JPH0526678A - Gps navigation device - Google Patents

Abstract

PURPOSE:To perform correct navigation even when only two-dimensional position measurement can be made by storing the altitude data in unit areas divided with the area in the preset range in advance. CONSTITUTION:The GPS receiver 11 of this system receives the radio waves from a GPS satellite via a GPS antenna 11A and outputs the GPS position measurement data of the latitude, longitude, and altitude to a present position data output section 12. The preset area on a map is divided into multiple unit areas in advance, and the data representing the respective altitudes are stored in the CD-ROM 15 of a CD-ROM 14. A controller 13 matches the output of the output section 12 with the data M on the map and displays the present position on a display 16. When three-dimensional position measurement can not be made, the receiver 11 judges whether two-dimensional position measurement can be made, if it can be made, the present position is calculated from the received radio waves and outputted to the output section 12, the controller 13 judges the unit area to which the present position belongs based on the data, and the altitude data from the ROM 15 are used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a navigation system, and more particularly to a GPS (Global Positioning System).
The present invention relates to a GPS navigation system using a receiver.

[0002]

2. Description of the Related Art Conventionally, a GPS navigation system using an artificial satellite has been used as a navigation system for various moving bodies such as automobiles, airplanes, and ships. The GPS receiver used in this GPS navigation system normally receives radio waves from three or more GPS satellites, and pseudo range data including the time offset of the receiver between each GPS satellite and the receiving point and each GP.
The position of the receiving point is measured from the position data of the S satellite.

In this case, in order to perform two-dimensional positioning (measurement of latitude and longitude) of the moving body, three GPs are used.
It is necessary to measure pseudorange data for S satellites. This requires three measurement values in addition to the two unknowns that are mathematically two-dimensional positions, and the third unknown that is the clock offset of the GPS satellite and the clock of the receiver, that is, the time offset of the receiver. It means that
Therefore, in the GPS positioning device, 3 including altitude
When dimensional position measurement (three-dimensional positioning) is performed, the number of unknowns is four, and therefore it is necessary to measure four GPS satellites.

However, when a GPS positioning device is actually used in a moving body such as a vehicle, one of the GPS satellites is shielded by a building such as a building or a tree, and only radio waves from three satellites are received. There are things you can't do. In such a case, the GPS receiver can only perform two-dimensional positioning, and the data directly obtained is only the latitude and longitude data. Further, since the altitude data cannot be obtained, the latitude data and the longitude data also include an error.

Therefore, in the conventional GPS navigation device, when the change from the three-dimensional positioning to the two-dimensional positioning is unavoidable for the above-mentioned reason, in order to compensate the altitude data, the previous three-dimensional positioning is performed. The altitude data of 3 is held, and the previous altitude data is used to approximately obtain 3D positioning data.

FIG. 6 shows a conventional GPS navigation device.
The operation | movement flowchart is shown. First, GPS navigation
The GPS receiver (not shown) of the device is capable of three-dimensional positioning.
It is determined whether or not it is possible (step S20). 3D positioning
If possible, that is, receive radio waves from four GPS satellites.
If it is possible to communicate, the
Calculate current position (step S21), and obtain latitude data X₁,
Longitude data Y ₁, Altitude data Z₁Is output (step
S22). Next, the controller (not shown) is the latitude data.
X₁, Longitude data Y₁, Altitude data Z₁Map with
Perform processing such as matching (step S27) and display
Display the current position on the map
(Step S28), the process ends.

If three-dimensional positioning is not possible in the determination of step S20, the GPS receiver determines whether two-dimensional positioning is possible (step S23). When two-dimensional positioning is possible, that is, when radio waves can be received from three GPS satellites, latitude data X ₂ and longitude data Y ₂ of the current position are calculated from those received radio waves (step S24). Furthermore, latitude data X ₂ and longitude data Y
₂ and the altitude data Z ₁ obtained in the previous three-dimensional positioning are output as pseudo three-dimensional positioning data (step S2
5). Subsequently, the controller (not shown) performs processing such as map matching using latitude data X ₂ , longitude data Y ₂ , and altitude data Z ₁ (step S27), and displays the current position on a map (not shown) on the map (step S28). ), The processing ends.

If the two-dimensional positioning is impossible in the determination in step S23, the GPS receiver does not output the current position data (step S26), and the process ends.

[0009]

According to the above-mentioned conventional GPS navigation device, when only two-dimensional positioning can be performed, since altitude data at the time of the previous three-dimensional positioning is used, when climbing a mountain. In addition, there is a problem that the positioning error increases as the altitude of the mobile changes significantly.

Therefore, an object of the present invention is to provide a GPS navigation device capable of obtaining correct current position data and performing accurate navigation even when only two-dimensional positioning can be performed.

