JPH0480679A - Apparatus for detecting position of moving body - Google Patents

Abstract

PURPOSE:To display the position of a moving body with high accuracy by employing the data processing system of hybrid satellite navigation and inputting altitude data to the two-dimensional position of the moving body obtained by the data processing thereof. CONSTITUTION:A hybrid type position measuring means 3 calculates a measuring position from both of satellite navigation receiving the dummy distance data from a satellite and the position data signals of respective satellites to measure the position of a moving body V and dead reckoning measuring the position of the moving body V from the data of the azimuth sensor and range finder mounted on the moving body V. A GPS operational processing part 2 calculates the three-dimensional coordinates position of the moving body V from three satellites. When there is large difference between altitude data and the altitude data of an altitude memory means 5, new altitude data is inputted to a GPS operational processing part 2 and operation is repeated so as to allow the altitude data on a map to gradually approach the altitude data calculated next to detect the present position.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is capable of providing altitude information by inputting altitude information to measured position data of a moving object obtained using satellite navigation, dead reckoning navigation, etc.
The present invention relates to a position detection device for a moving body that increases position detection accuracy and displays the current position with high reliability.

[Conventional technology] GPS (Global Positioning)
A positioning device for the System) usually receives three or more satellites at the same time, and measures the position of the receiving point from pseudorange data that includes the receiver's time offset between each satellite and the receiving point, and the position data of the receiving satellite. is configured to display. That is, the mobile body simultaneously receives radio waves from a plurality of satellites and calculates the position of the mobile body based on pseudorange data including a time offset between each satellite and the mobile body and the position data of each satellite. Specifically, we add the time T that matches the satellite clock as another unknown, and add △tu to the three unknowns related to the position (Xu, yu, Zu).
and 4 unknowns (Xu, 3'u, Zu, △1.
) need to be solved. To do this, it must receive radio signals from four satellites scattered in the sky. Since the height of a moving object such as a car rarely changes, even if there is a slight error in height, the two-dimensional position of latitude and longitude is unlikely to be significantly deviated. Therefore, the height 2 is filled with known numbers, and 3 unknown numbers (xu, 3'u2△1u
) is solved to obtain three-dimensional positioning.

When driving a car in an area where there are many shielding objects and radio interference between the sky and the topography and driving environment, such as mountainous areas or urban areas, where the topography and driving environment change rapidly, it is difficult to constantly receive signals from three satellites. It is not always possible to receive signals, and in many cases it is possible to receive signals from only two satellites.

Sometimes, there may be no reception at all. To this end, in addition to GPS navigation devices, devices (
It is equipped with a dead reckoning navigation system. When the number of satellites that can be received becomes two or less, the vehicle's position is calculated by a dead reckoning navigation device.

In general, GPS navigation devices have higher positioning accuracy than other navigation devices, such as dead reckoning navigation devices. The more dispersed the satellites in the sky that can be received, the higher the accuracy of positioning. However, the geometric precision divergence GDOP (Di
position of Precision) (or PDOP indicating three-dimensional positioning accuracy)
Dilution of Precision
HDOP showing horizontal precision divergence; Horizonta
lDilution of Precision)
When the positioning accuracy exceeds a certain level, the dead reckoning navigation device has higher positioning accuracy. In such a reception state, the GPS navigation device interrupts positioning, and the dead reckoning navigation device calculates the position of the vehicle.

[Problem to be solved by the invention]

Conventional position detection devices for mobile objects are configured as described above, so when a car is driving in an area with rapid changes in topography and driving environment, the GPS navigation device detects the reception level of satellite signals during positioning. This may cause a large error in the positioning results. Furthermore, when a car passes through a tunnel, the GPS navigation device does not perform positioning for a long time, and the dead reckoning navigation device performs positioning for a long time, resulting in cumulative errors.

When these situations occur, there is a problem that the position may be significantly different from the position previously measured by the GPS navigation device.

