sensor orientation Sbn' at the sampling time n' 'T before the previous time is determined to be smaller than the sensor orientation Sam' at the sampling time m' 'T. , , is smaller than (step S1110).

[0169] If the sensor orientation Sbn' at the previous sampling time n'T is not smaller than the sensor orientation Sam' at the sampling time m'T (Step S 1109: No), the sensor orientation Sbn at the previous sampling time n''T If '' is not smaller than sensor orientation Sam'' at sampling time m''T (Step S1110: No), it is determined that the left and right gain difference correction coefficients are in a divergent state, and the convergence-divergence state flag is set to 0. (step Sl lll). However, Therefore, the correction amount γ is set to 0.4% (step S1112).

[0170] In step S1109, if the sensor orientation Sbn, at the previous sampling time n, T is smaller than the sensor orientation Sam' at the sampling time m' T (step SI 109: Yes), the previous time is in an underrun state, and the flag is set. F0r4=l is set (step S1115), and the positive amount T is set to 0.2% (step SI 116). Similarly, in step S1110, if the sensor orientation Sbn'' at the sampling time n' 'T before the previous one is smaller than the sensor orientation Sam'' at the sampling time m, 'T' (step S1110: Yes), times is in an underrun state, the flag F Θ r4 = 0 is set (step S1113), and the correction amount γ is set to 0.1% (step S1114).

[0171] When the correction amount is set in step S1114 or step S1116, it is next determined whether at least one of the flags F 011, F012, F013, and F 014 is set to "1" ( step S1117). The processing in this step is based on the right output value as in step S1076 in Fig. 16, and the current left gain difference correction coefficient Gin is in the convergence state in the previous or two previous processing as a result of the left gain difference correction processing. It makes a judgment as to whether the power is present or not, and refers to the above four flags set in the previous process or the process before the previous process.

[0172] In step S1117, if at least one of the flags F Θ11, F012, F Θ 13, F Θ 14 is “1” (step S1117: Yes), it is determined that the left and right gain difference correction coefficients are in a converged state. Then, the convergence-divergence state flag is set to 1 (step S1118), and the process moves to update processing in step S1119. If all of the flags FΘ11, F012, F013, and F014 are "0" (step S1117: No), the process moves to the update process of step S1119 without setting the flags of step S1118.

[0173] Next, in order to update the current right gain difference correction coefficient, the right gain difference correction coefficient Gm at sampling time nT is the value obtained by subtracting γ from the previous right gain difference correction coefficient Gm−1. (Step S1119), determines that this time is an overrun state (Step S1120), and ends the series of processing.

[0174] Through the processing described above, detection errors of the angular velocity sensor can be reduced by using either the currently updated left/right gain difference (sensitivity difference) correction coefficient Gin or Grn. A corrected sensor orientation with the difference removed can be calculated. As defined earlier, the detection error here refers to the difference in gain of the angular velocity sensor due to differences in the direction of the vehicle's turn.

This is the detection error due to (sensitivity difference). In other words, according to the first embodiment, since the detection error is calculated with high accuracy, the current overrun state or underrun state is accurately reflected in the setting of the correction coefficient. Therefore, error correction due to the left and right gain difference can be performed automatically and with high precision, and accurate sensor orientation and travel distance per unit time can be obtained, allowing the vehicle to be navigated accurately.

Example 2

[0175] Next, Example 2 of the present invention will be described. The second embodiment is realized using part of the hardware configuration described in the first embodiment. Therefore, the hardware configuration of the parts that are different from the first embodiment will be explained below.

[0176] In the azimuth calculation unit 313 and the correction processing unit 314 shown in FIG. Cases are divided based on the comparison results. Thereafter, in those cases, the cumulative values of positive and negative changes accumulated from the first time to the second time are compared.

[0177] Further, the adjustment (update) of the correction coefficient by the left gain difference correction coefficient adjustment processing section 410 and the right gain difference correction coefficient adjustment processing section 411 is performed by determining the amount of correction for the currently set correction coefficient. Update. For example, six types of correction amounts, such as ±0. 4%, ±0. 2%, and ±0. 1%, are used to calculate the difference between the sensor orientation Sam at the first time and the sensor orientation Sbn at the second time. When the GPS direction Gam at the first time is acquired and the GPS direction Gbn at the second time is compared, the cases are divided and the amount of positive change from the first time force to the second time is calculated. It is changed as needed based on the comparison result between the cumulative value and the cumulative value of the amount of negative change (the specific method of changing is explained in detail using flowcharts in FIGS. 22 to 26). This correction amount is changed by observing the magnitude of the positive and negative changes accumulated in the vehicle from the first time to the second time so that the gain value converges to a positive value. .

[0178] (Principle of direction calculation in Example 2)

FIG. 20 is a diagram illustrating the principle of azimuth calculation according to the second embodiment. In the diagram and table 600 shown in Figure 20, the horizontal axis represents time t, and the sampling period T is shown by the vertical line (dashed line). Ru. In addition, the upper row at the bottom of chart 600 for the sampling period T interval shows the number of samples (1 to η), and the lower row at the bottom of chart 600 shows the sampling time (0T to ηT) with 0T as the starting time. ing. The vertical axis represents the output range of the acceleration sensor, 0V to 5V, in the digital value unit [LSB]. For example, in the case of a 12-bit AZD converter, 0V to 5V is divided by 4096, resulting in 1.22mV/LSB.