[0011]

In order to solve the above problems, the present invention is a GPS that receives positioning radio waves from GPS satellites, measures the current position of the moving body, and outputs GPS positioning data. The positioning means, an altitude data storage means that divides an area of a predetermined range on the map into a plurality of unit areas in advance, and stores altitude data representing an actual altitude of the unit area, and the GPS positioning means are two-dimensional. When performing positioning, the unit area to which the current position of the moving body belongs is determined based on the GPS positioning data, the altitude data corresponding to the unit area is read from the altitude data storage unit, and And a current position calculating means for calculating and outputting the current position data based on the altitude data and the GPS positioning data.

[0012]

According to the present invention, the GPS positioning means receives positioning radio waves from GPS satellites, measures the current position of the moving body itself, and outputs GPS positioning data to the current position calculation means. On the other hand, the altitude data storage means divides an area of a predetermined range on the map into a plurality of unit areas in advance, and stores altitude data representing the actual altitude of the unit areas. The present position calculation means is the GPS positioning means 2
When performing dimensional positioning, the unit area to which the current position of the moving body belongs is determined based on the GPS positioning data, and the altitude data corresponding to the unit area is read from the altitude data storage means, Current position data is calculated and output based on the altitude data and the GPS positioning data.

Therefore, even when the GPS positioning means can only perform two-dimensional positioning, the current position can always be obtained using the optimum altitude data, and accurate navigation can be performed.

[0014]

EXAMPLE An example of the present invention will be described below with reference to FIGS. FIG. 1 shows a basic configuration block diagram of a vehicle-mounted navigation system.

In the navigation system 10, the GPS receiver 11 receives radio waves from GPS satellites via the GPS antenna 11A and outputs GPS positioning data D _G including latitude data, longitude data, altitude data, etc. to the current position data output unit 12 Output to.

[0016] CD-ROM 15, as shown in FIG. 2, in advance an area AR in a predetermined range on the map MAP was divided into a plurality, for example sixteen unit areas A ₁ to A _16, the unit areas A ₁ ~ The altitude data H _{D1 to} H _D16 representing the actual altitude of A ₁₆ are stored. As these altitude data H _{D1 to} H _D16 , each unit area A _{1 to} A ₁₆ is further subdivided, and the average of the altitudes of the subdivided areas and the maximum of the subdivided areas are calculated. The most frequent altitude, which is a frequent value, can be used. Further, in FIG. 2, the predetermined area AR on the map is divided into unit areas of approximately the same area, but in areas such as mountains where the altitude changes drastically, the areas are divided finely, that is, the area of the unit area is reduced, In areas where the altitude changes slowly, the specified area on the map is divided into
That is, the area of the unit region may be increased. The controller 13 discriminates the unit area to which the current position of the self indicated by the current latitude data and longitude data belongs, drives the CD-ROM drive 31, and drives the CD-RO.
When reading map data M from M, to output a high data H _D of the unit area. Specifically, if it is assumed that the unit area A ₁₁ belongs to the current position of the vehicle indicated by the current latitude data and longitude data, the altitude data H _D11 is output. If the GPS receiver 11 can only perform two-dimensional positioning, the current position data output unit 32 will use the CD-RO.
And it outputs the latitude data and longitude data is output by the altitude data H _D and GPS receiver 11 is output by the M drive 31 as current position data D _POS.

Next, the data structure in the CD-ROM will be described with reference to FIG. CD-ROM map data in the M, the map mesh data storage unit 50 Figure leaves data are stored for outputting altitude data H _D is provided. The map leaf data is composed of drawing data for displaying a map other than roads and road data for drawing a road on a map and performing map matching. The drawing data storage unit 52 and the road data storage unit 53. Stored in each. Further, the drawing leaf data storage unit 50 includes a drawing leaf header 51 that stores data storage addresses of drawing data and road data.

The road data storage unit 53 shows the altitude table 55 for storing the altitude data H _{D1 to} H _Dn corresponding to the divided unit areas and the connecting points of roads such as intersections for drawing roads on the map. node and the node-link information table 56 for storing the link data indicating a line segment (a road) connecting the data and the node, a road header 54 as an address table for accessing elevation data H _D, node data and link data , And are configured.

Here, the configuration of the GPS receiver will be described in detail with reference to FIG. GPS receiver 11
The GPS antenna 11A is connected to the GPS receiving unit 40 via the preamplifier 31 and the bandpass filter 32, and outputs a reference frequency signal which is a timing control signal for the entire device, and a clock signal based on the reference frequency signal. A clock oscillating circuit 36, a signal processing unit 37 that performs various signal processes using a clock signal as an operation timing signal, and an arithmetic unit 20 that generates and outputs GPS data D _G based on the output signal of the signal processing unit 37. , And are configured. The GPS receiving unit 40 produces a signal having the same pattern as the data concerning the signal carrier of the GPS satellite, the position of the GPS satellite and the state of the clock in the GPS satellite based on the reference frequency signal, and a frequency synthesizing circuit 41.
A code generation circuit 42 that generates and outputs a code signal having the same pattern as the distance measurement signal from the GPS satellite based on the clock signal, and a clock in the GPS satellite based on the output signals of the frequency synthesis circuit 41 and the code generation circuit 42. And GPS
Data and carrier wave detector 43 for correlation detection of data and carrier wave relating to satellite orbit, and code lock detector 44 for correlation detection of distance measurement signal by code signal are provided.

