JPH03108609A - Current position displaying apparatus for moving object - Google Patents

Abstract

PURPOSE:To display the current position of a moving object at all times with good accuracy by selecting a GPS (global positioning system) satellite in a satellite navigat ing means among a combination of satellites from which extracted improper satellites are removed. CONSTITUTION:Output values of a direction sensor 12 and a distance sensor 13 are sequentially integrated and added by a CPU 1 in accordance with the movement of a vehicle, so that the current position of the vehicle is presumed through operations. Then, the distance between a GPS satellite and the current position of the vehicle is calculated when the waves emitted from the GPS satellite are received by a GPSRx 22. As a result, a measuring position of the vehicle is obtained. In measuring the position by GPS, improper satellites the measuring accuracy of which may be prone to be deteriorated are removed and a plurality of remaining satellites are selected. When a positional information is received from an antenna at the road side by a beacon Rx23 during the running time of the vehicle, the current position of the vehicle is changed to the position represented by the information, and at the same time, the satellites the measuring accuracy of which may be reduced if used for the GPS measure ment are extracted and registered as improper satellites. Therefore, the improper satellites are not used for a predetermined succeeding time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a current location display device for a moving body suitable for navigation systems and the like.

(Prior art) Conventionally, as this type of device, for example, Japanese Patent Application Laid-open No. 61-19
The one described in the 8074 publication is known, and in this example, the GPS (Groba
l Pos it i on i ngSyst
em) Select 3 or 4 satellites from the satellites and
In addition to calculating the current location of the mobile object in dimensional or three-dimensional coordinates, the criteria for selecting a satellite in this case is to use a DO that shows geometric accuracy divergence in order to increase the positioning accuracy.
The configuration is such that the 711th satellites are selected in a combination that minimizes the P value.

(Problem to be solved by the invention) However, in the conventional device as described below, the DOP
The value is an index value determined only by the satellite placement situation and does not take into account the following errors.

(1) Errors caused by satellite position data.

(2) Error caused by ionospheric radio wave propagation delay.

(3) Error due to tropospheric radio wave propagation delay.

Therefore, there is a problem in that the combination of satellites with the minimum DOP value is not necessarily the optimal combination of satellites.

The present invention has been made in view of the problems mentioned in -1- above, and an object of the present invention is to provide a current location display device for a moving object that can always calculate the current location with high accuracy.

(Means for Solving the Problems) In order to solve the above problems, the present invention is configured as shown in FIG. The satellite navigation means a selects a plurality of GPS satellites from the list and calculates the current location of a mobile object by receiving radio waves emitted from the selected GPS satellites.

The reference position setting means sets the reference position of the current location of the mobile object based on the map matching method and the position information from the roadside antenna.

Furthermore, when the reference position is set, the selected satellite-specific current position positioning calculation means C selects a GPS satellite by changing the combination of satellites from among the plurality of receivable GPS satellites, and selects a GPS satellite by changing the combination of satellites from among the plurality of receivable GPS satellites. The current position of the mobile object is calculated using the satellite navigation means a at each time.

Furthermore, the defective satellite extracting means d is based on the difference value between the reference position set by the reference position setting means described in -1 and the positioning position calculated by the current position positioning calculation means C for each selected satellite. defective satellites have been extracted.

Then, the satellite navigation means a selects GPS satellites in combination excluding the defective satellites extracted above.

(Operation) In this invention, defective satellites with deteriorating positioning accuracy are extracted, and a combination of excluding the extracted defective satellites is used to perform GP
Since the current location of the mobile object is determined by selecting the S satellite, the accuracy of positioning the current location obtained by the satellite navigation means is improved.

(Explanation of Examples) Next, embodiments of the present invention will be described based on the drawings.

FIG. 2 is a block diagram showing the electrical hardware configuration of a vehicle route guidance device to which the present location display device for a moving object according to the present invention is applied.

As shown in the figure, this device is centrally controlled by a microcomputer centered on the CPUI.
The system t1 bus 2 includes an I10 controller 3 and a 4.5C8I controller 5, a graphics
The o-ra 6, V-RAM 7, ROM 8, D-RAM 9, Kanji ROM10 and backup RΔMll are connected.

So, the direction sensor 12 is connected to the I10 controller 3.
The MP 14 and the A/D converter 15 are connected to each other, and the distance sensor 13 is also connected thereto.

Further, the 10 controller 4 is connected to keys 16 for various input operations to the device, and a speaker 17 is connected via a sound generator 18.

