JP2008175716A - Navigation system for specifying one's own vehicle position based on altitude variation, and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To acquire accurate information on altitude variation, to specify the road on which one's own vehicle travels based on the acquired information on altitude variation, and to correctly display the one's own vehicle position. <P>SOLUTION: This navigation system detects atmospheric pressure using a pressure sensor, and detects variation in voltage by comparing the output voltage from the pressure sensor with a predetermined reference voltage. The navigation system determines gradient based on the variation in voltage and altitude variation, compares it with the gradient of the road in map data of the point having a one's own vehicle candidate, and corrects the reliability of the one's own vehicle candidate having matching gradient. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a navigation device mounted on a vehicle or the like.

  A normal in-vehicle navigation system has a function to specify the position where the vehicle travels using GPS (Global Positioning System), wheel speed sensor, gyro sensor, etc. after traveling near the junction of expressway or elevated road Is provided. When the position where the vehicle travels is obtained using only GPS, if the GPS data reception frequency is low, the current position cannot be grasped in the reception gap. To compensate for this, the virtual current position is calculated using a wheel speed sensor and a gyro sensor (dead reckoning technology), and the calculated virtual current position and map data are subjected to matching processing (map matching technology) to identify the vehicle position. In this way, the vehicle position is specified. However, there may be an error between the coordinates using GPS and the map data that the navigation device actually has. The difference in coordinates between the expressway and elevated road as described above and other parallel roads May not be accurately displayed on the screen.

  For this reason, Patent Document 1 discloses a vehicle position specifying method capable of displaying a highly reliable vehicle position using highly accurate altitude information and a device according to the method.

  That is, Patent Document 1 discloses the absolute location of a specific location using DSRC (Dedicated Short Range Communication), which is communication used in an ETC system (Electronic Toll Collection System). An invention is described in which a high altitude is received and a relative altitude change calculated by autonomous navigation using a gyro or the like is used as a correction altitude for the received altitude.

JP 2006-275619 A

  However, with the above technology, DSRC communication such as an ETC device can be performed, and as long as the absolute altitude can be obtained frequently (that is, when traveling in a place where such infrastructure is established) The absolute altitude can be acquired frequently, but if the communication is not received frequently, an error related to the altitude will occur in proportion to the length of the interval until the next DSRC communication is performed. .

  An object of the present invention is a technology capable of acquiring highly accurate altitude change information, identifying a road on which the vehicle is traveling based on the acquired altitude information, and accurately displaying the position of the vehicle. Is to provide.

  In order to solve the above problems, the navigation device of the present invention uses an atmospheric pressure sensor every time it travels a point where it is necessary to determine the altitude in order to identify the position of the host vehicle, such as when traveling near an elevated road. And a means for measuring minute changes in atmospheric pressure and detecting the degree of ascent / descent of the road on which the vehicle is traveling.

  Further, using the detected degree of ascending / descending, it is determined whether or not the vehicle is traveling along an elevated road or a road parallel to a three-dimensional intersection, and each reliability of the calculated vehicle position candidates is corrected, Means for identifying the vehicle position are provided.

For example, the navigation device of the present invention is a navigation device mounted on a vehicle,
A position detection device for detecting a current position of the vehicle;
An altitude detecting device for detecting the altitude of the vehicle;
A display device mounted in the vehicle and displaying a current location using a map;
Elevation detection means for determining elevating of the road running from the amount of change in altitude detected by the altitude detection device,
Current position determining means for obtaining a current position on the road that most matches the lifting information determined by the lifting detection means;
Current position display means for displaying the current position specified by the current position determination means on the display device;
It is characterized by providing.

In addition, a navigation device mounted on a vehicle according to another embodiment of the present invention,
A position detection device for detecting a current position of the vehicle;
A display device mounted in the vehicle and displaying a current location using a map;
An atmospheric pressure sensor,
Voltage difference acquisition means for detecting a difference between a voltage obtained as a result of measurement by the atmospheric pressure sensor and a predetermined reference voltage;
Elevation detection means for determining elevating of the road running from the amount of change in altitude detected by the voltage difference acquisition means,
Current position determining means for obtaining a current position on the road that most matches the lifting information determined by the lifting detection means;
Current position display means for displaying the current position specified by the current position determination means on the display device;
It is characterized by providing.

