JP2860621B2 - GPS positioning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a GPS (Global Posit
ioning System).

[0002]

2. Description of the Related Art A GPS positioning device receives radio waves from a plurality of artificial satellites (GPS satellites) belonging to the global positioning system and measures the position of the device.
It has begun to be widely used for checking the current position of various moving objects such as ships, aircraft, and automobiles, and has been found to be portable.

FIG. 6 is a block diagram of a conventional portable GPS positioning device. This GPS positioning device has a planar antenna 1 for receiving radio waves. G received by the planar antenna 1
The radio wave from the PS satellite is converted into a predetermined electric signal by the receiving unit 1.
Given to. The receiving unit 2 demodulates the supplied electric signal so that subsequent data processing can be performed and supplies the demodulated electric signal to the data processing unit 3. The data processing unit 3 measures the position of the positioning device using the given data.

On the other hand, a map data storage section 4 stores a map of Japan or the world as digital data and stores the map data desired by the user to a display processing section 5. The display processing unit 5 converts the given map data into, for example, L
The data is displayed on a CD, and the positioning data provided from the data processing unit 3 is displayed on the map. Therefore, the user can grasp the current location only by looking at the display screen of the display processing unit 5.

[0005]

In order to determine the current position using such a GPS positioning device,
There is a need to receive radio waves from at least three or more GPS satellites. However, in reality, it is not always possible to receive radio waves from three or more GPS satellites.
One or two objects obstructed by surrounding objects, buildings, etc.
In many cases, radio waves can be received only from GPS satellites.

[0006] Under such poor reception conditions, the conventional GPS positioning device has a problem that the current position cannot be determined. This problem has been a major obstacle in using GPS positioning devices, especially in urban areas where high-rise buildings are dense. With this, the user was forced to take inefficient measures such as searching for a wide place on an unfamiliar land without giving any guidelines, or climbing the rooftop of a building, and felt very inconvenient.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a GPS positioning device capable of continuing to determine the current position without interruption even when the reception condition of radio waves from GPS satellites deteriorates. With the goal.

[0008] A GPS positioning device according to the present invention is a GPS positioning device.
Communication between the means for receiving radio waves from satellites and the
Means for determining whether or not normal positioning is possible; means for normal positioning of the own position using the received radio wave when the radio wave reception state is normal positioning; and means for normal positioning when the radio wave reception state is not possible. Means for measuring the Doppler frequency of radio waves from one or two GPS satellites having good reception conditions, means for obtaining a moving velocity vector of itself using the measured Doppler frequency, and Means for estimating its own position.

[0009]

When the reception state of the radio wave is normal positioning, the own position is normally positioned using the reception radio wave. When the reception state of the radio wave becomes a state where positioning is normally impossible, the own moving velocity vector is obtained using the Doppler frequency of the radio wave from the GPS satellite having a good reception state. Since the position at the end of the normal positioning has been determined, its own position is estimated from the moving speed vector and the elapsed time after that point. When the reception status of the radio wave returns to the state where normal positioning is possible,
The self-position is usually located again using the received radio wave. Thus, even when the reception condition of the radio wave from the GPS satellites deteriorates, the current position can be determined without interruption.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external view of a portable GPS positioning device showing one embodiment of the present invention, FIG. 2 is a block diagram showing a schematic configuration of the GPS positioning device, and FIG. 3 is a flowchart showing an operation of the GPS positioning device.

[0011] As shown in FIG.
An external antenna 11 may be used, having an antenna 10 provided on the main surface of the device with a planar spread. An LCD display 61 and a keyboard 31 are further provided on the main front.

The antenna 10 receives radio waves from GPS satellites and converts them into electric signals. The electric signal is provided to the receiving unit 20, as shown in FIG. The receiving unit 20
The applied electric signal is demodulated into a digital signal and supplied to the data processing unit 30. The data processing unit 30 includes the direction sensor 4
0, it is connected to the map data storage unit 50 and the display processing unit 60.