Next, the detailed operation of the GPS navigation device will be described with reference to the operation flowchart of FIG.
First, the current position data output unit 15 includes the GPS receiver 11
Determines whether three-dimensional positioning is possible (step S
1).

When three-dimensional positioning is possible, that is, when radio waves can be received from four GPS satellites, G
The PS receiver 11 calculates the current position from the received radio waves (step S2) and outputs the latitude data X ₁ , the longitude data Y ₁ , and the altitude data Z ₁ to the current position data output unit 15 as GPS positioning data D _G. .. The current position data output unit 15 outputs the latitude data X ₁ , the longitude data Y ₁ , and the altitude data Z ₁ as the current position data D _POS (step S3). As a result, the controller 13 performs map matching with the map data M and outputs display data D _D for displaying the vehicle position on the map to the display (step S8), and the display 16 displays the vehicle's position on the map. The current position is displayed (step S9).

When the three-dimensional positioning is not possible in the determination of step S1, the current position data output unit 15 determines whether the GPS receiver 11 is capable of the two-dimensional positioning (step S4).

If two-dimensional positioning is possible, that is, if radio waves can be received from three GPS satellites, the GPS receiver 11 calculates the current position from those received radio waves (step S6). , Latitude data X ₂ and longitude data Y ₂ are output to the current position data output unit 15 as GPS positioning data D _G.

On the other hand, the controller 13 determines the unit area to which its own current position indicated by the current latitude data and longitude data belongs, drives the CD-ROM drive 31, and from the CD-ROM 15 the unit area reading the altitude data H _D (step S5). Current position data output unit 15, the latitude data X _2, and outputs the longitude data Y ₂ and altitude data H _D as current position data D _POS (step S7). As a result, the controller 13 performs map matching with the map data M and outputs display data D _D for displaying the vehicle position on the map to the display (step S8), and the display 16 displays the vehicle on the map. The current position of is displayed (step S9).

If the two-dimensional positioning is not possible in the determination of step S4, the current position data output unit 15 does not output the current position data D _POS and ends the process (step S4).
8).

As described above, the GPS receiver 11
Even if but which can not be only two-dimensional positioning by using the altitude data H _D, it is possible to obtain an accurate current position, it is possible to perform accurate navigation.

In the above embodiment, the navigation is performed using only the altitude data of the unit area to which the current position of the user belongs, but the unit area to which the current position of the user belongs and the unit areas adjacent to each other in the moving direction of the user. It is also possible to use the altitude data of a plurality of unit areas to obtain the altitude data by calculation. For the calculation in this case, a method such as simple averaging can be considered.

[0028]

According to the present invention, even when the GPS positioning means can perform only two-dimensional positioning, it is possible to obtain correct altitude data by using the altitude data stored for each unit area, and always obtain the correct current position. You can get location data,
Accurate navigation can be performed. Further, since the altitude data is stored for each unit area, it is possible to reduce the storage capacity as compared with the case where the altitude information is superposed on the road data, etc.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of an embodiment.

FIG. 2 is a diagram illustrating a storage state of altitude data.

FIG. 3 is an explanatory diagram of a data storage state of a CD-ROM.

FIG. 4 is a basic configuration diagram of a GPS receiver.

FIG. 5 is an operation flowchart of the embodiment.

FIG. 6 is a conventional operation flowchart.

[Explanation of symbols]

10 ... navigation system 11 ... GPS receiver 11A ... GPS antenna 12 ... current position data output unit 13 ... controller 14 ... CD-ROM 15 ... CD -ROM drive 16 ... display D _POS ... current position data H _D ... advanced data D _G ... GPS positioning data _D D ... display data M ... map data

Claims (1)

Claim: What is claimed is: 1. A GPS positioning means for receiving positioning radio waves from a GPS satellite, positioning the current position of the moving body, and outputting GPS positioning data. When the area of the range is divided into a plurality of unit areas and altitude data storage means for storing altitude data representing the actual altitude of the unit area, and the GPS positioning means performing two-dimensional positioning,
Based on the GPS positioning data, the unit area to which the current position of the moving body belongs is discriminated, the altitude data corresponding to the unit area is read from the altitude data storage unit, and the altitude data and the GPS positioning data are obtained. A current position calculation means for calculating and outputting current position data based on the current position data, and a GPS positioning device.