[0179] Curve 601 is similar to Example 1. For example, when the sampling period T is 100 [ms], AZD is performed 20 times (at 5 ms intervals) in 100 [ms] using an external 12-bit AZD converter. It represents the output value when conversion is performed. Then, using the above formula (1), perform averaging processing for 100[ms], and every 100[ms] represents the average value gyn of the AZD conversion data of the output value of the angular velocity sensor for 100[ms]. .

[0180] Further, the angular velocity ω η can be calculated using the above equation (2). This angular velocity ω η is represented by one sampling of each of the ranges 602a, 602b, 602c shown by the rectangular lines and the ranges 603a, 603b shown by the rectangular lines shown in FIG. For example, range 602a shown with square lines represents 2 samples, range 602b represents 3 samples, range 602c represents 2 samples, range 603a represents 4 samples, and range 603b represents 2 samples. represents minutes.

[0181] The angular displacement amount Δ Θ at each sampling time is calculated by integrating the sampling times 1T to nT in the entire range indicated by these rectangular lines in order over the sampling period T for each sampling. ₈ 1 to Δ 0 gn are accumulated to the previous sensor orientation Θ g0 to Θ gn— 1 at each sampling time. By repeating this process for the number of sampling times for the entire range, the sensor orientation Θ gn can also be obtained for the entire range force shown by the rectangular line. Note that the range 602a to 602c shown by the square line represents the positive (right) angular displacement amount, and the range 603a to 603b represents the negative (left) angular displacement amount.

[0182] As shown in FIG. 20, when the vehicle is moved, the output value (gyn-gyO) of the angular velocity sensor constantly changes while showing positive and negative values. Therefore, in this embodiment, for example, when a negative change amount is recorded in the curve 601 shown in FIG. . In addition, the sensor orientation Sam (Θ 5) and the GPS orientation Gam (Θ 6) calculated at the sampling time mT are expressed as GP Azimuth unit circle expressed in the S orientation system is shown in 604. In the case of chart 600, since the negative amount of change is recorded k times in a row, the right gain difference is corrected based on the cumulative value of the angular displacement amount to the left.

[0183] When comparing the cumulative values of positive and negative changes from sampling time mT, the positive and negative changes are accumulated in the ring buffer for each sampling period T. Use cumulative value. In Example 2, sampling is performed after obtaining the GPS bearing Gam (Θ 6) at the sampling time mT until a sensor bearing equal to the sensor bearing Sam (Θ 5) calculated at the sampling time mT is calculated. Acquisition of GPS direction and accumulation of positive or negative changes in the accumulation ring buffer are continued every cycle T. As in the example shown in Figure 600, sampling time nT is detected at which a sensor orientation that is equal to sensor orientation Sam at sampling time mT is recorded. In other words, the sensor orientation Sbn (Θ 5) at the sampling time ηΤ is equal to the sensor orientation Sam (Θ 5). Also, shown on the vertical axis representing the sampling time nT is the azimuth unit circle showing the GPS azimuth Gbn ( Θ 7) and the sensor azimuth Sbn ( Θ 5) calculated at the sampling time nT in the GPS azimuth system. Shown below. In Example 2, first, the GPS directions Gam (Θ 6) and Gbn (Θ 7) at the sampling time mT and the sampling time nT are compared, and based on the comparison results, the magnitude of Gam and Gbn is determined. Next, among these cases, the cumulative value of positive changes from sampling time mT to sampling time nT Θ rn= (602b + 602c) and the cumulative value of negative changes I Θ In I = I ( 603a + 603b) | and as a result of the comparison, whether the cumulative value of positive changes in force 0 rn is in an overrun or underrun state from the cumulative value of negative changes I 0 1η I Determine the amount of correction for either the left or right gain difference correction coefficient G1 or Gr.

[0184] (Processing procedure for calculating direction in Example 2)

FIG. 21 is a flowchart showing an overview of the correction coefficient setting process in the second embodiment. The direction calculation unit 313 (see FIG. 3) calculates the direction using the correction coefficient set by the procedure described below. In the flowchart shown in Figure 21, first, the sensor orientation and GPS orientation are recorded every sampling period T (step S 2001).

[0185] Next, at each sampling period T, either the positive (right) or negative (left) sensor orientation is Cumulatively record the amount of change (output value ≠ 0) and the other amount of change (output value = 0) (Step S2

002). Here, the positive amount of change represents the right output value of the sensor orientation, and the negative amount of change represents the left output value of the sensor orientation.

[0186] Next, in the process in step S2002, it is determined whether the amount of change in either the positive (right) or negative (left) force has been continuously recorded k times of sampling (step S200

3). Here, wait for either the positive (right) or negative (left) change amount to be recorded ¾ times in a row, and if it is recorded (Step S2003: Yes), the positive (right) change is recorded. If the amount of change is recorded continuously, perform left gain difference correction. If negative (left) change amount is recorded continuously, perform right gain difference correction (Step S 2004). The sampling time mT at which the continuous change in the bending direction started is detected (Step S 2005).