The azimuth sensor 40 is a flux gate sensor composed of a ring-shaped core provided with a toroidal winding and a sense winding for detecting a magnetic flux leaking therefrom, and provides azimuth information to the data processing unit 30. The traveling direction (arrow) of the GPS positioning device is determined as shown in FIG. 1, and the traveling direction with respect to the azimuth becomes clear from the azimuth information given to the data processing unit 30.

The map data storage unit 50 stores a map of Japan or the world as digital data. The display processing unit 60 displays the image data provided from the data processing unit 30 on a screen.

The data processing section 30 has a simple microcomputer function, and processes data supplied from the receiving section 20 and the direction sensor 40 in accordance with a predetermined program stored in a memory (not shown). Further, the map data storage unit 50 is accessed as needed to read a map of a required area, and performs data processing according to a predetermined program process. Then, the processed data is provided to the display processing unit 60 as image data.

The LCD display 61 shown in FIG. The keyboard 31 is included in the data processing unit 30 and inputs a required signal by operating the keyboard 31. The contents of the display screen of the LCD display 61 will be described later.

Next, the operation of the GPS positioning device will be described with reference to the processing flow of FIG.

The GPS positioning device is assumed to be carried by a pedestrian for the time being. However, when the GPS positioning device is mounted on a car and used as a car navigation system by using the external antenna 11 as the antenna 10. May be assumed. Car navigation is easier to use because the traveling direction is determined.

The locator presses the ON / OFF key 31a on the keyboard 31 of the portable GPS positioning device, turns on the power, and starts the device. With this activation, the data processing unit 30 starts the processing shown in FIG.

In the process of step ST1, the data processing unit 30 determines whether almanac data (the number of currently received satellites, the currently received satellite number, the health status of all satellites at the present time, etc.) is stored in the internal memory. The determination is made by accessing the internal memory. If the almanac data is stored in the internal memory, the process branches to step ST3 and the following steps. If the almanac data is not stored in the internal memory, the process proceeds to the next step ST2.

In the process of step ST2, the data processing section 30 obtains almanac data. That is,
The data processing unit 30 obtains the satellite radio wave received via the antenna 10 via the receiving unit 20 and converts it into almanac data according to a known predetermined program process.
Temporarily store in internal memory. When the almanac data is stored in the internal memory, the data processing unit 30 proceeds to the next step ST3.

In the process of step ST3, in accordance with the almanac data stored in the internal memory, the locator operates the alphabet keys on the keyboard 31 to roughly input the current position. Thereby, the data processing unit 30 can roughly know the current position of the pedestrian.

Next, the data processing unit 30 proceeds to step ST4.
Thereafter, it is determined whether or not normal positioning is possible. That is, it is determined whether or not radio waves from at least three GPS satellites can be received in good condition. Specifically, based on almanac data obtained in advance by a known technique, G
DOP (Geometric Dilution Of Precison) data is calculated, and it is determined whether or not the current position can be determined (whether normal positioning is possible) based on whether or not the calculated value exceeds a certain threshold value. If the normal positioning is possible, the process shifts to the normal positioning mode of step ST5.

In the process of step ST5, a positioning operation is performed based on the received radio waves from at least three GPS satellites by a well-known technique, and positioning data for determining the current position is calculated. The process proceeds to ST6.

In the process of step ST6, the data processing unit 30 accesses the map data storage unit 50 based on the rough position data input in the process of step ST3, and reads out the map data from the map data storage unit 50. . Then, image data is created by, for example, superimposing the positioning data obtained by the positioning calculation and the read map data. The created image data is given to the display processing unit 60, and the display processing unit 60 displays the image data on the LCD display 61 as an image. As a result, the current position of the locator is displayed superimposed on the map. The current position of the positioner displayed on the LCD display 61 is indicated by 61a.

If it is determined in step ST4 that the normal positioning is impossible, that is, if one or more GPS satellites capable of receiving radio waves satisfactorily due to a radio wave obstruction of a surrounding building or the like.
If the number is two or two, the data processing unit 30
The supplementary positioning mode after T7 is executed.