Furthermore, in the present location display method of the navigation device mounted on the vehicle,
The navigation device
A position detection device for detecting a current position of the vehicle;
An altitude detecting device for detecting the altitude of the vehicle;
A display device mounted in the vehicle and displaying a current location using a map;
With
Elevation detection step for determining elevating of the road running from the amount of change in altitude detected by the altitude detection device,
A current position determination step for obtaining a current position on a road that most matches the lift information determined in the lift detection step;
A current position display step of displaying the current position specified by the current position determination means on the display device;
It is characterized by performing.

  Below, the 1st Embodiment of this invention is described with reference to FIGS.

  FIG. 1 is a schematic configuration diagram of an in-vehicle navigation device 100 to which the first embodiment of the present invention is applied. As shown in the figure, the in-vehicle navigation device 100 includes an arithmetic processing unit 1, a display 2, a storage device 3, a voice input / output device 4, an input device 5, a wheel speed sensor 6, a gyro sensor 7, A GPS (Global Positioning System) receiving device 8, an ETC communication device 9, a beacon receiving device 10, and an atmospheric pressure sensor 11 are provided.

  The arithmetic processing unit 1 is a central unit that performs various processes. For example, the current location is detected based on information output from the various sensors 6, 7, 11 and the GPS receiver 8. Further, map data necessary for display is read out from the storage device 3 based on the obtained current location information. Further, the read map data is developed in graphics, and a mark indicating the current location is superimposed on the map data and displayed on the display 2. In addition, the map data stored in the storage device 3 is used to search for an optimum route (recommended route) that connects the starting point (current location) instructed by the user and the destination. Further, the user is guided using the voice input / output device 4 and the display 2.

  The display 2 is a unit that displays graphics information generated by the arithmetic processing unit 1. The display 2 is composed of a CRT, a liquid crystal display, or the like.

  The storage device 3 includes a storage medium such as a CD-ROM, DVD-ROM, HDD (hard disk device), or IC card. This storage medium stores map data (not shown) and measurement point data 330 described later. The map data is map data used in a normal navigation device, and has link information representing road start point, end point, and gradient information.

  The voice input / output device 4 converts the message to the user generated by the arithmetic processing unit 1 into a voice signal and outputs it. Also, a process of recognizing the voice uttered by the user and transferring the contents to the arithmetic processing unit 1 is performed.

  The input device 5 is a unit that receives instructions from the user. The input device 5 includes hardware switches such as a scroll key and a scale change key, a joystick, and the like.

  The wheel speed sensor 6, the gyro sensor 7, and the GPS receiver 8 are used for detecting the vehicle position by the in-vehicle navigation device 100. The wheel speed sensor 6 measures the travel distance from the product of the wheel circumference and the measured number of rotations of the wheel, and further measures the angle at which the moving body is bent from the difference in the number of rotations of the paired wheels. The gyro sensor 7 is constituted by an optical fiber gyro, a vibration gyro, or the like, and detects an angle at which the moving body rotates. The GPS receiver 8 receives a signal from a GPS satellite and measures the distance between the moving body and the GPS satellite and the rate of change of the distance with respect to three or more satellites, thereby moving the current position, traveling speed, and traveling of the moving body. Measure orientation.

  The ETC communication device 9 is an in-vehicle device of an ETC system. When passing through the ETC gate, billing information and other altitude information are transmitted and received.

  The beacon receiving device 10 receives current traffic information, regulation information, SA / PA information, parking lot information, and the like sent from the beacon.

  The atmospheric pressure sensor 11 is an apparatus that measures the atmospheric pressure around the vehicle with an absolute atmospheric pressure sensor or the like and outputs a measurement result (a voltage of 0 V or more and 5 V or less in the present invention, depending on product specifications) as a voltage. is there.

  In general, it is known that the atmospheric pressure changes according to a change in altitude, and the amount of change has a certain relationship. Therefore, in the present invention, the output voltage from the atmospheric pressure sensor is acquired as means for detecting a change in altitude, and the change in altitude is detected from the change in voltage.

  FIG. 2 is a functional block diagram of functions related to the present invention of the arithmetic processing unit 1.

  As shown in the figure, the arithmetic processing unit 1 includes a main control unit 101, an elevation detection unit 102, a virtual current location calculation unit 103, a current position determination unit 104, and a display processing unit 105.

