JP2002341011A - Position measuring device, navigation system, position measuring method and navigation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position measuring device capable of calculating the present position more precisely, compared with in the past by the measured position by a satellite and an estimated position. SOLUTION: This device comprises a signal processing part 1 for detecting the receiving state of positioning information when measuring the present plane position and altitude of a vehicle on the basis of the past position information showing the plane position and altitude of the vehicle measured in the past by use of the positioning information transmitted from the GPS satellite, and a positioning calculation part 2 for generating the positioning altitude information showing the altitude of the vehicle by use of the positioning information, predicting the present altitude of the vehicle from the past position information, ignoring the past position information when the difference between the altitude shown by the positioning altitude information and the predicted altitude is a threshold or more, and the measuring the present plane position and altitude of the vehicle by use of the positioning information received at the present. At this time, the positioning calculation part 2 controls the threshold on the basis of the detected receiving state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a position measuring device and a navigation device, and a position measuring method and a navigation method, and more specifically, a so-called GPS (Global Positioning System) launched in space.
ing System) A position measuring device and a position measuring method for assisting movement while positioning the current position of a vehicle using positioning information transmitted from a satellite, and a navigation device and a position measuring method including the position measuring device. Belongs to the technical field of navigation methods including.

[0002]

2. Description of the Related Art In recent years, a current position of a moving object such as a vehicle (hereinafter referred to as a position) is used by using positioning information transmitted from a positioning satellite such as the above-mentioned GPS satellite used for specifying a position on the earth. In some cases, the position and altitude of the moving object are included.)

At this time, in the conventional position measurement processing using the positioning information, specifically, a prediction is performed based on a prediction method set in advance from the current position calculated by the previous position measurement processing. The current predicted position obtained,
The current current position is calculated using both the current positioning position calculated using only the currently received positioning information and the current positioning position. Then, the calculated current position is finally displayed as a current position calculated using the GPS satellites, for example, as a current position of the vehicle on a display in the vehicle.

On the other hand, in the above-described conventional position measurement processing, if the accuracy of the predicted position and the measured position at that time is deteriorated, the predicted position and the measured position calculated at an earlier timing are ignored. In addition, a reset process is performed in which the measured position obtained immediately after is used as the current position of the moving body at that time.

[0005] The decrease in the accuracy of the predicted position and the measured position, which indicates the timing at which the reset process is started, is specifically determined by the altitude information calculated as the measured position (that is, only the positioning information). The difference between the altitude information of the vehicle calculated based on the calculated position and the altitude information included in the predicted position (that is, the predicted altitude information calculated as the predicted position) is equal to or larger than a predetermined threshold value. At that time, it was determined that the accuracy of the predicted position was reduced. At this time, the threshold value was set to a somewhat high value corresponding to an error that would be included in the positioning information in principle.

[0006]

However, in the conventional position measurement processing having the above configuration, the threshold value is a fixed value and is set to a somewhat high value, so that the reset processing is not started when necessary. There was a problem that sometimes.

More specifically, for example, when the accuracy of the predicted position and the positioning position is reduced, the current position of the vehicle displayed on the display includes an apparent position error. However, since the reset processing based on the difference in the altitude information is not started, the position error may be further increased as a result.

Accordingly, the present invention has been made in view of the above-mentioned problems, and has as its object the problem that a position at which a current position can be calculated with higher accuracy than before using a measured position and a predicted position. It is an object of the present invention to provide a measuring device, a position measuring method, a navigation device including the position measuring device, and a navigation method including the position measuring method.

[0009]

In order to solve the above-mentioned problems, the invention described in claim 1 or 4 is directed to a mobile unit which has been measured in the past using positioning information transmitted from a positioning satellite. When measuring the current plane position and the altitude based on the past position information indicating the plane position and the altitude, the reception state of the positioning information is detected, and the altitude of the moving body is indicated using the positioning information. Generate positioning altitude information, predict the current altitude of the moving object from the past position information, when the difference between the altitude indicated by the positioning altitude information and the predicted altitude is equal to or greater than a threshold, the past The position information is ignored, and the current planar position and altitude of the moving object are measured using the positioning information currently received. At this time, the threshold is controlled based on the detected reception state.