On the other hand, the 5C8I controller 5 and the Taraphic controller 6 each have a CD-ROM 9 and a CRT.
20 are connected.

VDT (Visual Display Term)
The CRT 20, which functions as a computer, mainly provides driving route guidance to the destination for vehicle occupants, etc., and the image information to be displayed on this CRT 20 is V-RA.
The map information to be written to the M7 and displayed on the CRT 20 is stored in the CD-ROM 19.

In addition, in this embodiment, the detection of the current position in both directions uses a dead reckoning means obtained by successively integrating and adding unit movement components obtained from the outputs of the direction sensor 12 and the distance sensor 13. Satellite navigation means are also used to calculate the distance between the GPS satellite and the vehicle's current location by receiving radio waves emitted from the GPS satellite, and calculate the vehicle's current location based on this. It is obtained by receiving position information spot-transmitted from an antenna with a beacon Rx23.

Further, the entire device is controlled by executing a system program stored in the ROM 8 using the CPUI.

Next, FIG. 3 shows the control progera t stored in the ROM 8,
This is a flowchart showing the configuration of this embodiment, and the processing procedure of this embodiment will be explained below according to this flowchart.

In FIG. 3, when the progera 1 is started, an initial setting process is performed by input operation using the key 16 (step 100), and when the initial position of the vehicle is manually set by this process, the surrounding area is displayed on the screen 1- of the CRT 20. The vehicle's current location will be displayed together with the map (step 110).

Here, the human power at the initial position is the satellite navigation means GI'5R.
It is also possible to omit it by manually determining the positioning position calculated by x22.

When the initial setting process and the current location display process are completed in this way, the device enters the operating state, and the current location of the vehicle is estimated by sequentially integrating and adding the output values of the direction sensor 12 and the distance sensor 13 as the vehicle moves (step 120).

Next, the radio waves emitted from the GPS satellite are transmitted to GPSRx22.
The distance between the GPS satellite and the current location of the vehicle is calculated by receiving the GPS satellite, and the measured location of the vehicle is obtained (step 130).

In addition, in the GPS positioning in step 130, as will be described later, satellites (defective satellites) that may cause a decrease in positioning accuracy when used for GPS positioning are excluded from among the receivable GPS satellites, and satellites are selected from among the remaining satellites. This is done by selecting three or four satellites (three satellites are required for two-dimensional positioning and four satellites are required for three-dimensional positioning).

By the way, the respective position information obtained in step 120 and step 130 are obtained by different means. Therefore, in the next step 140, a more accurate estimated position is obtained by filtering the stiffness.

As a method for this filtering process, the well-known Kalman filter method and MINI-
Although the MAX algorithm method etc. can be used, these processing methods will not be described in detail here.

Once the current location of the vehicle has been determined in this way, the displayed map is rewritten according to the movement (step 150). Then, the current location of the vehicle is displayed on the rewritten map 1-.

(Step 110).

By repeating the processing of steps 110 to 150, the table display on the CRT 20 is sequentially rewritten as the vehicle travels, and the vehicle's current location is displayed on the map L.

By the way, among the satellites used in the satellite positioning calculation in Step 130 of L-L, there are some defective satellites that cause a decrease in positioning accuracy when used for GPS positioning, including those due to the geometrical placement (DOP) of the satellite. It may be included.

On the other hand, accurate position information is spot-transmitted from roadside antennas installed near roads to vehicles traveling nearby.

Therefore, in this embodiment, while the vehicle is running, the beacon Rx2
When location information is received from the roadside antenna in step 3, the current location of the vehicle is rewritten to the corresponding location, and as described in detail below, positioning accuracy can be improved by using GPS positioning based on the accurate vehicle location information from the roadside antenna. The satellite is configured to extract a satellite whose decline is low, register it as a defective satellite, and not use it for satellite positioning for a predetermined period of time thereafter (or until position information is obtained from the antenna on the next circuit side).

The interrupt processing (INTR) when the beacon Rx 23 receives position data spot-transmitted from the roadside antenna while the vehicle is running will be described below with reference to FIG. 4.

In this process, first, the received position data is converted into map coordinates (step 200). Here, the obtained coordinates are extremely accurate because spot transmission is used. Therefore, set this coordinate position as the vehicle's current location (
Step 210).

Next, select 3 satellites from among those that can be received by satellite navigation means.
The current location of the vehicle is obtained by selecting one to four satellites and calculating the distance between the selected satellites and the vehicle (step 220).