  The up / down detection unit 102 detects the output voltage from the atmospheric pressure sensor 11 and compares it with a predetermined reference voltage to detect the up / down of the own vehicle, and corrects the reliability of the vehicle position candidate described later. It is a functional part to do. Normally, the atmospheric pressure increases as the altitude decreases, and conversely, the atmospheric pressure decreases as the altitude increases. Utilizing this fact, the lift detection unit 102 determines whether the host vehicle is lifted or lowered.

  The virtual current location calculation unit 103 is a functional unit that is also installed in an existing navigation system, and calculates a plurality of virtual current locations by performing position correction on a plurality of current location candidates. For the correction, the travel distance calculated from the travel speed of the own vehicle acquired from the wheel speed sensor 6 and the circumference of the wheel, the travel angle acquired from the gyro sensor 7, and the coordinates of the current position received by the GPS receiver 8 Is used.

  The current position determination unit 104 calculates a plurality of vehicle position candidates and their reliability by matching a plurality of calculated virtual current locations with the terrain information of the map data stored in the storage device 3 (map matching). This is a functional unit that extracts a position candidate having the highest reliability as a display candidate.

  The display processing unit 105 is a functional unit that displays the display candidates extracted by the current position determination unit 104 on the display 2. Receive map data and display candidates in the area that is required to be displayed on the display 2, and use the specified scale and drawing method to create roads, other map components, current location, destination, and arrows for recommended routes. A map drawing command is generated so as to draw the mark. Then, the generated command is transmitted to the display 2.

  FIG. 3 is a diagram illustrating a hardware configuration example of the arithmetic processing unit 1.

  As illustrated, the arithmetic processing unit 1 has a configuration in which devices are connected by a bus 33. The arithmetic processing unit 1 includes a CPU (Central Processing Unit) 21 that executes various processes such as numerical calculation and control of each device, and a RAM (Random Access Memory) that stores map data, arithmetic data, and the like read from the storage device 3. ) 22, a ROM (Read Only Memory) 23 for storing programs and data, a DMA (Direct Memory Access) 24 for transferring data between the memories and between the memory and each device, and graphics drawing. In addition, a drawing controller 25 that performs display control, a video random access memory (VRAM) 26 that stores graphics image data, a color palette 27 that converts image data into RGB signals, and an A / D that converts analog signals into digital signals. Converter 28 and an SCI (Serial Communication Interface) that converts the serial signal into a parallel signal synchronized with the bus. ace) 29, a PIO (Parallel Input / Output) 30 that puts a parallel signal on the bus in synchronization with the bus, a counter 31 that integrates a pulse signal, and a D / A converter that converts a digital signal into an analog signal 32.

  Each component and function described above is achieved by the CPU 21 executing a program loaded into the RAM 22 or ROM 23.

  FIG. 4 is a circuit diagram specifically illustrating a connection circuit between the atmospheric pressure sensor 11 and the CPU 21. The atmospheric pressure sensor 11 is connected to a capacitor 402, and the capacitor 402 is connected to the non-inverting input terminal of the differential amplifier 401. The differential amplifier 401 is connected to the CPU 21 through the A / D converter 28, and a predetermined reference voltage is applied to a negative terminal that is not connected to the capacitor 402 among the terminals of the differential amplifier 401.

  The atmospheric pressure is detected by the atmospheric pressure sensor 11, and the detected atmospheric pressure is output as a voltage of 0V to 5V.

  The output voltage is input as an input value to the non-inverting input terminal of the differential amplifier 401 via the capacitor 402. At this time, since the direct current component of the current input to the differential amplifier 401 is cut by passing through the capacitor 402, only the alternating current component can flow into the differential amplifier 401.

  The difference between the voltage flowing into the differential amplifier 401 and the reference voltage flowing from the inverting input terminal is amplified and transferred to the CPU 21. Since the differential voltage is amplified by the differential amplifier 401, the CPU 21 can acquire the voltage change of the atmospheric pressure sensor with high accuracy. Thereby, the elevation detection unit 102 which is a functional unit of the CPU 21 determines that the atmospheric pressure has increased when the acquired voltage has increased, that is, the altitude has decreased relatively, and when the acquired voltage has decreased. It can be determined that the atmospheric pressure has decreased, that is, the altitude has increased relatively.

