JPS634399A - Gps position measuring apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a GPS system useful for use in a vehicle route guidance device.
Regarding position measurement equipment.

[Prior art] The GPS position measuring device is an artificial one! ! By transmitting radio waves from 17 stars to one FJrI satellite necessary for positioning, the distance between each satellite and each aircraft, ship, vehicle, or other object to be measured can be measured, and its location can be determined. However, its principle, method, etc. are described in Japanese Patent Application Laid-Open No. 1986-15.
No. 573, Institute of Electronics and Communication Engineers Technical Research Report Vol. 1, 84. Demon 78. SΔNE84-12, automatic intermediate clamp Vi1985.
Vol, 39-1 (i near ii 4 navigation global
Familiar with positioning systems) etc.

By the way, conventional GPS positioning measurement involves creating a predetermined combination of satellites from a large number of satellites orbiting in the sky.
DOP (Dilutio
It is configured to calculate n of Precision fi, receive satellite radio waves for the satellite combination that provides the minimum DOP value, and perform two positions on the measured (!) field.

However, with conventional GPS position measuring devices such as those mentioned above, as the topography changes as the target object moves, the satellite radio waves are blocked by the shadows of wild animals and mountains, making it impossible to receive information about the selected Wi star. In many cases, it was difficult to perform stable positioning.

[Object of the Invention] It is an object of the present invention to provide a GPSfS2 position measurement device that can improve the above-mentioned problems and perform stable positioning regardless of topographical changes.

[llll of inventions! Main Point 1 In order to achieve the above object, in this invention, as shown in FIG. 1, the GPS position measuring device is equipped with a shielding condition storage means that stores state data of radio wave shielding around the vehicle for each section in which the vehicle travels. 1, a condition search means 2 for searching the condition data for each section, a satellite selection means 3 for selecting the optimum satellite under conditions of good visibility based on the searched condition data, and and a position calculation means 4 for calculating the position of the vehicle using satellite data,
By using data on the state of radio wave shielding according to the travel route, the satellite was always selected under conditions with good visibility.

[Example 1 Hereinafter, the present invention will be described in detail using the accompanying drawings.

First, about the drawings! To simply explain, Figure 2 shows G
A block diagram of a route guidance device for a vehicle with a PS reception face;
FIG. 3 is an explanatory diagram showing the memory map of the external memory and the data format of road data; FIGS. 4 and 5 are explanatory diagrams of shielding conditions; FIG. 6 is a flowchart showing current position correction processing by GPS; 7 and 8 are explanatory diagrams of satellite orbits.

As shown in FIG. 2, the vehicle route guidance device includes a system bus 5, a GPS receiver 6, a CPU 7, a system ROM 8, a RAM 9, and a sensor interface 10.
, a video RAlvllll, an operation panel interface 12, an input operation section 13, and an external memory 14 are connected. Senry Interface 10
A distance sensor 15 that outputs a pulse signal a predetermined number of times each time the vehicle travels a certain distance, and a direction sensor 16 that outputs a signal indicating the direction in which the vehicle is traveling are connected to the vehicle.

A CRT 17 is connected to the bidet 71-RAM II. The operation panel interface 12 includes a transparent operation panel (touch panel) 1 provided on the front of the CRT 17.
8 are connected.

The GPS receiver 6 has inside thereof the satellite selection means 3 and the proximity calculation means 4 shown in FIG. Based on this, a predetermined number of satellites necessary for position calculation are selected from a limited area, and positioning processing of a predetermined dimension is performed.

The number of satellites required for positioning is 3 for 2-dimensional positioning and 4 for 3-dimensional positioning. Furthermore, the optimal combination of satellites is determined by the combination that minimizes the D OP value.

Based on the program stored in the system ROM, the CPU 7 calculates the estimated (V4 minute) position, corrects the estimated position, searches for data indicating the occlusion state for WI star selection, and performs various other guidance processes. This is what we do.

The distance sensor 15 has a constant R every time the vehicle travels a certain distance.
Outputs a pulse signal. The direction sensor outputs a signal indicating the direction in which the vehicle is traveling. The CPU 7 inputs these signals via the sensor interface 1o, detects the movement vector of the vehicle or its scalar, calculates the current position of the vehicle by summing the movement vector to the reference position, and calculates the current position of the vehicle based on this position. It provides route guidance. However, the recommended position obtained in this manner is adjusted as needed based on the current position detected by the GPS receiver 6.

