JP2786309B2 - Vehicle position detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention compares and compares the positions of vehicles traveling on any part of a road traffic network by using a plurality of navigations each having a different principle. The present invention relates to a vehicle position detecting device that detects a position of a vehicle from a positional relationship.

[Conventional technology]

Conventionally, a method for detecting the position of a vehicle traveling at an arbitrary point in a road traffic network includes a distance sensor, an azimuth sensor, and a processing device that performs necessary processing on output signals from both sensors. A dead reckoning method has been proposed in which the current position data of a vehicle is obtained while integrating the distance change amount and the azimuth change amount generated as the vehicle travels.

The disadvantage of this dead reckoning is that the errors of the distance sensor and the azimuth sensor are accumulated with the continuation of traveling, and as a result, accumulated errors appear in the current position data. Considering such a problem and assuming that the vehicle travels on the road, the current position data obtained by the dead reckoning and the road traffic network data stored in the memory in advance are compared. A method for calculating the amount of deviation of the position data from the road as a cumulative error, correcting the current position data for the cumulative error, and matching the current position data with the road data is disclosed in, for example, JP-A-63-148115. A position detection method based on a conventional map matching method disclosed in the gazette has been proposed. (U.S. Pat. No. 3,789,198, JP-A-58-99715, JP-A-58-113711, and "LANDFALL A HIGH-RESOLUTION AUTOMATIC VEHICLE
−LOCATION SYSTEM "D.KING, CEC Journal of Science &
Technology, Vol. 45, No. 1, 1978) For example, in the position detection method described in US Pat. No. 3,789,198, the traveling distance data of the vehicle obtained by the distance sensor and the azimuth sensor are used. The current position data of the vehicle is calculated based on the traveling direction data of the vehicle, and the calculated current position data is compared with the road position data stored in the memory in advance. If it is within the threshold value, correct the current position data so that it is located on the nearest road, and on the contrary, do not perform any correction if the difference between the two data is greater than a predetermined threshold value. To make corrections with high accuracy as a whole,
I am trying to display the exact current position.

In the position detection method described in JP-A-58-99715, the current position data is updated by calculating a distance change component in the coordinate axis direction of the road map every time the vehicle travels a predetermined distance, and the current position data is updated. When the vehicle is off the road, an accurate current position is displayed by simply using the position data on the nearest road as the current position data.

In the position detection method described in Japanese Patent Application Laid-Open No. 58-113711, an error of an azimuth sensor for detecting a traveling azimuth based on geomagnetism is compared with a curvature obtained based on the traveling azimuth and a curvature of a road. To correct the display of the current position.

LANDFALL A HIGH-RESOLUTION AUTOMATIC VEHICLE
In the position detection method described in the LOCATION SYSTEM, the road traffic network is grasped as a non-branch portion and a plurality of typical branch portions, and the vehicle travels from one branch portion to another branch portion. Is calculated based on a signal from the distance sensor, and when it is determined that the vehicle has reached the branch portion, a change in the direction is detected by the direction sensor, and By judging whether the vehicle is heading to the branch exit, the current position of the vehicle is to be accurately displayed as a position on the road.

In addition, GPS (Global) that determines the current position of a mobile object three-dimensionally or two-dimensionally using radio waves transmitted from satellites
Positioning System) As a positioning method, JP-A-63-17
There is one disclosed in Japanese Patent Publication No. 1377. Describing the GPS positioning principle, determine pseudoranges P _i from the satellite to the mobile by first measuring the radio wave propagation time from a plurality of GPS i-th satellite of the satellite. Next, the i-th satellite position (U _i , V _i , W _i ) is obtained from the satellite orbit data transmitted by the satellite. If the coordinates indicating the position of the moving object are (X, Y, Z), the following positioning equation holds.

In the equation (1), B is an error between the clock of the satellite and the clock of the moving object, and is an unknown parameter. Since there are four unknown parameters, X, Y, Z, and B, formula (1) is set for the four satellites, and the position of the moving object is set to 3 by solving them simultaneously.
It can be obtained dimensionally. In addition, 2
For a moving object on a three-dimensional plane, two-dimensional positioning is possible using three satellites by setting the altitude to a fixed value.

[Problems to be solved by the invention]

Since the conventional vehicle position detection device is configured as described above, the absolute position of the vehicle cannot be determined by dead reckoning navigation as self-contained navigation. Also, the accuracy is not very good due to the accumulated error of the sensor. Further, in the improved map matching method, although improvement in accuracy can be expected, map data is indispensable, and as described above, the absolute position of the vehicle cannot be known.
In the case of GPS navigation, expensive equipment is required outside, and maintenance of this equipment is indispensable, and when a vehicle enters a tunnel or behind a building, radio waves are cut off, making it unusable. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has a traveling azimuth detecting means for detecting a traveling distance of a vehicle as dead reckoning navigation, a traveling azimuth detecting means for detecting a bearing, and a road storing map data. A network storage unit, and a map matching operation unit that calculates data output from each of the units and outputs a position of the vehicle, and a GPS navigation unit that calculates a position from output data of a GPS reception unit as GPS navigation. Arithmetic means and dead reckoning position and GPS
It is an object of the present invention to obtain a vehicle position detecting device that compares a navigation position with a comparing means and outputs and displays an absolute position of the vehicle on a display unit.

[Means for solving the problem]

A vehicle position detection device according to the present invention calculates an estimated current position of a vehicle using a travel distance of a vehicle detected by travel distance detection means, a travel direction of the vehicle detected by travel direction detection means, and map data. Dead reckoning means having map matching calculation means, and GPS calculation means for calculating the measured current position of the vehicle by radio waves from GPS satellites, and calculates the current position of the vehicle based on the estimated current position and the measured current position. It is to detect.