  FIG. 5 is a diagram illustrating a configuration of the measurement point data 330. The measurement point data 330 is a measurement that stores a link ID indicating a road to be continuously measured for each link identification code (link ID 331) indicated by a line segment connecting the start point and the end point after dividing the road according to a specific rule. Continuation link ID 332 is included.

  The measurement continuation link ID 332 sets, for each link ID 331, a link ID of a road that continues to be detected by the same atmospheric pressure sensor among roads in contact with the link. For example, if the vehicle is scheduled to travel on a certain link and there is a link that continues to use the reference value, the link ID is stored in the measurement continuation link ID 332. As a result, it is possible to continue without worrying about link breaks even in parallel running sections of elevated roads and general roads that span multiple links, as well as complex three-dimensional intersections where elevators of multiple elevated roads intersect. Up and down can be detected.

  [Description of Operation] Next, the operation of the in-vehicle navigation device 100 having the above-described configuration will be described.

  FIG. 6 is a flowchart showing the flow of the vehicle position calculation process.

  The own vehicle position calculation process is a process that is started when the in-vehicle navigation device 100 operates and is repeatedly executed at predetermined intervals until the in-vehicle navigation device 100 stops operating.

  The virtual current location calculation unit 103 uses the GPS sensor 8, the wheel speed sensor 6, and the gyro sensor 7 to acquire coordinates, a movement distance, and a movement direction. Specifically, the travel distance is calculated from the travel speed of the host vehicle acquired from the wheel speed sensor 6 and the circumference of the wheel, and the travel angle acquired from the gyro sensor 7 and the coordinates of the current position received by the GPS receiver 8 are obtained. Obtain (S011).

  Next, the virtual current location calculation unit 103 adds the acquired travel distance, travel angle, and coordinates of the current position as correction values to a plurality of current position candidates, and calculates a virtual position that is a temporary position of the current position. A plurality of current locations are calculated (S012).

  Next, the current position determination unit 104 matches the position on the map that approximates each of the virtual current positions calculated by the virtual current position calculation unit 103 with the terrain information, and calculates a vehicle position candidate.

  At this time, the current position determination unit 104 calculates and stores the reliability (for example, 0 to 100, the higher the numerical value, the higher the reliability) for each of a plurality of vehicle position candidates obtained as a result of the map matching. The data is stored in the device 3 (S013).

  Next, the current position determination unit 104 extracts a candidate having the highest reliability from the vehicle position candidates as a display candidate (S014).

  Specifically, for example, when there are seven virtual current locations, the current position determination unit 104 draws a perpendicular to the link at the closest distance from each of the seven points, and automatically sets the intersection of the perpendicular and the link. Car position candidate. There are seven vehicle position candidates obtained in this way. Here, the current position determination unit 104 has the shortest distance between the virtual current position and the vehicle position candidate among the vehicle position candidates existing on public roads that have many points that match the shape and coordinates of the trajectory that has traveled in the past. The reliability of the vehicle position candidate with the least deviation in the left-right direction in which the road and the vehicle travel is set to the highest (for example, 100). Further, for example, the reliability of the vehicle position candidate having the maximum distance between the virtual current location and the vehicle position candidate and having a large shift in the left and right directions in which the road and the vehicle travel is set low (for example, 1). If the reliability is already set, the current position determination unit 104 calculates a correction value so as to correct the reliability according to a certain condition.

  Subsequently, the display processing unit 105 finely corrects the coordinates of the display candidates and displays them on the display 2 (S015). Specifically, the vehicle position is synthesized according to the viewpoint of the screen on which the display candidates are displayed, and displayed according to the terrain data on the map.

  The above is the flow of the vehicle position calculation process that is repeatedly executed at predetermined intervals.

  Next, the flow of the elevated vehicle position calculation process that is performed in parallel with the own vehicle position calculation process that is repeatedly executed at predetermined intervals and that is executed while traveling at a specific point will be described with reference to FIG. explain.

  When traveling on the road specified by the link ID 331 of the measurement point data 330 stored in the storage device 3, first, the elevation detection unit 102 of the CPU 21 acquires the output voltage from the atmospheric pressure sensor 11 (S111). . For example, although it depends on the specifications of the atmospheric pressure sensor, a specific voltage value such as 4.76 V is acquired.

  Next, the raising / lowering detection part 102 raises / lowers the own vehicle based on the change amount of the difference value (for example, 0.01V) between a predetermined reference voltage (for example, 4.75V) and the voltage obtained from the atmospheric pressure sensor 11. Is determined (S112).