Therefore, when the difference between the altitude indicated by the positioning altitude information and the predicted altitude is equal to or larger than the threshold, the current plane position and altitude are determined by using the positioning information currently received ignoring the past position information. When positioning is performed, the threshold value is controlled according to the reception state of the positioning information, so that the past position information is reflected in the position information including the current altitude according to the current reception state of the positioning information, that is, the reliability thereof. Can be controlled, and the current plane position and altitude can be measured more accurately.

[0011] In order to solve the above problem, the invention according to claim 2 or 5 is characterized in that, in the invention according to claim 1 or 4, whether or not the reception state is affected by multipath is determined. While detecting accuracy information indicating the accuracy of the positioning information itself that is included and transmitted in the positioning information, the accuracy indicated by the accuracy information is higher than a predetermined accuracy threshold, and the multipath Is not affected, control is performed to reduce the threshold.

Therefore, when the accuracy indicated by the accuracy information is high and the multipath is not affected, the threshold value is reduced. Therefore, when the accuracy of the positioning information is high, the period in which the past position information is used is shortened and the current positioning is performed. The current plane position and altitude are measured using the application information, and when the accuracy of the positioning information is high, the current plane position and altitude can be measured with higher accuracy.

According to a third aspect of the present invention, there is provided a position measuring device according to the first or second aspect of the present invention, which assists movement of the moving body based on the measured position. Auxiliary means such as a navigation processing unit.

According to a sixth aspect of the present invention, there is provided a position measuring method according to the fourth or fifth aspect of the present invention, which assists movement of the moving body based on the measured position. And an auxiliary step.

Therefore, according to the invention described in claim 4 or 8, the current plane position and altitude can be measured with higher accuracy in accordance with the state of reception of the positioning information to assist the movement of the vehicle. .

[0016]

Next, a preferred embodiment of the present invention will be described with reference to the drawings.

In the embodiment described below, a navigation device mounted on a vehicle as a moving body measures the current position of the vehicle using a GPS signal obtained by receiving the positioning information. This is an embodiment in which the present invention is applied to a navigation device that assists the movement of the vehicle.

(I) Embodiment of Position Measurement Processing First, before describing a specific embodiment, the above-described position measurement processing as a premise of the present invention will be described with reference to FIGS.
This will be described in detail with reference to FIG.

FIG. 1 is a schematic diagram showing the principle of the position measurement processing, and FIG. 2 is a flowchart showing specific processing in the position measurement processing. Here, the process shown by the flowchart shown in FIG. 2 is executed as a part of the navigation process executed as the whole navigation device of the embodiment.

As described above, the position measurement processing which is the premise of the present invention is based on the current predicted position obtained by predicting from the current position calculated by the previous position measurement processing based on a preset prediction method. The current position is calculated using both the current position and the current position calculated using only the positioning information currently received.

More specifically, using the positioning information transmitted from the GPS satellites in the previous time, the average value of the vehicle speed information obtained in the previous time and the average value of the vehicle speed information obtained in the current time are used. The moving distance calculated by multiplying the positioning interval (that is, the difference between the time at which the previous positioning information was received and the time at which the current positioning information was received) is used as the moving distance calculated at the previous positioning position (for example, reference numerals E1 to E6 in FIG. 1). A predicted position (for example, a predicted position R3 of predicted positions indicated by reference symbols R1 to R6 in FIG. 1) obtained by vector-wise addition to the measured position E2 of the indicated positioning positions.
And the positioning position currently calculated using the transmitted positioning information (for example, the positioning position E in FIG. 1).
3), based on the measured position E3 and the predicted position R
The position obtained by dividing the straight line connecting the line No. 3 and the gain (ratio) value which is a positive real number less than 1 which is empirically set in advance is obtained as a final current position (for example, a code shown in FIG. 1). The current position P among the current positions indicated by P1 to P6
3), and the positioning trajectory, which varies in principle at the positioning position E, is smoothed to calculate the current position P more accurately.

At this time, the current position P is schematically calculated by the following equation.

[0023]

## EQU1 ## Current position P = Gain value × Positioned position E + (1−Gain value) × Predicted position R Here, if the above gain value is close to “1”, the current position P is calculated from the measured position E. On the other hand, if it is closer to “0”, the current position P is calculated from the predicted position R. The gain value is empirically set in advance in consideration of various positioning conditions.