[0187] Next, from the sampling time mT, at every sampling period T, either the positive (right) or negative (left) change amount (output value ≠ 0) and the other change amount (output value = 0) are calculated. Accumulate (step S2006). Next, after detecting sampling time mT in step S2005, it is determined whether a sensor orientation equal to the sensor orientation at sampling time mT has been recorded (step S2007). Here, wait until a sensor orientation equal to the sensor orientation at sampling time mT is recorded, and if it is recorded (step S2007: Yes), the sensor orientation is recorded equal to the sensor orientation at sampling time mT. Detect sampling time nT (step S 2008).

[0188] Note that the sensor orientation at sampling time mT is Sam ( 0 5), and the GPS orientation is Gam (

Θ 6), the sensor orientation at sampling time nT is represented by Sbn ( Θ 5), and the GPS orientation is represented by Gb η ( θ 7). Also, the cumulative value of positive changes at sampling time nT is expressed as Θ rn, and the cumulative value of negative changes is expressed as I 0 In I.

[0189] Next, the GPS azimuth Gam (Θ 6) at sampling time mT is compared with the GPS azimuth Gbn (Θ 7) at sampling time nT (step S 2009), and the sampling time mT force is also calculated up to sampling time nT. The cumulative value of positive changes Θ rn and the cumulative value of negative changes | Θ In | are compared (step S2010). Therefore, after steps S2009 and S2010 are performed, the correction amount is determined based on the comparison result (step S2011).

[0190] Finally, the correction coefficient G1 is calculated using the correction amount determined in step S 2011. adjusts either one of Gr (step S2012) and ends the series of processing. As explained above, by repeating the process of updating the correction coefficient, the correction coefficient approaches the converged value.

[0191] FIGS. 22 to 26 are flowcharts showing detailed procedures of the correction coefficient setting process in the second embodiment. In the flowchart shown in Figure 22, first, at the current sampling time nT, it is determined whether the GPS positioning state is a three-dimensional positioning state (step S1201), and then, the GPS speed data is determined to be 30 [kmZh]. It is determined whether the vehicle speed pulse speed is 30 [kmZh] or more (step S1 203).

[0192] At the current sampling time nT, if all the conditions in step S1201 to step S1203 are satisfied (step S1201 to step S1203: Yes), then the amount of change in the average angle of the GP S direction is It is determined whether the force is less than 0.3 [deg] (step S1204), and then the angular acceleration, which is the displacement amount of the angular velocity [degZs] calculated from the output of the angular velocity sensor, is 0.3 [deg/ s · s] or less (step S 1205).

[0193] At the current sampling time nT, if the conditions do not apply in each step from step S1201 to step S1203 (step S1201 to step S1203: No), or if the condition does not apply to each step from step S1201 to step S1203, or if the condition does not apply to each step from step S1201 to step S1203, or if the condition does not apply to each step from step S1201 to step S1203, or if the condition does not apply to each step from step S1201 to step S1203 (step S1201 to step S1203: No), or from step S1204 to step S If the conditions are satisfied in each step of 1205 (step S1204, SI 205: Yes), the process moves to step SI 206, and the positive and negative change amount (right and left output values) cumulative ring buffer is stored. All are cleared to zero (step S1206) and the series of processing ends.

[0194] If neither of the conditions in Step S 1204 and Step S 1205 apply!/, (Step S1204, SI 205: No), the process moves to the condition determination in Step S1207, and the current sampling time nT It is determined whether or not and sampling time (m+k)T are equal (step S1207). Here, the sampling time (m+k)T is the time at which either positive or negative changes are recorded continuously for a stable predetermined number of samplings, starting from a certain sampling time mT. Refers to sampling time. Then, in the judgment at step S1 207, if the current sampling time nT and the sampling time (m+k)d are equal (step S1207: Yes), the series of processing ends. [0195] Next, if the current sampling time nT and the sampling time (m+k)T are not equal (Step S 1207: No), then the sensor orientation Sbn at the current sampling time nT and the sampling It is determined whether the sensor orientation Sam at time mT is equal to U (step S1208). If it is determined in step S1208 that the sensor orientation Sbn at the current sampling time nT is not equal to the sensor orientation Sam at the sampling time mT (step S1208: No), the series of processes ends.

[0196] If the sensor orientation Sbn at the current sampling time nT is equal to the sensor orientation Sam at the sampling time mT (Step S 1208 : Yes), correct the left and right detection error (gain difference) of the angular velocity. In order to move on to the processing for this purpose, first, it is determined whether or not the right output value was the reference force when the sensor orientation Sam was recorded at the sampling time mT (step S1209). Step S1209 checks whether the amount of change when confirming stable output was positive (right) or negative (left), and corrects the bending direction opposite to the reference based on either the left or right output value. This is a process for determining whether to update coefficients.