(Operation)

The vehicle position detection device of the present invention detects the current position of the vehicle based on the current position obtained by map matching and the current position obtained by GPS.
When performing map matching, it is possible to prevent map matching by mistake on a road that is not traveling.

That is, when there are a plurality of roads to be map-matched near the current position obtained by the self-contained navigation, it is not possible to determine which road should be used for map matching, and the map is matched to an erroneous road. In some cases, the use of the GPS data makes it possible to select a correct position from a plurality of current positions. In addition, even if there is only one road to be map-matched, the likelihood of map matching can be determined, and if it is determined that map matching is incorrect, the GPS data is used as the current position. By doing so, it is possible to accurately detect the current position.

(Example of the invention)

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 is a block diagram showing dead reckoning means, and information from a traveling distance detecting means 2, a traveling azimuth detecting means 3, and a road network storing means 4 which stores a road traffic network in a predetermined range in advance. And a map matching calculating means 5 for calculating the estimated position of the vehicle by using the input as the input. The GPS navigation means 6 receives radio waves transmitted from a plurality of satellites, measures the transmission time of radio waves from the satellites via an antenna 7 on the vehicle, and a pseudo distance between the satellite and the mobile body. GPS calculation means 9 for calculating by calculation
It is composed of 10 is a comparison means for comparing the data output from the dead reckoning means 1 and the GPS navigation means 6, 11
Denotes a display unit, and 12 denotes an operation unit.

Next, the operation will be described with reference to the flowchart of FIG. First, it has already been described that the conventional vehicle position detection methods include dead reckoning means 1, map matching calculation means 5, and GPS navigation means 6.

The present invention compares the data of the calculation results based on the existing navigation to detect a position with higher overall accuracy, and performs dead reckoning using the traveling distance detecting means 2 and the traveling direction detecting means 3, The range of the estimated vehicle position including the error on the map data is calculated by the map matching calculation unit 5 by superimposing the estimated position on the map data of the road network storage unit 4. This calculation result indicates a certain estimation area a including an error as shown in FIG.
When compared with the map data, the position of the vehicle is estimated to be at _{one of} the _two roads R ₁ and R ₂ , V ₁ or V ₂ .

Therefore, in the next stage, the transmission time of the radio wave from the satellite is measured, and the pseudo distance between the satellite and the vehicle is obtained. In the case of the GPS navigation, the two-dimensional position coordinates of the vehicle obtained from the GPS calculation means 9 are three satellites (A, B, C) as shown in FIGS.
Then, at one location, and at four satellites (A, B, C, D), four position coordinates G ₁ , G ₂ , G ₃ , G ₄ are obtained from the combination.

Therefore, in FIG. 4, it is checked whether or not three or more GPS satellites can be received (step ST1). If the GPS satellite can be received, the departure place is automatically input (step ST2). If reception is not possible, the user manually inputs the departure place (step ST3).

Next, four types of navigation can be considered depending on whether three or more GPS satellites can be received and the presence or absence of map data (step ST4).
~ ST6). First, when GPS satellite reception is not possible and there is no map data, the position of the vehicle is estimated by the dead reckoning navigation means 1 as before (step ST7). GPS satellite reception is not possible,
If there is map data, map matching navigation is adopted (step ST8). If GPS satellites can be received but there is no map data, the current position is corrected to the position of the GPS satellite, and if there are multiple positions, the position is corrected to the average position (step ST9). Furthermore, if GPS satellites can be received and map data also exists, the distance between each position of a plurality of combinations of the position by GPS navigation and the position by map matching navigation is calculated, and the combination of the minimum distance is calculated. position by the map matching navigation of, for example, the second view, and the road R ₂ from the relationship of V ₂ -G ₄ is correct to correct the position of the vehicle to the matching position one place (step ST10).
Matching positions with extremely low existence probability are deleted from the position coordinates obtained by GPS navigation.

〔The invention's effect〕

As described above, according to the present invention, the current position of the vehicle is detected based on the estimated current position calculated by the map matching calculation unit and the measured current position calculated by the GPS calculation unit. When matching, it is possible to prevent map matching by mistake on a road that is not traveling, prevent detection of the current position containing extreme errors, and detect the accurate current position. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a vehicle position detecting device showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing a relationship between a road traffic network and a vehicle position in the present invention, and FIG. FIG. 4 is a flowchart showing the operation of the present invention. In the figure, 1 is dead reckoning means, 2 is traveling distance detecting means, 3 is traveling direction detecting means, 4 is road network storing means, 5 is map matching calculating means, 6 is GPS navigation means, 8 is GPS receiving means, 9 Denotes GPS calculation means, 10 denotes comparison means, 11 denotes a display unit, and 12 denotes an operation unit. In the drawings, the same reference numerals indicate the same or corresponding parts.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) G01C 21/00 G08G 1/0969 G01S 5/14

Claims (1)

(57) [Claims] 1. A map matching calculating means for calculating an estimated current position of a vehicle using a traveling distance of a vehicle detected by a traveling distance detecting means, a traveling azimuth of the vehicle detected by a traveling azimuth detecting means, and map data. Dead Reckoning Means with GPS and GP that Calculates Measured Current Positions of Multiple Vehicles Using Multiple Combinations of Satellites Using Radio Waves from GPS Satellites
S calculating means, wherein the current position of the vehicle is detected based on the estimated current position calculated by the map matching calculating means and the estimated current positions of a plurality of places calculated by the GPS calculating means. Vehicle position detection device.