At this time, generally, the gain value is often close to “0”, so the position from the predicted position R is usually set as the current position P. If the accuracy is considered to be low, the reset processing is performed by setting the gain value to “1” in order to calculate the current position P without being affected by the past measured position E and the predicted position R. Do.

Here, a series of position measurement processing including the reset processing will be described in more detail. As shown in FIG. 2, in the position measurement processing, first, the positioning position E is received using the received positioning information. Is calculated (step S1), and then the predicted position R is calculated by the method described above (step S2).

Then, as described above, it is determined that the accuracy of the predicted position R has decreased, and a reset signal indicating whether or not to perform the reset process is generated by the method shown in FIG. 4 described later (step S3; YES) The above-described reset processing is executed by setting the gain value to "1" (step S5), and the measured position E obtained after the reset processing is set as the current position P (step S6), and the position corresponding to the current position P is determined. The displayed position is displayed on the display (step S7), and the process returns to the original navigation processing.

On the other hand, if it is determined in step S3 that the reset signal has not been generated (step S3; N
O) Assuming that the accuracy of the current predicted position R is good, the gain value is set so as to be used as it is in the calculation of the current position P (step S4), and the current position P is calculated by the processing of the above equation (step S6). The process proceeds to step S7.

(II) Embodiment of the Present Invention Next, an embodiment of the present invention based on the above-described series of position measurement processing will be described with reference to FIGS.

FIG. 3 is a block diagram showing the overall configuration of the navigation device according to the embodiment, and FIG. 4 is a flowchart showing a threshold setting process according to the embodiment.

As shown in FIG. 3, the navigation device S of the embodiment performs signal processing of a GPS signal SG from the GPS satellite received by a receiving unit (not shown).
Navigation data ND including accuracy information, which will be described later, which is set in advance.
A signal processing unit 1 as a detecting means for generating pseudo distance data GL indicating a pseudo distance from the navigation apparatus S to each GPS satellite; and the navigation data ND, the pseudo distance data GL, and multipath error information MP described later. A positioning calculation unit 2 as an altitude information generation unit, an altitude prediction unit, a measurement unit, and a control unit that perform the processing according to the embodiment (see FIG. 4) to generate the current position information NP indicating the current position P of the vehicle; A multipath detecting unit 3 that detects a so-called multipath based on the pseudo distance data GL corresponding to the GPS satellite, generates the multipath error information MP indicating a measurement error due to the multipath, and outputs the multipath error information MP to the positioning calculation unit 2 Calculates the so-called error ellipse based on the navigation data ND, and calculates the error ellipse information P indicating the position of the error ellipse and the corresponding area. And a navigation processing unit 5 as an auxiliary means for calculating the current position of the vehicle based on the current position information NP and the error ellipse information PH and performing necessary navigation processing using the calculated position. , Is constituted.

The signal processing unit 1 uses the GPS signals SG transmitted from a plurality of GPS satellites to generate the navigation data ND, and measures the distance error to each GPS satellite. A pseudo distance measuring unit 1b for generating the pseudo distance data GL.

Here, the multipath detecting section 3 determines whether or not each of the GPS signals SG is affected by multipath based on each of the inputted pseudo distance data GL. I have.

At this time, the multipath detection processing is performed by utilizing the fact that the pseudo distance changes to some extent continuously, and more specifically, when the previous current position P or the previous positioning is performed. A predicted value of the pseudo distance data GL of each GPS satellite is calculated from the pseudo distance data GL of each GPS satellite used in the above, and the predicted value and the pseudo distance data of each GPS satellite input at present are calculated. GL
Are compared with each other, and when it is determined that the difference is equal to or greater than a predetermined reference value, it is determined that multipath has occurred.

When it is determined that a multipath has occurred, the influence of the multipath is calculated as the multipath error information MP, and the calculated multipath error information MP is output to the positioning calculation unit 2.

At this time, after judging that the multipath has occurred, it is necessary to determine whether or not the influence has disappeared. It is determined that the influence of the multipath has disappeared when only the continuation has been performed.

Next, the processing in the positioning calculation section 2 according to the embodiment will be described with reference to FIG.

As described above, in the positioning calculation unit 2, the current position P of the vehicle is determined based on the navigation data ND, the pseudo distance data GL, and the multipath error information MP.
Is generated, the current position P is calculated by the position measurement processing shown in FIGS. 1 and 2 and the reset signal used in the position measurement method is generated. Figure 4 below
Is performed by the processing shown in FIG.