[0197] In step S1209, if the right output value is not the reference (step S1209: No), the process moves to step S1238 (see Figure 25), and when the sensor orientation Sam is recorded at sampling time mT, It is determined whether the left output value is the reference force or not (step S 1238). If the right output value is the reference (Step S1209: Yes), then it is determined whether the GPS bearing Gbn at the current sampling time nT is smaller than the GPS bearing Gam at the sampling time mT (Step S1210). .

[0198] If the GPS bearing Gbn at the current sampling time nT is not smaller than the GPS bearing Gam at the sampling time mT (step S1210: No), the process moves to step S1224 (see Figure 24), and the current sampling time Processing is performed to check the magnitude relationship between the GPS bearing Gbn at nT and the GPS bearing Gam at sampling time mT. If the GPS azimuth Gbn at the current sampling time nT is smaller than the GPS azimuth Gam at the sampling time mT (step S1210: Yes), then the cumulative left output value I 0 1η recorded in the cumulative ring buffer at the current sampling time nT is It is determined whether | (since it is a negative output, the absolute value is compared) is smaller than the cumulative right output value Θ rn (underrun) or not (step S1211). At this time, the cumulative right output value is 0 m and the cumulative left output value I Θ The precondition is that In I is greater than 0. Note that, from now on, in the judgment of comparing the cumulative right output value 0 rn and the cumulative left output value I 0 1η I, it is a prerequisite that they are all larger than 0. This condition is to avoid comparing 0 rn and I 0 1η I by rotating 360° only by turning right or only turning left.

[0199] In step S1211, if the cumulative left output value I 0 In | is not smaller than the cumulative right output value Θ rn at the current sampling time ηΤ (step S1211: No), the correction coefficient is not updated. Finish the series of processing. If the cumulative left output value I 0 1η I is smaller than the cumulative right output value 0 rn at the current sampling time nT (underrun) (step S 1211 : Yes), the process moves to the flowchart shown in FIG. 23, and first, At the previous sampling time n'T, the cumulative left output value I 0 1η, I is larger than the cumulative right output value 0 rn' (over one run) or not (step S1212), and the sampling time n' before the previous one is determined. At 'T, it is determined whether the cumulative left output value I θ ΐη" I is larger (overrun) than the cumulative right output value θ πι" (step S1213).

[0200] In step S1212, the cumulative left output value I Θ In' at the previous sampling time n'T

If I is not larger than the cumulative right output value 0 rn' (Step S1212: No), then the cumulative left output value I 0 1η" I is the cumulative right output value 0 r n at the sampling time n' 'T before the previous one. If it is not larger than "(Step S1213: No), it is determined that the left and right gain difference correction coefficients are in a divergent state, and the convergence-divergence state flag is set to 0 (Step S1214). Therefore, the correction amount α is set to 0.4% (step S1215).

[0201] Here, flags will be explained. The flags are F Θ r used for right gain difference correction and F θ 1 used for left gain difference correction, respectively. Based on the comparison between the cumulative right output value 0 rn and the cumulative left output value | 0 In | at sampling time nT, each case is divided into two cases, and the initial state is cleared to "0". Again, the flags represent the states described in paragraph numbers 0112 to 0115 of Example 1.

[0202] Returning to the explanation of the flowchart, in step S1212, if the cumulative left output value I θ ΐη' I is larger than the cumulative right output value θ πι' at the previous sampling time n'T (step S12 12 : Yes), , the previous time was in an overrun state, and the flag F 0 11 = 1 is set (step S121 8), and the negative amount α is set to 0.2% (step S 1219). Similarly, in step S1213, if the cumulative left output value I 0 In'' I is larger than the cumulative right output value 0 rn, at the sampling time n'' T of the previous two times (step S1213: Yes), then An overrun state occurs, and the flag F Θ 11 = 0 is set (step S1216), and the correction amount α is set to 0.1% (step S1217).

[0203] When the correction amount is set in step S1217 or step S1219, it is then determined whether at least one of the flag F Θ rl or the flag F Θ r2 is set to "1" (step S 1220). The processing in this step is based on the left output value, and it is determined whether or not the current right gain difference correction coefficient Grn is in a converged state in the previous or two previous processes based on the results of the right gain difference correction process. The above two flags set in the previous or two previous processes are referenced.

[0204] In step S1220, if at least one of the flag F Θ rl or the flag F Θ r2 is “1” (step S 1220 : Yes), it is determined that the left and right gain difference correction coefficient is in a converged state, The convergence/divergence state flag is set to 1 (step S1221), and the process moves to the update process of step S1222. If the flag F Θ rl and the flag F Θ r2 are both “0” (step S 12 20 : No), the process moves to the update process of step S 1222 without setting the flag in step S 1221 .

[0205] Next, in order to update the current left gain difference correction coefficient, the left gain difference correction coefficient Gin at sampling time nT is added by a from the previous left gain difference correction coefficient Gin− 1. value (step S1222), it is determined that this time is an underrun state (step S1223), and the series of processing ends.