By the way, the current location obtained through the process of step 220 includes errors caused by ionospheric radio wave propagation delays, etc., and therefore does not match the value set in step 210. Therefore, the value set in step 210 and step 2
A difference vector of the values obtained in step 20 is calculated, and the difference vector is stored in the D-RAM 9 as error data for the combination of satellites selected in the process of step 220 (step 230).

In this way, the processes of steps 220 and 230 are repeatedly performed by changing the combinations of satellites, and when the difference vectors for all combinations have been calculated (NO in step 240), the magnitude of the difference vector is determined to be a predetermined value. It is checked whether there are two or more combinations of satellites with a value of -1- or more (step 250). Here, below a predetermined value,
If there are two or more combinations of 1:, (YES in step 250), extract that combination (step 260).
. Then, it is checked whether there is only one common satellite among the extracted combinations of satellites from 2 to 1- (step 270), and if only one common satellite is found (step 270). YES), the satellite is registered as a defective satellite (step 280), and the interrupt process ends.

The defective satellite thus determined will not be used in the satellite positioning calculation in step 130 thereafter.

In this embodiment, as described in 1-1, when the reference position information about the vehicle's current location is obtained from the roadside antenna while the vehicle is running, the current location is corrected to that location, and furthermore, the current location is adjusted to the current location from among the satellites that can be received at that time. or 4 satellites,
A positioning calculation is performed for each of the selected satellites. and,
Calculate the difference between these calculated positions and the -1- reference position,
There are two or more combinations in which the difference value is greater than or equal to a predetermined value -1-, and only one of the combinations has a common GPS.
If a satellite is included, the GPS satellite is considered to be a defective satellite that deteriorates positioning accuracy, and is not selected for subsequent positioning calculations. By executing such processing and not using the satellite registered in step 280 for subsequent positioning calculations, it is possible to obtain a satellite positioning position with high accuracy.

In addition, when using the DOP value as a satellite selection criterion as in the past, depending on the geometrical arrangement of the satellite, it may be considered a defective satellite even if the reception accuracy of the satellite has not deteriorated. In this embodiment, satellites whose positioning accuracy may deteriorate if used for positioning are registered regardless of their DOP value and without any external support, so if the satellite placement changes after a predetermined period of time, it will be marked as a defective satellite. In some cases, the satellite may be removed from the registration, in which case it will be used again for positioning as a regular satellite. In this way, in this embodiment, satellites that degrade positioning accuracy are automatically registered without using DOP values, and satellites that degrade positioning accuracy are combinations are also automatically excluded.

In addition, in the processing of steps 220 to 240, positioning calculations were performed for each combination of selected satellites, but in order to reduce the negative (■) of the calculation processing or to register defective satellites with high accuracy, the DOP value was calculated in advance. The calculations may be made in advance, and the calculations in steps 220 to 240 may be performed only for combinations in which the DOP value is equal to or less than a predetermined value.

In addition, if the calculation processing capacity of the GPSRx22 is low, performing the satellite positioning calculation and the registration process of the defective satellite as shown in -1- in line 11 will have a large negative In, but in this case, the G
It is also possible to perform the process described in (1) only when the PSRx 22 is not moving.

For example, when the process is mounted on a vehicle as in this embodiment, it is sufficient to execute the process only when the vehicle is stopped.

Furthermore, if the process described in 1-1 is executed only when the vehicle is stopped or when the vehicle speed is below a certain level, the registration accuracy of the defective satellite registered in step 280 will be decreased.
If the Rx22 is mounted on a vehicle whose moving speed can be known, it is determined whether the vehicle speed is below a predetermined reference vehicle speed or not before the process in step 220, and step 222 is performed only when the vehicle speed is below the predetermined reference vehicle speed. It is also possible to perform the following processing.

Next, a second embodiment of the present invention will be described based on FIG. The basic configuration of the device is exactly the same as that of the -1-memory 1 embodiment, so its explanation will be omitted.

By the way, in the embodiment 1-Storage 1, the current vehicle position is corrected based on the reference position information spot-transmitted from the roadside antenna, and furthermore, satellites whose positioning accuracy has deteriorated are registered based on this reference position information. In this embodiment, the reference position information is obtained by determining the degree of matching between the map information stored in the CD-ROM 19 and the travel trajectory of the vehicle. A method called map matching, which requires a high reference position, is used. Note that this method of calculating the reference position by map matching is described in, for example, Japanese Patent Application Laid-Open No. 61-56.
910'j et al., please refer to them.