That is, as shown in FIG. 4, in the reset signal generation processing of the embodiment, first, the GPS signal SG
Whether the accuracy itself is high or what is currently called DGPS
(Differential Global Positioning System) It is determined whether the vehicle is moving by the positioning method (step S1).
0).

Here, whether or not the accuracy of the GPS signal SG itself is high is determined based on satellite accuracy information included in the navigation data ND itself.

On the other hand, the DGPS positioning method is a configuration in which positioning information from a GPS satellite is temporarily received by a reference station on the ground, and a corrected GPS signal in which a positioning error contained therein is corrected is transmitted to the vehicle again. Is a method of positioning the current position of the vehicle, and is determined by whether or not the modified GPS signal is received by a receiving unit (not shown),
When the result of the determination is input to the positioning calculation unit 2, the D
It is determined whether the GPS positioning method is currently used.

Then, in the determination of step S10,
When the accuracy of the GPS signal SG itself is low and the current position is not detected by the DGPS positioning method (step S
10; NO), the process proceeds to step S14 without changing the threshold value while keeping the currently set value (step S12).

On the other hand, in the judgment of step S11, GP
If the accuracy of the S signal SG itself is high or the current position is detected by the DGPS positioning method (step S1
0; YES) Next, whether or not a multipath is currently occurring is confirmed based on the multipath error information MP (step S11).

When it is determined that the accuracy of the positioning position E indicated by the GPS signal SG is reduced due to the influence of the multipath (step S1).
1; YES) Proceed to the step S12, on the other hand, if no multipath has occurred (step S11; N)
O) Next, the threshold is reduced to calculate the current position P using the positioning position E, which is estimated to have higher accuracy as the position (step S13), and the next step S14
Move to.

When the threshold is set by the above-described series of processing (steps S12 and S13), the altitude indicated by the altitude information as the positioning position E calculated based on the positioning information and the altitude are calculated. It is determined whether or not the difference between the altitude indicated by the altitude information calculated as the position R is equal to or greater than the set threshold (step S14). S14; YES), a process of generating the reset signal and setting the measured position E as the current position P is performed (step S15; see steps S3 and S5 in FIG. 2), and returns to the original navigation process.

On the other hand, if it is determined in step S14 that the difference between the altitudes is smaller than the threshold (step S14; NO), it is determined that there is no need to perform the reset process, and the process directly proceeds to the original navigation process.

As described above, according to the processing in the positioning calculation unit 2 of the embodiment, the difference between the altitude indicated by the altitude information as the positioning position E and the altitude indicated by the altitude information as the predicted position R is set. When the current plane position and altitude are measured using the positioning information currently received ignoring the past positioning position E and the predicted position R when the threshold value is equal to or more than the threshold value, the threshold value is determined based on the positioning information. Since the control is performed in accordance with the reception state, it is controlled whether or not the past measured position E and the predicted position R are reflected in the position information including the current altitude according to the current state of reception of the positioning information, that is, the reliability thereof. It is possible to more accurately measure the current plane position and altitude to assist the movement of the vehicle.

When the accuracy of the positioning position E is high and the multipath is not affected, the threshold value is reduced.
And the period of using the predicted position R is shortened, and the current plane position and altitude are measured using the current positioning information. If the accuracy of the positioning information is high, the current plane position and altitude are more accurately calculated. Positioning can be performed.

In the above-described embodiment, the case where the present invention is applied to the detection of the current position P when the vehicle is moving has been described.
The present invention can be widely applied to the case where the current position P of a moving object (including a person having the portable navigation device S) is detected using the positioning information from the PS satellite.

In the above-described embodiment, the reset process is always executed when the reset signal is generated. In addition, the reset process is always executed when the reset signal is generated. Instead, the generation of the reset signal may be considered as one of the determination factors, and it may be configured to determine whether to actually perform the reset process in consideration of other factors.

Further, a program corresponding to the flowcharts shown in FIGS. 2 and 4 is stored in, for example, a flexible disk, a hard disk, a semiconductor memory, or the like, and read and executed by a general-purpose microcomputer. The microcomputer or the like may be configured to function as the positioning calculation unit 2 according to the embodiment.