[0206] Next, using the flowchart shown in Figure 24, in step S1210 (see Figure 22), determine if the GPS bearing Gbn at the current sampling time nT is smaller than the GPS bearing Gam at the sampling time mT! /, the processing in case (step S1210: No) will be explained. First, it is determined whether the GPS bearing Gbn at the current sampling time nT is greater than the GPS bearing Gam at the sampling time mT (step S1224). If the GPS bearing Gbn at the current sampling time nT is not larger than the GPS bearing Gam at the sampling time mT (step S1224: No), the series of processes ends. [0207] In step S1224, if the GPS bearing Gbn at the current sampling time nT is greater than the GPS bearing Gam at the sampling time mT!/ (Step S1224: Yes), the cumulative ring buffer is set at the current sampling time nT. It is determined whether the cumulative left output value I 0 1η I recorded in is greater than the cumulative right output value 0 rn (step S1225). If the cumulative left output value I 0 1η I is not larger than the cumulative right output value 0 m (step S1225: No), the series of processing ends.

[0208] In step S1225, if the cumulative left output value I 0 In | is larger than the cumulative right output value 0 rn at the current sampling time nT (step S1225: Yes), then the previous sampling time n'T Judging whether or not the cumulative left output value I 0 1η, I is smaller than the cumulative right output value 0 rn' (step S 1226), and the cumulative left output value I 0 1η" I at the sampling time n' 'T before the previous time. is smaller than the cumulative right output value 0 rn" (step S1227).

[0209] The cumulative left output value I 0 In' I at the previous sampling time n'T is not smaller than the cumulative right output value 0 rn (Step S1226: No), and the cumulative left output value at the sampling time n, 'T before the previous one is not smaller than the cumulative right output value 0 rn. If the value I 0 1η" I is not smaller than the cumulative right output value 0 m" (Step S12 27: No), it is determined that the left and right gain difference correction coefficients are in a divergent state, and the convergence-divergence state flag is set to 0. (Step S 1228). Therefore, the correction amount j8 is set to 0.4% (step S 1229).

[0210] In step S1226, the cumulative left output value I Θ In' at the previous sampling time n'T

If I is smaller than the cumulative right output value 0 rn' (Step S1226: Yes), the previous time is an underrun condition, the flag F Θ 12 = 1 is set (Step S 1232), and the correction amount j8 =0. 2%. is set (step S1233). Similarly, in step S1227, if the cumulative left output value I θ ΐη" I is smaller than the cumulative right output value 0 rn" at the sampling time n 'T of the time before the previous one (step S 1227 : Yes), the previous time is in an underrun state. Therefore, the flag F Θ 12 = 0 is set (step S1230), and the correction amount j8 is set to 0.1% (step S1231).

[0211] When the correction amount is set in step S1231 or step S1233, it is next determined whether at least one of the flag F Θ rl or the flag F Θ r2 is set to "1" ( step S1234). The processing in this step is shown in step S122 in Figure 23. As with 0, the left output value is used as the reference, and it is determined whether or not the current right gain difference correction coefficient Grn is in a converged state in the previous or two previous processes based on the results of right gain difference correction processing. The above two flags set in the previous or two previous processes are referenced.

[0212] In step S1234, if at least one of flag F Θ rl or flag F Θ r2 is “1” (step S 1234 : Yes), it is determined that the left and right gain difference correction coefficient is in a converged state. Then, the convergence/divergence state flag is set to 1 (step S1235), and the process moves to update processing in step S1236. If the flag F Θ rl and the flag F Θ r2 are both “0” (step S 1234 : No), the process moves to the update process of step S 1236 without setting the flag in step S 1235 .

[0213] Next, in order to update the current left gain difference correction coefficient, the left gain difference correction coefficient Gin at sampling time nT was subtracted by β from the previous left gain difference correction coefficient Gin−1. value (step S 1236), determines that this is an overrun state (step S 1237), and ends the series of processing.

[0214] Next, the flowchart shown in FIG. 25 will be explained. First, in step S1209 (see FIG. 22), when the sensor orientation Sam is detected at the sampling time mT, the processing will be explained when the right output value is lower than the reference value (step S1209: No). First, when sensor orientation Sam is detected at sampling time mT, it is determined whether the left output value is a reference force or not (step S1238). If the left output value exceeds the reference value (step S1238: No), the series of processing ends.

[0215] In step S1238, if the left output value is the reference (step S1238: Yes), next, determine whether the GPS bearing Gbn at the current sampling time nT is smaller than the GPS bearing Gam at the sampling time mT. (Step S 1239). If the GPS bearing Gbn at the current sampling time nT is not smaller than the GPS bearing Gam at the sampling time mT (step S1239: No), the process moves to step S1253 (see Figure 26).

[0216] In step S1239, if the GPS bearing Gbn at the current sampling time nT is smaller than the GPS bearing Gam at the sampling time mT (Step S1239: Yes), Then, it is determined whether the cumulative right output value 0 rn recorded in the ring buffer at the current sampling time nT is greater than the cumulative left output value I 0 1n | (since it is a negative output, it is compared as an absolute value). (Step S1240). In step S1240, if the cumulative right output value 0 rn is not larger than the cumulative left output value I 0 1η I (step S1240: No), the series of processes ends.