If a highly reliable reference position is obtained by this map matching method, the use of defective satellites is excluded based on the reference position information.

The processing procedure of this embodiment will be described below with reference to flowchart 1 shown in FIG. In this figure, the processing procedure from steps 300 to 320 is exactly the same as the processing procedure from steps 100 to 120 in FIG. 3, and the initial setting processing (step 300) and current location display processing (step 310) are completed. Then, the vehicle's current location is estimated by the dead reckoning navigation means based on the outputs of the direction sensor 12 and distance sensor 13 (step 320).

Next, matching processing is performed between the travel trajectory of the vehicle and the road shape stored in the CD-ROM 19 (step 3).
30).

Here, if it is determined that the matching result has an accuracy of 1 minute for determining the position of the own vehicle (YES in step 340), the optimum satellite selection routine from step 380 to be described later is executed. The satellite selection method is executed, and the satellite selection method is ranked, and the error amount for each satellite combination is calculated.

Note that an accuracy of 1 minute here refers to the case where a reference position with a small position estimation error is obtained at the predetermined reference position 1], for example when turning left or right at a very distinctive intersection. It is something that can be done.

Furthermore, as a result of the matching process, if a reference value with a small position estimation error cannot be obtained at the predetermined reference position 1-, and it is determined that the current location cannot be determined (NO in step 340).
, the current location is calculated by the following satellite navigation means using GPS satellites.

The four methods calculate the distance between the GPS satellite and the vehicle's current location by receiving radio waves emitted from the GPS satellite.
Obtain the measured position of the vehicle (step 350). Note that the satellites used for positioning here are a combination of satellites that are ranked by the process of step 420, which will be described later, and are estimated to have the highest positioning accuracy. However, if reception by the selected combination of satellites is not possible for some reason, the next combination of satellites will be used.

Next, since the position obtained in step 350 includes errors caused by ionospheric radio wave propagation delay, etc.,
The error is corrected by subtracting the difference vector calculated by the J'' method described later (step 360).

Once the current location of the vehicle has been determined in this way, the display map is rewritten according to the movement (step 370).
The current location of the vehicle is displayed on the rewritten map-1- (step 310).

By repeating the processes from step 31-0 to step 370 in this way, the map on screen 1- is rewritten as the vehicle travels, and the current location is displayed on map 1-.

By the way, due to the matching process in step 330]
When the current location with sufficient accuracy is determined, the following processing is performed.

First, in the process of step 380, since a highly reliable current location has been obtained through the matching process of step 330, this location is set as the reference location.

Next, using the satellite navigation means, select 3 or 4 satellites from among the receivable satellites, calculate the distance between the selected satellites and the vehicle, and obtain the current location of the vehicle (step 39).
0). The current location obtained here includes errors caused by ionospheric radio wave propagation delays, etc., and therefore does not match the reference location set in step 380. Therefore, step 3
A difference vector between the reference position set in step 80 and the value calculated in step 390 is calculated, and the difference vector is used as correction data for the combination of satellites in step 390.
- Store in RAM 9 (step 400).

In this way, the processes of steps 390 and 400 are repeatedly performed by changing the combinations of satellites from among the receivable satellites, and when the difference vectors for all combinations have been calculated (No in step 410), the difference vectors are calculated. All Jf4 in order from the smallest vector (that is, 11 vectors in order from the satellite combination with the highest positioning accuracy),
Add (-J) to the combination of satellites (step 420)
. Then, the reference position set in step 380 is set as the vehicle's current location 7 (step 430), and the process proceeds to step 370, thereby returning from this optimal satellite selection routine.

In addition, in the process of step 400, the correction data is rewritten every time a new difference vector is calculated, but a weighted average is calculated in consideration of continuity with past data, and the correction data is It is also possible to use this as correction data.

For example, if the average value of the past n difference vectors is Mn, and if a new difference vector of magnitude i is added, the difference vector MIM used as the correction value will be expressed by the following equation. .