The CRT 17 is for displaying information and the like. The operation panel 18 is used to input the starting point and destination. The input operation unit 13 is formed by a so-called keyboard, and various commands can be issued by using the 12 functions of the keyboard.

The contents stored in the external memory 14 are shown in FIG.

As shown in the figure, the memory 14 includes a road data storage area M1.
, topography (sea, river, railway) data storage area M2, point (public facilities, etc.) data storage area M3, intersection data storage area M4, character data storage area M5, area name search data storage area M6. , contains. All of these data are necessary for route guidance, but since only the road data is directly related to the implementation of the present invention, only this data will be described in detail.

The road data includes the X and Y coordinates of the starting point Ps and Ii point Pd of each line segment or i, which is obtained by subdividing the actual road and approximating a straight line, as well as data indicating the road type and the shielding state of the section (mM condition).
are stored sequentially for each line segment. Map 19 is (1-
1), (1-2), . . . are divided into blocks for convenience of search.

The data serving as the shielding condition is the data of the radio wave shielding state in the line segment 1i, and is obtained as follows.

First, as shown in FIG. 4, at the intermediate position of the line segment length i, for example, the elevation angle θ of the apex of an object that blocks satellite radio waves, such as a mountain 20, 21 or a building 22, is determined for each of the 8 equally divided directions. Next, this is applied to the angular region obtained by dividing the range from O to 90 degrees into approximately 16 equal parts, and is expressed as a 16-stage index value from O to F (hexadecimal), as shown in Figure 5. , east, southeast;
Express in 8 digits in the order of south, southwest, west, and northwest.

The index value is determined as follows according to the elevation angle θ of the apex of the object.

0~5.6°...0~11.2°...1~16
．． 8°...2 to 22.4°...3 to 28. O'・
...4 ~ 32.6°...5 ~ 38.2°...6
~43.8°...7~49.4°...8 ~56.
0°...9~61.6°...A ~67.2°・
...B~72.8°...C~78.4°...D~8
4. O'...E ~90.0'..." Therefore, for example, if the data expressed in 8 digits is "18112699J," this data (well, in that section, there are mountains, buildings, etc. that block radio waves) The elevation angle θ of the apex of the object is north, bundle, index 1 (5,6° to 11.2°) in the southeast direction, index 2 (11,2° to 16.8°) in the south direction, and index in the southwest direction. 6 (32,6°~38.2°), indicator 8 (4
3.8° to 49.4°), towards the west and north-west direction indicator 9 (
49.4° to 56.0°).

When providing route guidance, the CPU 7 recognizes the section Ili in which the own vehicle is traveling, searches for shielding condition data in the section Ili at the same time as it enters the section Ili, and uses this data as a satellite of the GPS receiver 16. This is provided to the selection means 3.

Next, an application example of the data serving as the shielding condition will be explained using FIGS. 6 to 8.

In FIG. 6, steps 602 to 607 are particularly related to shielding conditions.

Step 601 is to judge whether the current setting mode is the departure point registration mode or not. If it is the departure point registration mode, the process moves to step 608, and if it is a mode other than the registration mode. The process moves to step 602. Departure point registration mode is a mode provided for setting various guidance conditions such as departure point and destination at the departure point regarding route guidance. Since the position is not recorded in σ, the process moves to step 608.

In step 608, three satellites are selected from among all directions, and the process proceeds to step 609 and subsequent steps, which will be described in v2.

In step 602, current position data (X, Y) is read from the current position register.

In step 603, the map block (BX, BY) in which the current position exists has the vertical and horizontal lengths α and β, respectively.
(See Figure 3) is expressed by the integerization function as follows.

BX= INT (α/X > (
+)BY=INT (β/Y)
(2) In step 604, the road section li (see FIG. 3) where the current position exists is determined.

In step 605, shielding conditions (data) for people living in the section 1i are read.

In step 606, the elevation angle and azimuth of each satellite are read from the satellite orbit data shown in FIGS. 7 and 8. 7th
The figure shows the orbits of the satellites in the elevation direction.
, 4.6.8, 9°11.12.13), and the number of satellites is expected to be 18 in the future (1988). Figure 8 shows the horizontal Ytj star orbit for the satellite.

In step 607, satellites that do not meet the above shielding conditions are extracted.

Next, in step 609, it is determined whether there are three or more extracted satellites. Also, here, step 6
Regarding the processing input from 08, it is also determined whether the number of satellites is three or more orbits.

