JP3402383B2 - Vehicle current position detection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle current position detecting device which displays a current position of a vehicle on a road map and guides an occupant to a destination. [0002] Methods for detecting the current position and heading of a vehicle include a GPS positioning method and dead reckoning navigation (or self-contained navigation). The former is a GPS transmitted from three or more satellites
This is a method of receiving a signal to detect the current position and traveling direction of the vehicle. If the accuracy of the GPS signal itself and the positional relationship between the satellite and the vehicle are good, an accurate current position and traveling direction can be obtained. On the other hand, the latter detects a traveling distance and a traveling direction of the vehicle based on various information obtained from sensors such as a vehicle speed sensor and a gyroscope, and calculates a traveling locus of the vehicle based on the data. Further, a method is provided in which a traveling route of a vehicle is specified by map matching between the calculated traveling locus and map data, and a current position is detected. In the latter dead reckoning navigation, output pulses of a vehicle speed sensor that generates a pulse signal are counted for each predetermined traveling distance, the traveling distance is detected based on the count value, and the gyroscope detects the traveling distance. The turning angle of the vehicle is calculated by integrating the turning angular velocity, and the current turning direction is detected by adding the calculated turning angle to the initially set turning direction of the vehicle. Therefore, as the vehicle travels, sensor detection errors and calculation errors accumulate. In particular, the traveling azimuth of the vehicle calculated based on the output of the gyroscope is the azimuth obtained by adding the integral value of the turning angle to the initially set azimuth, and the detection error and the calculation error of the gyroscope as the vehicle travels. Accumulate and the error increases. In order to solve such a problem, GPS
A current position detection device for a vehicle has been proposed which corrects the current position obtained by dead reckoning using the accurate current position obtained by positioning (for example, Japanese Patent Application Laid-Open No. Hei 2 (1994) -207).
No. 212714). [0005] However, GPS
There is a time lag from when the signal is received to when the current position and heading are calculated and output. If the current position of dead reckoning navigation is corrected using the current position obtained by GPS positioning, this time lag will instead cause an error in calculating the current position. There is a problem that becomes large. This problem will be described in detail with reference to FIG. FIG. 6A shows a traveling route of a vehicle and a traveling locus calculated by dead reckoning navigation. Now, it is assumed that the calculation of the current position by dead reckoning is performed for each predetermined traveling distance, and the current position indicated by a white circle is calculated on the traveling locus of FIG. Further, it is assumed that the GPS signal is received at the position a1 on the traveling route. Due to the time lag of the GPS positioning described above, the calculation result is obtained at the position a2. That is, when the vehicle reaches the true position a2 on the traveling route, the position c1 when the GPS signal is received is calculated. Here, the deviation between the GPS reception position a1 and the position c1 of the GPS positioning result is a calculation error of the GPS positioning. During this time lag, the current position is calculated for each predetermined traveling distance by dead reckoning navigation,
At the time of the true position a2 where the calculation of the GPS positioning is completed,
The current position of the position b2 is calculated by dead reckoning. In the conventional navigation device, the position a2 is determined by the GPS positioning.
Since the current position b2 obtained by dead reckoning is corrected based on the current position c1 of the calculation result obtained in the above, the corrected current position of the vehicle becomes c1 near the GPS reception position a1. That is, an erroneous correction result is obtained that the vehicle is at the position c1 even though the vehicle is at the position a2. FIG. 6B shows a time change of an error caused by GPS positioning and an error caused by dead reckoning. The calculation error of the current position by the GPS positioning is the lowest when the GPS signal is received, and thereafter, the error apparently increases with the movement of the vehicle until the next GPS signal is received. On the other hand, the calculation error of the current position due to dead reckoning is calculated when the calculation interval is GPS.
Is smaller than in the case of (1), the increase rate of the error is small, but the accumulated error increases with time. If the current position of dead reckoning is corrected when the calculation of the current position by GPS positioning is completed, the error of dead reckoning will be the same as the error of GPS positioning, and the correction will increase the error. An object of the present invention is to provide a vehicle current position detecting device which calculates an accurate current position in consideration of the influence of a time lag from when a GPS signal is received to when positioning calculation is completed. Means for Solving the Problems The present invention will be described with reference to FIG. 1 which is a claim correspondence diagram.