Mn+t=(Mn x n-tA)/
(n + 1) (1) In the second embodiment, as described in 1-1, if a highly reliable current location is obtained by the map matching method, this location is set as the reference location (7), and the reception Select 3 or 4 satellites by changing the combination of satellites from among the possible satellites, calculate the GPS positioning position for each selected combination of satellites, and calculate the difference vector from the base wall position in -1- Then, the combination of satellites with a smaller difference vector is regarded as a combination of satellites with higher positioning accuracy in GPS positioning, and the satellite combinations are ranked in descending order of the difference vector.In other words, the combination of satellites with lower positioning accuracy is , the ranking is lower as a combination of defective satellites.-) If the current location cannot be set with sufficient accuracy by the j1 map matching method, the smallest of the l- difference vectors, that is, the one that is ranked and stored at that time. The current location is calculated by introducing the satellites with the highest priority, and the error in the measured position is corrected using the differential vector value of the selected satellite combination, so the current location of the vehicle is always calculated with high accuracy. It will be possible.

In addition, in the processing of steps 390 to 410, when selecting three or four satellites from among the receivable satellites, all combinations are selected, but in this case, the process ends after a predetermined number of combinations are selected. It is also possible to control the CPU 1 so as not to put a burden on it by setting restrictions such as stopping the calculation after a predetermined time using a timer.

Next, a third embodiment of the present invention will be described based on FIGS. 6 to 8. It should be noted that the basic configuration of the apparatus in this embodiment is exactly the same as that in the first embodiment, so a description thereof will be omitted.

FIG. 6 is a general flowchart showing the overall processing procedure of the third embodiment.
The processing procedures from 0 to 540 are exactly the same as the processing procedures from steps 300 to 340 in the 1-2 second embodiment, including initial setting processing (step 500), current location display processing (
When step 510) is completed, the current location of the vehicle is estimated based on the outputs of the direction sensor 12 and distance sensor 13 as the vehicle moves (step 520), and is further stored in the CD-ROM 19 along with the vehicle's travel trajectory. Performs matching processing with the road shape (step 53).
0).

If it is determined that the matching result has an accuracy of 1 minute for determining the position of the own vehicle (YES in step 540), a satellite selection routine to be described later is executed (step 560). After extracting satellites whose accuracy is estimated to decrease if used for positioning calculations, the current location is set to the position determined by matching processing.

On the other hand, as a result of this matching process, if it is determined that the current location cannot be set with sufficient accuracy (NO in step 540), the satellite positioning routine described later is executed (step 550), and the current location is determined using the satellite. This will be done using navigational means.

Once the current location of the vehicle has been determined in this way, the displayed map is rewritten according to the amount of movement (step 570).
The current location of the vehicle is displayed on the rewritten map 1- (step r510).

By repeating steps 510 to 570 as described in 1- above, the map on screen 1- is rewritten as the vehicle travels, and the current location is displayed on the map.

Next, the details of the satellite selection routine in step 560 will be explained in the seventh section.
This will be explained based on the diagram.

In this process, first, a highly reliable current location has been obtained through the matching process in step 530, so
Set this position as a reference position (step 600)
.

Next, using the satellite navigation means, select 3 or 4 satellites from among the receivable satellites, calculate the distance between the selected satellites and the vehicle, and calculate the current location of the vehicle (Step 6
10).

Note that the current location obtained here accounts for errors caused by ionospheric radio wave propagation delays and the like, so it does not match the value set in step 600. Therefore, the difference vector E between the value obtained in step 600 and the value obtained in step 610
is calculated, and the difference vector E is stored in the D-RAM 9 as error data in the combination of satellites used in the process of step 61 [1] (step 62o).
.

In this way, the operations of step 610 and step 620 are repeatedly performed by changing the combinations of satellites, and once the difference vector E for all combinations has been calculated (NO in step 630), the difference vector E for each combination of satellites is calculated. It is checked whether there are two or more combinations of satellites such that the absolute value of the vector (ii'jE1 is El>α (where α is a constant) (2) (step 640).Here, -1-If there are two or more combinations that satisfy equation (2) (YES at step 640)
Step 65o) If only one common satellite is found (YES in step 660), extract the common satellite from the corresponding combination of satellites.
Register by classifying into two types.

That is, if the maximum absolute value of the difference vector when using the satellite is 1 Enl, then if Enl < β (where β is a constant, α × β) (3) (Y in step 670
ES), register the satellite as a spare satellite (Step 69)
o), 1-If the equation (3) is not satisfied (step 670
(NO), 1! - is registered as a defective satellite (step 680).

Note that in the process of step 670, the maximum value 1Enl of the magnitude of the difference vector is compared, but the average value may be calculated and compared with β.

In addition, in the process of step 650, if a satellite with poor accuracy cannot be identified, such as when two or more satellites with poor accuracy are extracted (NO in step 660), '7
'Biei 111 or defective satellites will not be registered.