[0051]

As described above, according to the first or fourth aspect of the present invention, when the difference between the altitude indicated by the positioning altitude information and the predicted altitude is equal to or larger than the threshold, the past position information is obtained. In the case of ignoring the current plane position and altitude using the currently received positioning information, the threshold is controlled in accordance with the reception state of the positioning information. It is possible to control whether or not to reflect the past position information on the position information including the current altitude according to the reliability, and it is possible to more accurately measure the current plane position and altitude.

According to the invention described in claim 2 or 5, in addition to the effect of the invention described in claim 1 or 4, when the accuracy indicated by the accuracy information is high and there is no influence of multipath. Since the threshold value is reduced, when the accuracy of the positioning information is high, the period in which the past position information is used is shortened, and the positioning of the current plane position and the altitude is performed using the current positioning information, and the accuracy of the positioning information is reduced. In a high case, the current plane position and altitude can be measured with higher accuracy.

According to the third or sixth aspect of the present invention, it is possible to more accurately measure the current plane position and altitude in accordance with the state of reception of the positioning information to assist the movement of the vehicle.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a principle of a position measurement process which is a premise of an embodiment.

FIG. 2 is a flowchart illustrating processing of a position measurement processing which is a premise of the embodiment.

FIG. 3 is a block diagram illustrating an overall configuration of the navigation device according to the embodiment.

FIG. 4 is a flowchart illustrating a threshold setting process according to the embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Signal processing part 1a ... Data decoding part 1b ... Pseudo distance measuring part 2 ... Positioning calculating part 3 ... Multipath detecting part 4 ... Error ellipse calculating part 5 ... Navigation processing part S ... Navigation device SG ... GPS signal ND ... Navigation data GL: pseudo distance data MP: multipath error information NP: current position information PH: error ellipse information

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F029 AA02 AB07 AB13 AC03 AC09 AC16 AD00 5H180 AA01 CC12 FF05 FF07 FF22 FF32 5J062 AA03 BB01 CC07 DD12 DD24 DD25 EE01 EE04

Claims (6)

[Claims] 1. Position measurement for measuring the current plane position and altitude based on past position information indicating the plane position and altitude of a moving object measured in the past using positioning information transmitted from a positioning satellite. In the apparatus, a detecting means for detecting a reception state of the positioning information, a positioning altitude information generating means for generating positioning altitude information indicating an altitude of the moving object using the positioning information, and Altitude estimating means for estimating the current altitude of the moving object, and when the difference between the altitude indicated by the positioning altitude information and the predicted altitude is equal to or greater than a threshold value, ignoring the past position information, and Measuring means for measuring the current plane position and altitude of the moving object using the positioning information, and controlling the threshold based on the detected reception state. And a control means. 2. The position measurement device according to claim 1, wherein the detection unit determines whether or not the reception state is affected by multipath and is included in the positioning information and transmitted. While detecting accuracy information indicating the accuracy of the positioning information itself, the control unit, when the accuracy indicated by the accuracy information is higher than a preset accuracy threshold, and is not affected by the multipath, A position measuring device, wherein the position is controlled so as to reduce the threshold value. 3. A navigation device, comprising: the position measuring device according to claim 1; and an auxiliary unit that assists movement of the moving object based on the measured position. 4. Position measurement for measuring the current plane position and altitude based on past position information indicating the plane position and altitude of a mobile object measured in the past using positioning information transmitted from a positioning satellite. In the method, a detection step of detecting a reception state of the positioning information, a positioning altitude information generating step of generating positioning altitude information indicating an altitude of the moving object using the positioning information, An altitude prediction step of estimating the current altitude of the moving object, and when a difference between the altitude indicated by the positioning altitude information and the predicted altitude is equal to or greater than a threshold, the past position information is ignored and the currently received A measuring step of measuring the current plane position and altitude of the moving object using the positioning information, and controlling the threshold value based on the detected reception state. And a control step. 5. The position measuring method according to claim 4, wherein, in the detecting step, whether or not multipath is affected by the multipath and the positioning information are transmitted as the reception state. While detecting accuracy information indicating the accuracy of the positioning information itself, in the control step, the accuracy indicated by the accuracy information is higher than a predetermined accuracy threshold value and is not affected by the multipath. And performing control to reduce the threshold value. 6. A navigation method, comprising: the position measurement method according to claim 4 or 5; and an assisting step of assisting movement of the moving object based on the located position.