This invention was made to solve the above-mentioned problems, and it adopts a hybrid satellite navigation data processing method that provides continuity between each measurement value and improves reliability. An object of the present invention is to obtain a position detection device for a moving body that displays the position with high accuracy by inputting altitude information to the obtained two-dimensional position of the moving body.

[Means for Solving the Problems] The mobile object position detection device according to the present invention first assumes altitude data of the mobile object and inputs it as a fixed value, and calculates the three-dimensional position coordinates of the mobile object from three satellites by calculation. The measured position is determined by a GPS calculation processing unit, satellite navigation to determine the position of the moving object from the pseudo distance data obtained by the GPS calculation processing unit, and dead reckoning navigation which measures the position of the moving object from a sensor mounted on the moving object. A hybrid position measuring means, a map information storage means for storing map data on which the moving object is traveling in an external memory, reading out the map data and outputting the position of the moving object to the superimposed display means, and the map information storage means. Correlate the coordinate position obtained from the coordinate position with the altitude data of that coordinate position, and when the altitude data error becomes large, input new altitude data of the coordinate point and repeat the calculation to bring the current position asymptotic to the coordinate position of the map information storage means. The system also includes advanced information storage means.

[Operation] The GPS calculation processing unit in the present invention performs calculations by inputting altitude data assumed to obtain three-dimensional position coordinates of a moving object from three satellites. The coordinate position resulting from the calculation is superimposed and displayed on the map information storage means, and the altitude data of the coordinate position is compared with the altitude data of the altitude information storage means.

At that time, if there is a large difference between the assumed altitude data and the altitude data in the altitude storage means, the current position of the moving object is different from the position on the map, so the new altitude data obtained by calculation is sent to the GPS calculation processing unit. The current position is detected by repeating calculations to asymptotize the altitude data on the map and the altitude data obtained next.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 1 is a satellite signal receiving antenna, 2 is a GPS
3 is a hybrid position measuring means that calculates a measured position using both satellite navigation and dead reckoning navigation; 4 is a control means; and 5 stores data that correlates the relationship between the position and the altitude of the moving object. 6 is a map information storage means for storing map data in an external memory such as an IC card or CD-ROM, and is capable of reading and displaying the map data; 7 is an operation means for operating the device; 8 is a CRT, etc. This is a means of displaying.

Next, the operation will be explained with reference to the schematic diagram shown in FIG. 2 and the flow chart shown in FIG. First, the hybrid position measuring means 3 performs satellite navigation, which measures the position of the mobile object ■ by receiving pseudorange data from satellites and position data signals from each satellite, and a direction sensor mounted on the mobile object ■. The measured position is obtained from both the data and dead reckoning navigation which measures the position of the moving body V using the distance meter data. on the other hand,
The GPS arithmetic processing unit 2 determines the three-dimensional coordinate position (Xu, yu, Zu) of the mobile object (2) from the three satellites.

For this purpose, the pseudo distance R from the four satellites to the mobile body V
Measure i.

Ri=Ri+ (△t A r + C(△tu
−△t g, )...(1) Ri= ((X*+ Xu ) ” +
(3's+-yu) 2+ (Z *+-X
u) ”) ””...(
2) Here, R1: The measured distance between satellite i and the receiver (it is called a pseudorange because it contains the offset value of the clock). R1: The distance between satellite i and moving object V. C: The speed of light △ tAI; propagation delay of satellite i or satellite-type waves in the ionosphere and troposphere.