GPS receiving means 100 for receiving a signal, first calculating means 101 for calculating the current position of the vehicle based on the GPS signal received by the GPS receiving means 100, and distance detecting means 102 for detecting the traveling distance of the vehicle Direction detecting means 103 for detecting the heading of the vehicle, and distance detecting means 10
Second calculating means 10 for calculating the current position of the vehicle based on the traveling distance detected by the second and the azimuth detecting means 103
5 is applied to the current position detecting device of the vehicle having
After receiving the GPS signal by the S receiving means 100, the first
The time lag until the calculation of the current position is completed by the calculating means 101 is input from the first calculating means 101,
Based on the position a1 of the vehicle calculated by the calculating means 101
Then, the vehicle of the vehicle calculated by the second
Correction means 106 for correcting the position b1 to the position c1,
Based on the position c1 of the vehicle corrected by the means 106
Of the vehicle calculated by the second calculating means 105
Correction means 106 for correcting the position b2 to the current position c2;
The position a1 is provided by the GPS
The position of the vehicle at the time of receiving the signal, and the position b
1 and c1 are the GPS signals
Of the vehicle at the point in time closest to the
Positions, where positions b2 and c2 are the latest
Position of the vehicle, thereby achieving the above object. There is a time lag from when the GPS signal is received to when the current position of the vehicle is calculated by the GPS positioning calculation, and the GPS signal reception calculated by the accurate GPS positioning method in consideration of the time lag. The estimated current position calculated by dead reckoning navigation is corrected based on the current position at the time. Thereby, accurate correction of the current position is performed. FIG. 2 is a block diagram showing the configuration of one embodiment. The vehicle speed sensor 1 is attached to a transmission of a vehicle, for example, and generates a predetermined number of pulse signals per rotation of a speedometer pinion. Computer 2
Calculates the traveling speed of the vehicle by detecting the number of pulses or pulse period per unit time output from the vehicle speed sensor 1, and calculates the traveling distance of the vehicle by counting the number of pulses. [0012] The GPS receiver 3 is a GPS receiver.
It is a receiver that receives a PS signal, and detects a current position and a heading of the vehicle based on the received GPS signal. The gyroscope 4 detects the turning angular velocity of the vehicle. The computer 2 calculates the turning angle of the vehicle based on the turning angular velocity detected by the gyroscope 4, and further calculates the traveling direction of the vehicle by integrating the turning angle. Note that G
The traveling direction of the vehicle calculated based on the output of the gyroscope 4 is corrected as needed based on the accurate traveling direction of the vehicle detected by the PS receiver 3. The CD-ROM 5 is a storage device for storing road map data. The computer 2 detects the traveling distance of the vehicle by counting the output pulse signal of the vehicle speed sensor 1, detects the traveling direction of the vehicle based on the turning angular velocity of the gyroscope 4, and detects the traveling direction of the vehicle based on the traveling distance and the traveling direction. Calculate the running locus. And the running locus and C
Map matching is performed by comparing the road map read from the D-ROM 6 with the road map, and the estimated current position and the travel route are calculated by dead reckoning navigation. Computer 2 is also a GP
The current position and traveling direction obtained by GPS positioning are input from the S receiver 3, and the estimated current position and traveling direction obtained by dead reckoning are corrected. FIGS. 3 and 4 are flowcharts showing a control program executed by the computer 2. FIG.
(A) shows the traveling distance of the vehicle and the traveling locus calculated by dead reckoning. In order to make it easier to understand the differences between the present invention and the conventional example, the traveling route of the vehicle, the GPS signal receiving position, the GPS positioning calculation conditions, the calculation of the running trajectory by dead reckoning and the current position in FIG. The condition is shown in FIG.
The same as in the case of (a). With reference to these drawings, the current position calculation processing of the embodiment will be described. When the main switch (not shown) is turned on, the computer 2 starts executing the control program. First, in step S1, the vehicle speed pulse output from the vehicle speed sensor 1 is counted, and the traveling distance is detected. In the following step S2, the turning angular velocity output from the gyroscope 4 is integrated to calculate the turning angle, and the turning angle is added to the previously calculated running direction to calculate the current running direction. In step S3, the previously calculated travel locus stored in the memory 2m is read, and the travel locus to the current position is calculated based on the travel distance and the traveling direction detected this time. Then, the traveling locus is compared with road map data around the current position stored in the CD-ROM 5, and map matching is performed to estimate the current position of the vehicle. In step S4, the estimated current position and the running trajectory obtained by the dead reckoning are stored in the memory 2m to update the current position. In step S5, the cycle of the vehicle speed pulse output from the vehicle speed sensor 1 is measured to detect the vehicle speed. If the vehicle speed is equal to or higher than a preset speed, the process proceeds to step S7.
Otherwise, go to step S6. In step S6, it is determined whether or not the turning angular velocity detected by the gyroscope 4 is equal to or higher than a preset angular velocity. If the angular velocity is equal to or higher than the set angular velocity, the process proceeds to step S7; otherwise, the process proceeds to step S6. When the traveling speed and the angular velocity of the vehicle are small, the detection error between the vehicle speed sensor 1 and the gyroscope 4 becomes large, so that it is not adopted as data for calculating the traveling distance and the traveling direction. If the vehicle speed and the turning angular speed are each equal to or greater than the set value, the process proceeds to step S7, and the detected vehicle speed and angular speed are stored in the memory 2m. Next, the process proceeds to step S8 in FIG. 4, where it is determined whether the GPS signal has been received by the GPS receiver 3 or not.
If GPS signals are received from more than one satellite, step S9
Then, if the GPS signal has not been received, the process returns to step S1 in FIG. Here, the GPS at the position a1 in FIG.