[0217] In step S1240, if the cumulative right output value Θ rn is larger than the cumulative left output value I 0 1η I at the current sampling time nT (step S1240: Yes), then at the previous sampling time n,T Judging whether the cumulative right output value 0 rn is smaller than the cumulative left output value I 0 ln, | (step S1241), and determining whether the cumulative right output value 0 rn is smaller than the cumulative left output value I 0 ln, | at the sampling time n,,T before the previous time. Determine whether it is smaller than the value I 0 1η" | (Step S 1242).

[0218] The cumulative right output value Θ rn' at the previous sampling time η'Τ is not smaller than the cumulative left output value | Θ In , I (Step S 1241: No), and the cumulative right output value at the sampling time n,,T before the previous If the output value 0 rn" is not smaller than the cumulative left output value I 0 1η" | (Step S12 42: No), it is determined that the left and right gain difference correction coefficients are in a divergent state, and the convergence-divergence state flag =0. Set (Step S 1243). Therefore, the correction amount α is set to 0.4% (step S 1244).

[0219] In step S1241, if the cumulative right output value Θ rn' is smaller than the cumulative left output value I θ ΐη' I at the previous sampling time η, Τ (step S1241: Yes), the previous one is in an under-run state. , the flag F Θ rl = l is set (step S1247), and the correction amount α =0.2% (step S1248). Similarly, in step S1242, if the cumulative right output value 0 rn" is smaller than the cumulative left output value I Θ In" | at the sampling time η 'Τ of the previous sampling time (step S 1242 : Yes), the sampling time η 'Τ of the previous sampling is in an underrun state. Therefore, the flag F 0 rl = 0 is set (step S1245), and the correction amount α is set to 0.1% (step S1246).

[0220] When the correction amount is set in step SI 246 or step SI 248, it is next determined whether at least one of flag F Θ 11 or flag F Θ 12 is set to “1” ( step S1249). The processing in this step is based on the right output value, and the current The left gain difference correction coefficient Gin determines whether or not the convergence state is reached, and refers to the above two flags set in the previous or two previous processes.

[0221] In step S1249, at least one of flag F Θ 11 or flag F Θ 12 is set to “

1" (Step S1249: Yes), it is determined that the left and right gain difference correction coefficients are in a converged state, the convergence-divergence state flag is set to 1 (Step S1250), and the update process in Step S1251 is performed. to move to. If the flag F Θ 11 and the flag F Θ 12 are both “0” (step S 124 9 : No), the process moves to the update process of step S 1251 without setting the flag in step S 1250 .

[0222] Next, in order to update the current right gain difference correction coefficient, the right gain difference correction coefficient Gm at sampling time nT is subtracted by a from the previous right gain difference correction coefficient Gm− 1. (Step S1251), determines that this time is an overrun state (Step S1252), and ends the series of processing.

[0223] Finally, using the flowchart shown in Figure 26, in step S1239 (see Figure 25), calculate the case where the GPS bearing Gbn at the current sampling time nT is not smaller than the GPS bearing Gam at the sampling time mT. (Step S1239: No) will be explained below. First, it is determined whether the GPS bearing Gbn at the current sampling time nT is greater than the GPS bearing Gam at the sampling time mT (step S1253). If the GPS bearing Gbn at the current sampling time nT is not larger than the GPS bearing Gam at the sampling time mT (step S1253: No), the series of processes ends.

[0224] In step S1253, if the GPS bearing Gbn at the current sampling time nT is larger than the GPS bearing Gam at the sampling time mT (Step S1253: Yes), the cumulative amount recorded in the ring buffer at the current sampling time nT is It is determined whether the right output value Θ rn is smaller than the cumulative left output value I 0 1η I (step S 1254). If the cumulative right output value 0 rn is not smaller than the cumulative left output value | 0 In | at the current sampling time nT (step S 1254 : No), the series of processes ends.

[0225] In step S1254, if the cumulative right output value Θ rn is smaller than the cumulative left output value I 0 1η I at the current sampling time nT (step S1254: Yes), then the previous sampling time n, T , the cumulative right output value 0 rn, is larger than the cumulative left output value I 0 ln, | (step S1255) and whether the cumulative right output value 0 rn" is larger than the cumulative left output value I 0 1η" | at the sampling time n''T before the previous time (step S1255). Pu S 1256).

[0226] The cumulative right output value Θ rn, at the previous sampling time η'Τ is not greater than the cumulative left output value | Θ In , I (Step S1255: No), and the cumulative right output value at the sampling time n,,T before the previous one. If the value 0 rn" is not larger than the cumulative left output value I 0 1η" | (Step S12 56: No), it is determined that the left and right gain difference correction coefficients are in a divergent state, and the convergence-divergence state flag is set to 0. (Step S 1257). Therefore, the correction amount j8 is set to 0.4% (step S 1258).