Δtu: Offset of mobile clock Δt8. ; Offset of the clock of satellite i X Ii + 3' all Z II : Three-dimensional coordinate position of the satellite position;
yu, Zu). At this time, four (xu, y
There are three pseudoranges (R,,R
Since only 2°R3) can be measured, only three equations can be created. Therefore, the values of the unknowns (Xu, yu, Zu, Δ1,) cannot be determined. Therefore, the GPS calculation processing unit 2 uses the altitude data Z among the four unknowns. are treated as fixed values and three equations for three unknowns (X8°3'LllΔ1.) are solved to find the values of Xu + yu and Δtu (step 5T1). The obtained position is displayed on the display means 8 in correspondence with the data in the map information storage means 6 (step 5T2). At this time, if the fixed value initially given to the altitude data Z8 changes, the solutions of the three simultaneous equations will naturally change as well. Therefore, for convenience, the moving body V
Assuming that there is a person, altitude data Zu is manually input and calculations are performed (steps ST3, 5T4A). Therefore, if the moving object (2) is actually at a position of 100 m above sea level, an error Z in the altitude data will occur in the calculation result, so the coordinate position obtained by calculation is superimposed on the map in the map information storage means 6. Then, the altitude data of the coordinate position on the map, that is, the altitude data stored in the altitude information storage means 5, is compared with the altitude data Zu assumed and inputted earlier (Step 5T5). Step 5T6). At this time, if the terrain and road conditions around the moving body V approximately match the information stored in the map information storage means 6 (step 5T7), the coordinate point of the current position assumed from the altitude data is End the search as correct (step 5T8)
.

In addition, if the calculated coordinate position and the current position of the mobile object (deviate from each other), the altitude data in the altitude information storage means 5 is obtained from the coordinate position on the map information storage means 6, and the new altitude The data is applied again to the three-dimensional side position using three satellites 1 to 3 (Step 5T9), and the next altitude data is searched based on the coordinate position obtained for the second time (Step 5T9).
T4B). Based on the relationship between the coordinate position of the newly obtained altitude data and the current position on the map, we repeatedly search for a point that matches the current position of the mobile object ■, and finally find the coordinate position on the map and the current position of the mobile object ■. Asymptote the position.

〔Effect of the invention〕

As described above, according to the present invention, the altitude data assumed to obtain the three-dimensional position coordinates of a moving body using three satellites is input to the GPS calculation processing unit, the calculation is performed, and the position coordinates of the calculation result are calculated. is superimposed on the map information storage means, and on the other hand, the position coordinates are compared with the altitude data in the altitude information storage means, and if the altitude error data is large, new altitude data is stored in the GP.
The map data is input to the S calculation processing unit, the map data is compared with the current position, and calculations are repeatedly executed to bring the data closer to each other.
Since only three satellites need to be selected, calculations are simplified and processing time is shortened, and real-time processing becomes possible, which greatly improves onboard effectiveness. Furthermore, since positioning can be performed using three satellites, there are advantages such as fewer interruptions in positioning than when four satellites are used.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of a position detecting device for a moving body showing an embodiment of the present invention, Fig. 2 is a conceptual diagram for explaining the invention, and Fig. 3 shows the operation order of Fig. 1. It is a flowchart explaining. In the figure, 2 is a GPS calculation processing section, 3 is a hybrid position measuring means, 5 is an altitude information storage means, 6 is a map information storage means, and 8 is a display means. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Patent applicant: Mitsubishi Electric Corporation

Claims (1)

[Claims] A GPS arithmetic processing unit that first assumes and inputs the altitude data of a moving object and calculates the three-dimensional position of the moving object from three satellites, and calculates the position of the moving object from the pseudo distance data obtained by the GPS arithmetic processing unit. A hybrid position measuring means that determines the measured position by satellite navigation and dead reckoning that measures the position of a moving object from a sensor mounted on the moving object, and a hybrid position measuring means that stores map data on which the moving object is traveling in an external memory, and stores the map data on the moving object. a map information storage means for reading out and outputting it to a display means to overlap it with the position of the moving body; and a map information storage means for matching the coordinate position obtained from the map information storage means with the altitude data of the coordinate position, and when the altitude data error becomes large, the above-mentioned A position detecting device for a moving object, comprising an altitude information storage means that inputs new altitude data of a coordinate point into a GPS calculation processing section and repeats the calculation to asymptotically approach the current position of the moving object to the coordinate position of the map information storage means.