  The elevation detection unit 102 calculates an amount by which the acquired voltage difference value has changed from the previously acquired voltage difference value. If the calculated change is a positive increment (that is, if the difference from the reference voltage is larger in the positive direction than at the previous measurement), it indicates that the altitude has decreased. The detection unit 102 specifies that the vehicle has traveled on the road where the vehicle descends.

  Similarly, if the calculated change is a negative increment (that is, if the difference from the reference voltage is larger in the negative direction than at the previous measurement), to indicate that the altitude has increased The elevating detection unit 102 specifies that the vehicle has traveled on the ascending road.

  Of course, when the calculated change amount is 0 (that is, when the difference from the reference quasi-voltage does not change from the previous measurement), the elevation detection unit 102 indicates that the altitude is constant. Identifies that the vehicle traveled on a flat road.

  Note that, actually, the voltage difference value is amplified by the hardware function of the capacitor 402 and the differential amplifier 401 shown in FIG. 4, so the CPU 21 may acquire a minute difference value of the amplified voltage. it can. That is, even if the difference value is a minute voltage, the difference value can be accurately captured.

  Next, based on the elevation of the host vehicle identified in S112, the elevation detection unit 102 calculates the link data of the road on which each of the vehicle location candidates calculated in Step S013 and the undulations in the movement direction of the vehicle location candidates. Are extracted, and the vehicle position candidate that matches the movement of the vehicle is extracted. Then, the reliability of the extracted vehicle position candidate is corrected according to a predetermined standard (S113).

  Specifically, only the own vehicle position candidates B, C, and D are in the traveling direction among the roads where the own vehicle position candidates A to G exist in the “down” state. When the road is “down”, the reliability of the vehicle position candidates B, C, and D is set to a predetermined constant k (0 <k ≦ 1, for example, k = 0.7, for example, as shown in the equation). ) Is added to a value to be added such as 100 × (1−k) (for example, 30), etc., and corrected.

Reliability = (Reliability before correction) × k + 100 × (1−k) (0 <k ≦ 1) Formula For example, the reliability of the vehicle position candidates B, C, and D is 80, 50, and 40, respectively. When k = 0.7, the reliability after correction is 86 (+6 increase), 65 (+15 increase), and 58 (+18 increase).

  And the raising / lowering detection part 102 determines whether the display candidate of the own vehicle (those with the highest reliability among the own vehicle position candidates) is traveling on the road designated by the measurement continuation link ID 332 (S114). ). That is, the elevation detection unit 102 determines whether a display candidate point has been obtained on the road specified by the measurement continuation link ID 332.

  As a result of the determination, after the display candidate of the own vehicle is obtained on the road specified by the link ID 331, the current display candidate of the own vehicle is obtained on the road specified by the measurement continuation link ID 332, The above steps S111 to S113 are repeatedly executed at predetermined intervals. When the own vehicle position exists on a road other than the road specified by the measurement continuation link ID 332, the elevation detection unit 102 ends the elevated own vehicle position calculation process.

  Based on the altitude, the elevated vehicle position calculation process is based on altitude with respect to the reliability that is the criterion for identifying the vehicle position candidate that is executed in step S014 of the vehicle position calculation process shown in FIG. Will be added. This makes it possible to calculate the position of the vehicle with higher accuracy and higher altitude.

  The configuration and operation of the first embodiment of the present invention have been described above.

The first embodiment of the present invention described above can acquire highly accurate altitude change information, identify the road on which the vehicle is traveling based on the acquired altitude change information, and determine the vehicle position. Next, a second embodiment of the present invention will be described with reference to FIGS.

  The second embodiment has basically the same configuration as the first embodiment.

  However, since there is a difference in the configuration of the connection between the atmospheric pressure sensor 11 and the CPU 21 shown in FIG. 4 of the first embodiment and the reference voltage setting process, the difference will be mainly described.

  FIG. 8 is a diagram illustrating a connection configuration between the atmospheric pressure sensor 11 and the CPU 21 according to the second embodiment.

  The atmospheric pressure sensor 11 is connected to a differential amplifier 401, and the differential amplifier 401 is connected to the CPU 21 via the A / D converter 28. The CPU 21 is connected to the inverting input terminal of the differential amplifier 401 through the D / A converter 32. Further, the storage device 3 is connected to the CPU 21. A reference voltage (variable) that the CPU 21 instructs to output is applied to the inverting input terminal of the differential amplifier 401.