Assuming that the signal is received, the GPS positioning calculation ends at the position a2 due to the time lag of the GPS positioning, and the current position c1 and the traveling direction at that position are calculated. Step S9
Then, the current position c1 and the traveling direction of the calculation result are input from the GPS receiver 3, and the process proceeds to step S10. Step S10
Then, a time lag from when the GPS signal is received to when the current position and the heading are output is input from the GPS receiver 3. This time lag is a time required for the vehicle to reach the position a2 from the position a1. In step S11, the dead reckoning navigation system detects a time lag before the current time, ie, a time point closest to the GPS signal reception time point, from the estimated position and traveling direction calculated by dead reckoning navigation stored in the memory 2m. Of the estimated position b1 and the heading direction by
The correction is performed using the position c1 and the traveling direction obtained by the PS positioning. That is, the estimated position b1 by dead reckoning at the time of GPS reception is corrected to the position c1 by GPS positioning. Further, in step S12, the G stored in the memory 2m
Guessed position b1 by dead reckoning navigation from the time of PS reception to the present
1, b12, b13, and b2 are read out, and based on the vehicle position c1 and the traveling direction at the time of GPS reception corrected in the above-described steps, the estimated positions b11, b12, and b thereafter.
13 and b2 are recalculated, and the estimated positions c11 and c1 are calculated.
2, c13 and c2 are obtained. In step S13, the recalculated estimated positions c1, c11, c12, c13, and c2 are stored in the memory 2m, and the traveling locus is updated. In the following step S14, the recalculated estimated positions c1, c11, c1
2, c13, and c2, the latest position c2 is stored in the memory 2m as the estimated current position, and the estimated current position is updated. As a result, the estimated current position c2 after the correction based on the GPS positioning result is close to the true position a2 of the vehicle as shown in FIG. 5A, and after the correction by the conventional device shown in FIG. It can be understood that the current position of the dead reckoning navigation has been accurately corrected based on the GPS positioning result as compared with the estimated current position c1 of FIG. FIG. 5B shows a time change of the error by the GPS positioning and the error by the dead reckoning according to the present invention.
This corresponds to the case of the conventional device shown in FIG. G
The time change of the error of the PS positioning is the same as that of the conventional device shown in FIG. On the other hand, when the current position calculation error by dead reckoning is corrected by the current position obtained by GPS positioning, all of the dead reckoned positions b1, b11, b12, b13, b up to the time of GPS reception are corrected.
2 is corrected, the calculation error of the current position by dead reckoning is reduced, and the current position is accurately corrected. In the above embodiment, the current position is calculated for each predetermined traveling distance by dead reckoning navigation, but the current position may be calculated at predetermined time intervals. In the configuration of the above embodiment, the GPS receiver 3 functions as a GPS receiving means and a first arithmetic means, the vehicle speed sensor 1 and the computer 2 function as distance detecting means, and the gyroscope 4 and the computer 2 function as azimuth detecting means. And the computer 2 constitute the second calculating means and the correcting means, respectively. As described above, according to the present invention, G
The estimated current position calculated by dead reckoning is corrected based on the current position calculated by the accurate GPS positioning method in consideration of the time lag from the reception of the PS signal to the calculation of the current position of the vehicle by the GPS positioning operation. As a result, the current position is accurately corrected.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram corresponding to claims. FIG. 2 is a diagram showing a configuration of an embodiment. FIG. 3 is a flowchart showing a control program of a computer. FIG. 4 is a control program and a flowchart of a computer. FIG. 5 is a view for explaining a method of correcting a current position in dead reckoning navigation based on a GPS positioning result. FIG. 6 is a view for explaining a conventional method of correcting a current position in dead reckoning navigation based on a GPS positioning result. [Description of Signs] 1 vehicle speed sensor 2 computer 2m memory 3 GPS receiver 4 gyroscope 5 CD-ROM 6 display 100 GPS receiving means 101 first calculating means 102 distance detecting means 103 azimuth detecting means 105 second calculating means 106 Correction means

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-138814 (JP, A) JP-A-3-51783 (JP, A) JP-A-2-275310 (JP, A) JP-A-2- 212714 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01C 21/00 G01S 5/14 G08G 1/0969

Claims (1)

(57) [Claim 1] GPS receiving means for receiving a GPS signal, and first calculating means for calculating a current position of the vehicle based on the GPS signal received by the GPS receiving means. A distance detecting means for detecting a traveling distance of the vehicle, a direction detecting means for detecting a traveling direction of the vehicle, a traveling distance detected by the distance detecting means, and a traveling direction detected by the direction detecting means. And a second calculating means for calculating the current position of the vehicle based on the current position of the vehicle. A GPS signal is received by the GPS receiving means, and the current position is detected by the first calculating means. A time lag until the calculation is completed is input from the first calculating means, and
1 based on the position a1 of the vehicle calculated by the first calculating means.
The position b of the vehicle calculated by the second calculating means
1 to a position c1 and a position c1 of the vehicle corrected by the first correction unit.
Of the vehicle calculated by the second calculating means based on the
Second correction means for correcting the current position b2 to the current position c2
And the position a1 is a GPS signal by the GPS receiving means.
And the positions b1 and c1 are determined by the GPS receiving means.
At the time point closest to the time point when the GPS signal was received
The position of the vehicle, and the positions b2 and c2 are the positions of the vehicle at the latest time.
A current position detection device for a vehicle, which is a position.