[0227] In step S1255, if the cumulative right output value Θ rn, is larger than the cumulative left output value I 0 1n, I at the previous sampling time n, T (step S1255: Yes), the previous one is in an overrun state. , the flag FΘ r2 = 1 is set (step S1261), and the correction amount j8 is set to 0.2% (step S1262). Similarly, in step S1256, if the cumulative right output value 0 m" is larger than the cumulative left output value I 0 1η" | at the sampling time n 'T of the previous sampling time (step S 1256 : Yes), the sampling time n 'T of the previous sampling is in an overrun state. Therefore, the flag F 0 r2 = 0 is set (step S1259), and the correction amount j8 is set to 0.1% (step S1260).

[0228] When the correction amount is set in step S1260 or step S1262, it is next determined whether at least one of flag F Θ 11 or flag F Θ 12 is set to "1" (step S1263 ). The processing in this step is based on the right output value, as in step S124 9 in Figure 25, and the current left gain difference correction coefficient Gin has converged in the previous or two previous processing as a result of the left gain difference correction processing. It judges whether or not it is in the current state, and refers to the above two flags that were set in the previous or two previous processes.

[0229] In step S1263, if at least one of flag F Θ 11 or flag F Θ 12 is "1" (step S1263: Yes), it is determined that the left and right gain difference correction coefficient is in a converged state, The convergence/divergence state flag is set to 1 (step S1264), and the process moves to the update process of step S1265. If flag F Θ 11 and flag F Θ 12 are both “0” (step S 126 3 : No), the update processing in step S 1265 is performed without setting the flag in step S 1264. Transition.

[0230] Next, in order to update the current right gain difference correction coefficient, the right gain difference correction coefficient Grn at sampling time nT is the value obtained by adding β from the previous right gain difference correction coefficient Grn−1. (Step S1265), determines that this time is an underrun state (Step S1266), and ends the series of processing.

[0231] Through the processing described above, by using either the currently updated left/right gain difference (sensitivity difference) correction coefficient Gin or Grn, the detection error of the angular velocity sensor is removed. Sensor orientation can be calculated. As defined earlier, the detection error referred to here is the detection error due to the gain difference (sensitivity difference) of the angular velocity sensor due to the difference in the turning direction of the vehicle. In the second embodiment, as in the first embodiment, the detection error is calculated with high precision, so the current overrun state or underrun state is accurately reflected in the setting of the correction coefficient. Therefore, error correction due to the left and right gain difference can be performed automatically and with high precision, and accurate sensor orientation and travel distance per unit time can be obtained, allowing accurate navigation of the vehicle.

[0232] Furthermore, as a more preferred example, Example 1 and Example 2 may be performed simultaneously. By performing the error correction according to the first embodiment and the second embodiment within the same navigation device 300, it is possible to more accurately navigate the vehicle.

[0233] Note that the direction calculation method described in this embodiment can be realized by executing a previously prepared program on a computer such as a personal computer or a workstation. This program is recorded on a computer-readable recording medium such as a hard disk, flexible disk, CD-ROM, MO, DVD, etc., and is executed by reading the recording medium by the computer. Furthermore, this program may be a transmission medium that can be distributed via a network such as the Internet.

Claims

The scope of the claims

[1] An azimuth calculation means that calculates a sensor azimuth using an output value of an angular velocity sensor and also calculates a GPS azimuth based on a GPS signal;

a recording means for recording the amount of change in the output value of the angular velocity sensor as a value larger (positive amount of change) and a value smaller (negative amount of change) than a predetermined reference value at each predetermined sampling period;

detection means for detecting two sampling times that satisfy a predetermined condition based on the sampling period in the recording means;

Comparison of the values of the sensor orientation calculated by the orientation calculation means at two sampling times detected by the detection means, or comparison of cumulative values of positive and negative changes recorded by the recording means. Comparison means for performing one or more of the following: a correction amount determining means for determining a correction amount for correcting the detection error of the sensor orientation based on the comparison result of the comparison means;

Correction azimuth calculation means for calculating a correction azimuth in which a detection error of the sensor azimuth calculated by the azimuth calculation means is corrected using the correction amount determined by the correction amount determination means;

An azimuth calculation device comprising:

[2] An azimuth calculation means that calculates the sensor azimuth using the output value of the angular velocity sensor and also calculates the GPS azimuth based on the GPS signal;

When a positive or negative amount of change is continuously recorded a predetermined number of sampling times by the recording means, the sampling time (first time) at which the recording started is detected, and the first time is detected. A value obtained by accumulating the amount of positive change recorded by the recording means from time (positive cumulative value) is compared with a value obtained by accumulating the amount of negative change (negative cumulative value), and the positive cumulative value is determined. Detect the sampling time (second time) when and the negative cumulative value become equal. detection means,

The value of the GPS direction detected by the detection means at the first time and the value of the GPS direction at the second time are compared, and the value of the sensor direction at the first time and the value of the sensor direction at the second time are compared. a comparison means for comparing the value of the sensor orientation at

Based on the comparison result by the comparison means, a correction amount for correcting the detection error of the sensor orientation is determined based on the direction corresponding to the amount of change continuously recorded by the recording means. A quantity determining means,

An azimuth calculation device comprising:

[3] When determining the correction amount, the correction amount determining means compares the results of comparing the sensor orientation values used in the previous correction amount determination and the sensor orientation values used in the previous correction amount determination. The azimuth calculation device according to claim 2, wherein the correction amount is adjusted based on the result so that the correction amount converges.