  With this configuration, the CPU 21 can accurately amplify a minute difference between the voltage output from the atmospheric pressure sensor 11 and the reference voltage (variable) applied to the inverting input terminal of the differential amplifier 401. Can do.

  FIG. 9 is a diagram illustrating a configuration of the measurement point data 440 in the second embodiment. The measurement point data 440 has basically the same configuration as the measurement point data 330 in the first embodiment, but for each link ID 441, a reference measurement point link that is a place where the reference value of the output of the atmospheric pressure sensor is measured. The difference is that an ID442 column is added.

  When the own vehicle starts traveling on the road indicated by the reference measurement point link ID 442, the elevation detection unit 102 measures the current atmospheric pressure as a reference voltage (variable) to be applied to the inverting input terminal of the differential amplifier 401. Get the output voltage when

  Next, the operation of the elevated vehicle position calculation process in the second embodiment will be described with reference to FIG.

  FIG. 10 shows steps S211 to S215, but the point different from the first embodiment is that S211 that is an initialization process is added.

  In S211, the elevation detection unit 102 acquires a voltage to be used as a reference from the atmospheric pressure sensor 11, and stores it in the storage device 3 as a reference voltage.

  In the subsequent steps, the CPU 21 performs control so that the reference voltage to be used is the voltage stored in the storage device 3.

  In the second embodiment, the reference voltage (variable) is given by the CPU 21 based on the ambient atmospheric pressure.

  As a result, the altitude can be measured in a wider altitude range than in the first embodiment.

  Specifically, for example, in the vicinity of an altitude of less than 100 meters above sea level, there is generally an atmospheric pressure of about 850 hPa to 1150 hPa (approximately 900 to 1100 hPa excluding exceptional low pressure and high pressure). Although the absolute pressure sensor of the atmospheric pressure sensor depends on the product specifications, there are many sensors having a measurement range of about 150 hPa to 1150 hPa. Since the voltage output from the atmospheric pressure sensor has a width corresponding to the measurement range of the atmospheric pressure, an effective voltage is normally a narrow width of about 4.5 to 5V.

  On the other hand, at high altitudes, the atmospheric pressure decreases as the altitude increases. For example, in the vicinity of an altitude of 2000 meters, the atmospheric pressure is about 800 hPa, and the effective voltage is normally used in a narrow width around 3.5V.

In the first embodiment, a difference (for example, about 0 to 0.25 V) between the output voltage from the atmospheric pressure sensor 11 and the reference voltage (for example, 4.75 V) is obtained using the differential amplifier 401, and this is obtained. The amplified detection unit 102 uses the amplified signal. This makes it possible to detect a minute voltage change in a narrow voltage range.
However, when this is used at a high altitude, the difference between the reference voltage (for example, 4.75 V) and the output voltage becomes too large, and if the difference from the reference voltage is amplified by the differential amplifier 401, it can be measured. A voltage exceeding the voltage width is obtained, and there is a possibility that normal operation of the navigation device 100 may be hindered.

  Therefore, this is avoided by using the second embodiment.

  That is, every time measurement is started, the elevation detection unit 102 sets the output from the atmospheric pressure sensor 11 to the reference voltage. That is, in the above-mentioned highland, measurement can be started using a voltage (3.5 V) corresponding to the actual atmospheric pressure in the surrounding area as a reference voltage. Therefore, even if the voltage is amplified through the differential amplifier 401, the voltage can be measured. A voltage exceeding the width is not obtained, and normal operation can be ensured.

  In addition, since the atmospheric pressure in the vicinity can be measured using the atmospheric pressure sensor and set as a reference voltage in this way, the altitude can be accurately calculated even when traveling at an extremely low speed (when traveling such as traffic jams).

  The above is the description of the second embodiment.

  In both the first and second embodiments, an absolute pressure sensor is used as the atmospheric pressure sensor 11. This depends on product specifications, but generally includes a measurement error of about ± 2.5%. However, it can be said that an error of about 2.5% is not a big problem in the present application in which a difference value from the reference voltage is acquired.

  Moreover, although the example which applied this invention to the vehicle-mounted navigation apparatus was demonstrated, this invention is applicable also to navigation apparatuses other than vehicle-mounted.