At step 609, 311 in the sky! If it is determined that the satellite l is not found, it is determined that positioning by GPS is no longer possible, and the process moves to step 617.
If it is determined in step 609 where the correctable flag is reset that there is a satellite in the sky that has orbited more than three times, the process moves to step 610.

In step 610, it is determined whether there are three or more receivable satellites among the selected satellites, and if three or more are receivable, it is determined that positioning is possible and the process moves to step 611. If it is not possible to receive three or more, the process moves to step 617.

In step 611, the current position (
XG, YG) and DOPfill are calculated.

In step 612, the DOP value is compared with a reference value (10), and if the DOP value is greater than 10, the positioning accuracy is determined to be poor, and the process moves to step 613.
In the following cases, the positioning accuracy is determined to be good, and a correctable flag is set in step 614.

Step 613 is to determine the registration mode of the departure point, and if it is determined that the mode is the departure point mode, it is unavoidable that the positioning accuracy is somewhat poor due to the mode. It is determined that the process is performed in step 614.
Go to and set the modifiable flag here. Also, if a mode other than the departure point mode is determined here,
Concerned that the positioning accuracy is not good, proceed to step 61.
Proceed to step 7 and reset the correction flag here.

On the other hand, if the modification flag is set in step 614, the process moves to step 615, where a current position register change (modification) process is performed.

In step 616, the contents of the current position register are transferred to the screen buffer, and this completes the unit correction work.

As described above, according to this embodiment, in steps 602 to 606 shown in FIG. 6, it is possible to set radio wave shielding conditions according to the topography as shown in FIG.
Since the satellite can be selected only under conditions of good visibility below 0.07, the possibility that the radio waves of the selected satellite will be blocked thereafter is reduced, and the stability of positioning is guaranteed.

Furthermore, as shown in Figure 3, the data serving as the shielding conditions at this time is simply summarized as 8-digit data for the azimuth areas divided into 8 equal parts, with the elevation angle of the apex of the shielding object being crested in 16 steps. Therefore, data processing is performed smoothly.

Furthermore, in this example, in step 61Q shown in FIG. 6, it is determined that reception is possible only for satellites under good visibility conditions, so only satellites with a high possibility of acquisition can be searched, and the satellite It is possible to make selections quickly and efficiently. In addition, in this example, in FIG. 6, if the mode is the σ record mode of the departure point, step 6 is immediately executed.
08 to select three satellites from all directions, but this is based on the assumption that the current position is not memorized at the departure point, and at the departure point, the ignition If the current position has already been registered, such as by memorizing the position of the satellite, the shielding conditions may be set using the registered position and satellites may be selected under conditions of good visibility. It is.

[Effect of the invention 1 As described above, according to the GPS position measuring device 2 according to the present invention, satellite acquisition can be performed under conditions of good visibility when traveling on a route, so that acquisition can be performed quickly. It is possible to perform stable positioning.

[Brief explanation of drawings]

FIG. 1 is a diagram corresponding to claims of the present invention. Figure 2 and subsequent figures show embodiments of this invention, and Figure 2 is a GPS
Block diagram of Senryo route guidance device with receiver, 3rd
The figure is an explanatory diagram showing the memory map of the external memory and the data format of the road data, FIGS. 4 and 5 are explanatory diagrams of the shielding conditions, and FIG. 7 and 8 are explanatory diagrams of satellite orbits. 1... Shielding condition storage means 2... Condition search means 3... Satellite selection means 4... Position calculation means Agent Patent attorney Yasu Miyoshi Figure 1 Satellite orbit (elevation direction) TXM Mi ( hoJr) 7th = Figure 8

Claims (3)

[Claims] (1) A shielding condition storage means that stores state data of radio wave shielding around the vehicle for each section in which the vehicle travels, a condition search means that searches the state data for each section, and a condition search means that stores the state data of radio wave shielding around the vehicle for each section; and a condition search means that searches the state data for each section; A GPS position measuring device comprising: satellite selection means for selecting an optimum satellite under conditions of good visibility; and position calculation means for calculating the position of the vehicle using satellite data from the selected satellite. (2) The GPS position measuring device according to claim 1, wherein the state data indicates the elevation angle of the apex of the shielding object for each divided azimuth region. (3) The GPS position measuring device according to claim 2, wherein the state data indicates the elevation angle of the apex of the shielding object as an index value for each predetermined angle.