[4] An azimuth calculation means that calculates a sensor azimuth using the output value of the angular velocity sensor and also calculates a GPS azimuth based on a GPS signal;

When the recording means records a positive amount of change or a negative amount of change consecutively for a predetermined number of sampling times, the sampling time (first time) at which the recording was started is detected, and the direction is detected. In the calculation means, a detection means for detecting a sampling time (second time) at which a sensor orientation equal to the sensor orientation at the first time is calculated;

The value of the GPS direction detected by the detection means at the first time and the value of the GPS direction at the second time are compared, and the positive value between the first time and the second time is determined. The value that accumulates the amount of change (positive cumulative value) and the value that accumulates the amount of negative change (negative cumulative value) a comparison means for comparing the cumulative value of

An azimuth calculation device comprising:

[5] When determining the correction amount, the correction amount determining means calculates the positive cumulative value from the first time to the second time used for setting the previous correction amount and the negative cumulative value. Based on the comparison result with the cumulative value and the comparison result between the positive cumulative value and the negative cumulative value between the first time and the second time used for selecting the correction amount two times before, 5. The direction calculation device according to claim 4, wherein the correction amount is adjusted so that the correction amount converges.

[6] The azimuth calculation device according to any one of claims 1 to 5, wherein the recording means uses a ring buffer.

[7] An azimuth calculation step that calculates the sensor azimuth using the output value of the angular velocity sensor and also calculates the GPS azimuth based on the GPS signal;

a recording step of recording the amount of change in the output value of the angular velocity sensor as a value larger (positive amount of change) and a value smaller (negative amount of change) than a predetermined reference value at each predetermined sampling period;

a detection step of detecting two sampling times that satisfy a predetermined condition based on the sampling period in the recording step;

Either a comparison of the azimuth values calculated by the azimuth calculation means at the two sampling times detected by the detection step, or a comparison of cumulative values of positive and negative changes recorded by the recording step. A comparison process that performs the above,

a correction amount determining step of determining a correction amount for correcting the detection error of the sensor orientation based on the comparison result of the comparison means;

The direction calculation module uses the correction amount selected in the correction amount determination step. a correction direction calculation step of calculating a correction direction by correcting the detection error of the sensor direction calculated by the process;

A direction calculation method characterized by comprising:

[8] A direction calculation step of calculating the sensor direction using the output value of the angular velocity sensor and also calculating the GPS direction based on the GPS signal;

When a positive or negative amount of change is continuously recorded a predetermined sampling number of times in the recording process, the sampling time (first time) at which the recording started is detected, and the first time is detected. A value obtained by accumulating the amount of positive change recorded by the recording means from time (positive cumulative value) is compared with a value obtained by accumulating the amount of negative change (negative cumulative value), and the positive cumulative value is determined. a detection step of detecting a sampling time (second time) at which the negative cumulative value and the negative cumulative value become equal;

The value of the GPS direction at the first time detected by the detection step and the value of the GPS direction at the second time are compared, and the value of the sensor direction at the first time and the value of the sensor direction at the second time are compared. a comparison step of comparing the value of the sensor orientation at

Based on the comparison result in the comparison step, determining a correction amount for correcting the detection error of the sensor orientation with reference to the direction corresponding to the amount of change continuously recorded in the recording step. process and

a correction azimuth calculation step of calculating a correction azimuth in which the detection error of the sensor azimuth calculated in the azimuth calculation step is corrected using the correction amount selected in the correction amount determination step;

A direction calculation method characterized by comprising:

[9] A direction calculation step of calculating the sensor direction using the output value of the angular velocity sensor and also calculating the GPS direction based on the GPS signal;

The amount of change in the output value of the angular velocity sensor is recorded at each predetermined sampling period as a value larger (positive amount of change) and a value smaller (negative amount of change) than a predetermined reference value. a recording process to

When a positive amount of change or a negative amount of change is continuously recorded a predetermined number of sampling times in the recording step, the sampling time (first time) at which the recording was started is detected, and the direction is detected. a detection step of detecting, in the calculation means, a sampling time (second time) at which a sensor orientation equal to the sensor orientation at the first time is calculated;

The value of the GPS direction at the first time detected by the detection step is compared with the value of the GPS direction at the second time, and the positive value between the first time and the second time is compared. a comparison step of comparing the accumulated amount of change (positive accumulated value) with the accumulated value of negative changed amount (negative accumulated value);

a correction azimuth calculation step of calculating a correction azimuth in which a detection error of the sensor azimuth calculated in the azimuth calculation step is corrected using the correction amount determined in the correction amount determination step;

A direction calculation method characterized by comprising:

[10] An orientation calculation program that causes a computer to execute the orientation calculation method according to any one of claims 7 to 9.

[11] A recording medium on which the orientation calculation program according to claim 10 is recorded in a computer-readable manner.