FIG. 1 is a schematic configuration diagram of an in-vehicle navigation device according to a first embodiment of the present invention. FIG. 2 is a diagram illustrating a functional configuration of the arithmetic processing unit 1 according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating a hardware configuration of the arithmetic processing unit 1 according to the first embodiment of the present invention. FIG. 4 is a diagram showing a hardware configuration of the CPU 21 and the atmospheric pressure sensor 11 according to the first embodiment of the present invention. FIG. 5 is a diagram illustrating a configuration example of measurement point data stored in the storage device 3 according to the first embodiment of the present invention. FIG. 6 is a flowchart of the vehicle position calculation process according to the first embodiment of the present invention. FIG. 7 is a flowchart of the elevated host vehicle position calculation process according to the first embodiment of the present invention. FIG. 8 is a diagram showing a hardware configuration of the CPU 21 and the atmospheric pressure sensor 11 according to the second embodiment of the present invention. FIG. 9 is a diagram illustrating a configuration example of measurement point data stored in the storage device 3 according to the second embodiment of the present invention. FIG. 10 is a flowchart of the elevated vehicle position calculation process according to the second embodiment of the present invention.

Explanation of symbols

100: In-vehicle navigation device,
DESCRIPTION OF SYMBOLS 1 ... Arithmetic processing part, 2 ... Display, 3 ... Memory | storage device, 4 ... Audio | voice input / output device, 5 ... Input device, 6 ... Wheel speed sensor, 7 ... Gyro sensor, 8 ... GPS receiver, 9 ... ETC communication apparatus, DESCRIPTION OF SYMBOLS 10 ... Beacon receiver, 11 ... Atmospheric pressure sensor, 21 ... CPU, 22 ... RAM, 23 ... ROM, 24 ... DMA, 25 ... Drawing controller, 26 ... VRAM, 27 ... Color palette, 28 ... A / D converter, 29 ... SCI, 30 ... PIO, 31 ... Counter, 32 ... D / A converter, 33 ... Bus, 101 ... Main control unit, 102 ... Elevation detection unit, 103 ... Virtual current location calculation unit, 104 ... Current position determination unit, 105: Display processing unit

Claims (5)

A navigation device mounted on a vehicle,
A position detection device for detecting a current position of the vehicle;
An altitude detecting device for detecting the altitude of the vehicle;
A display device mounted in the vehicle and displaying a current location using a map;
Elevation detection means for determining elevating of the road running from the amount of change in altitude detected by the altitude detection device,
Current position determining means for obtaining a current position on the road that most matches the lifting information determined by the lifting detection means;
Current position display means for displaying the current position obtained by the current position determination means on the display device;
A navigation device comprising: A navigation device mounted on a vehicle,
A position detection device for detecting a current position of the vehicle;
A display device mounted in the vehicle and displaying a current location using a map;
An atmospheric pressure sensor,
Voltage difference acquisition means for detecting a difference between a voltage obtained as a result of measurement by the atmospheric pressure sensor and a predetermined reference voltage;
Elevation detection means for determining elevating of the road running from the amount of change in altitude detected by the voltage difference acquisition means,
Current position determining means for obtaining a current position on the road that most matches the lifting information determined by the lifting detection means;
Current position display means for displaying the current position obtained by the current position determination means on the display device;
A navigation device comprising: The navigation device according to claim 2,
The predetermined reference voltage used in the voltage difference acquisition unit is determined based on a voltage measured at a specific measurement point.
A navigation device characterized by that. The navigation device according to claim 3,
And a storage device connected to the navigation device,
The storage device stores the specific measurement point,
The predetermined reference voltage used in the voltage difference acquisition unit is determined based on a voltage measured at the specific measurement point stored in the storage device.
A navigation device characterized by that. A current location display method for a navigation device mounted on a vehicle,
The navigation device
A position detection device for detecting a current position of the vehicle;
An altitude detecting device for detecting the altitude of the vehicle;
A display device mounted in the vehicle and displaying a current location using a map;
With
Elevation detection step for determining elevating of the road running from the amount of change in altitude detected by the altitude detection device,
A current position determination step for obtaining a current position on a road that most matches the lift information determined in the lift detection step;
A current location display step of displaying the current location identified in the current location determination step on the display device;
The present location display method of the navigation apparatus characterized by performing.

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