If the above process 1- is completed, the base position set in the process of step 600 is set as the current location (step 700), and the routine returns from this routine.

Next, Mae JJ/I! of step 550 in FIG. 1
The details of the routine will be explained based on FIG.

Here, first, it is determined whether positioning is possible without using the defective satellite registered as described in 1-1 or T-Bieishu (step 800). In other words, it is determined whether the total number of I-Ga stars currently receivable, excluding defective satellites and spare satellites selected by the 1° satellite selection routine, is sufficient to calculate the current location (for two-dimensional positioning). (3 satellites are required for 3D positioning, and 4 satellites are required for 3D positioning)
If positioning is possible (YES in step 800), perform positioning calculations without using the defective satellite or spare satellite (step 81.0), set the determined position as the current location (step 840), and return from this routine. .

On the other hand, 1) γ
If it is impossible to do so (NO in step 800)
Next, it is determined whether positioning is possible without using the defective satellite (step 820), and if positioning is possible (YES in step 820), the combination of satellites excluding the defective satellite (7/IIq position) is determined. performing a forward position (step 830);
The measured γ position is set as the current location (step 840).

If the position aIlJ is not possible without using a defective satellite (NO in step 820), positioning is performed by satellite navigation means and set in 1' as the entire position Jfflffl calculated in the process of step 520 ( Step 850)n In the third embodiment, as described in 1-1, once a highly accurate reference position for the vehicle's current location is obtained by the map mapping method, the positioning position is determined by changing the combination of satellites selected by the satellite navigation means. Calculate, 1U reference position and Mae J
A difference vector of the calculated position is obtained by changing the combination of ij.

Here, if two or more combinations in which the magnitude of the difference vector is greater than or equal to the predetermined value α are obtained, and only one common satellite is obtained among these combinations, then The maximum value of the difference vector in the 1-note grouping is compared with a predetermined value β (however, α × β).
i? 1 if 't is less than β. The common satellite is registered as a Y-prepared satellite, and if β is less than -1, it is registered as a defective satellite.

Then, in the subsequent positioning calculation of the current location by satellite navigation means, T-Bieisai, Fur1? 'i'i
If it is possible to calculate the position without using stars, calculate the current location using a combination of satellites excluding those satellites, and if there are few satellites that can be received and you have to select H Sei-Ei-Ashi or a defective satellite, Since the missing satellites are selected in the order of P-bye-early and defective satellites to make up for the missing satellites, the use of E-11 that is inaccurate can be prevented as much as possible, and the current location of the vehicle can always be calculated with high accuracy.

(Effects of the Invention) The current location display device for a moving body according to the present invention has the following advantages:1. As described above, the system is configured to extract defective satellites with deteriorating positioning accuracy and select GPS satellites in combination with the extracted defective satellites, so the current location of a mobile object can always be displayed with high accuracy. What does the effect of 41 speed do?

[Brief explanation of drawings]

Fig. 1 is a claim correspondence diagram of the present invention, Fig. 2 is a block diagram showing the basic configuration of the first embodiment to which the present invention is applied, and Figs. 3 and 4 are processing procedures of the first embodiment. FIG. 5 is a flowchart 70-1-1 showing the processing procedure of the second embodiment, and FIG. 6 is a general flowchart 1-1 showing the processing procedure of the third embodiment. Figure 7 is a flowchart 1 showing the details of the engineering selection routine in Figure 6.
. . , FIG. 8 is a flowchart showing details of the satellite positioning routine in FIG. 6. 1...CPU 7...V-RAM 8...ROM 9...D-RAM 12...h' position sensor 13...distance sensor 19...CD-ROM 2O... CRT 22-GPSRx 23... Beacon Rx

Claims (1)

[Claims] 1. Satellite navigation in which a plurality of GPS satellites are selected from among receivable GPS satellites and the current location of a mobile object is calculated by receiving radio waves emitted from the selected GPS satellites. a reference position setting means for setting a reference position of a current location of a mobile object based on a map matching method or position information from a roadside antenna; Multiple GPs possible
Selected satellite current location positioning calculation means for selecting a GPS satellite by changing the combination of satellites from among the S satellites, and calculating the current location of a mobile object using the satellite navigation means for each selected combination of satellites; A defective satellite extraction means for extracting defective satellites based on a difference value between the reference position set by the reference position setting means and the positioning position calculated by the selected satellite-specific current position positioning calculation means; A current location display device for a mobile object, characterized in that GPS satellites are selected in combination excluding the defective satellites extracted above.