In the process of step ST7, the moving speed vector of the positioner (the GPS positioning device) is obtained. Figure 4 shows the process for finding the speed vector of the locator.
It will be described with reference to to 5. GP that can receive radio waves well
Here, it is assumed that there is one S satellite.

FIG. 4 is a coordinate diagram three-dimensionally showing a positional relationship between a GPS satellite capable of receiving radio waves well and a positioner.
(X ₀ y ₀ z ₀ ) indicates the position of a GPS satellite that can receive radio waves favorably, and is known from radio wave information from the GPS satellites. (A ₀ b ₀ c ₀ ) represents the position of the locator, which is also known by using, for example, the position of the locator finally obtained in the normal positioning mode. Also, v is the moving velocity vector of the GPS satellites _{(x 0 y 0 z 0)} , u represents a moving velocity vector of the positioning's _{(a 0 b 0 c 0)} . The moving speed vector v of the satellite is known from radio wave information from the satellite. The moving speed vector u of the positioner is a vector to be obtained from now.

[0029] The GPS satellite (x ₀ y ₀ z ₀₎ and positioning person (a
₀ b ₀ c ₀ ), the component of the satellite's moving speed vector v on a straight line connecting the two is assumed to be v ′, and the positioning person's moving speed vector u
Is u ′. Further, the frequency of the radio wave from the satellite is f, and the frequency when the locator receives the radio wave is f '. The relationship of Equation 1 is established between these by the Doppler effect.

[0030]

F / f '= (cu') / (cv ') where c: speed of light

Therefore, the locator measures f ', that is, the Doppler frequency of the radio wave from the satellite, and the component u' of the locator's moving speed vector u is obtained from the component v 'of the moving speed vector v of the satellite. , The moving speed vector u of the positioner is obtained from the traveling direction of the positioner. That is, if the component v 'of the moving speed vector v of the satellite is obtained, the component u' of the moving speed vector u of the positioner is obtained from the Doppler frequency f 'of the radio wave, and furthermore, the moving speed vector u of the positioner is obtained. is there.

First, a method of obtaining the component v 'of the moving speed vector v of the satellite will be described with reference to FIG.

[0033] Figure 5 is a coordinate diagram showing around the two-dimensionally GPS satellites _{(x 0 y 0 z 0)} . GPS satellite (x ₀ y
₀ z ₀₎ and positioning's (a ₀ b ₀ c ₀ r between), the a, moving velocity vector v and positioning's satellite between moving velocity vector v of the satellite and its components v '(a ₀ b ₀ If b is set between c ₀ ), Equation 2 is established.

[0034]

## EQU2 ## v ² = a ² + v ′ ² b ² = a ² + (r−v ′) ²

In equation (2), when a is deleted, equation (3) is obtained, from which the component v 'of the moving velocity vector v of the satellite is represented by equation (4).

[0036]

## EQU3 ## b ² = v ² −v ′ ² + (rv ′) ² = v ² + r ² −2rv ′

[0037]

## EQU4 ## v '= (v ² + r ² -b ² ) / 2r

Here, the moving speed vector v of the satellite is represented by its position per unit time (x ₁ y ₁ z ₁ ) and is known. In addition, each position (x ₀₎ of the GPS satellite and the positioner
Since both y ₀ z ₀ ) (a ₀ b ₀ c ₀ ) are known, b and r are also known. Therefore, the component v 'of the moving speed vector v of the satellite is obtained by Expression 4.

When the component v 'of the moving velocity vector v of the satellite is obtained, the Doppler frequency f' of the radio wave from the GPS satellite is obtained.
A component u ′ of the locator's moving speed vector u is obtained from (Equation 1), and by taking into account the traveling direction of the locator, that is, the angle between the locator's moving speed vector u and its component u ′, The moving speed vector u of the positioner is obtained.

[0040] Therefore now Description bright-a method of determining the moving speed Bekutsutoru u positioning's from a component u 'of the moving velocity vector u positioning's.

Normally obtained (immediately before) in the positioning mode
Geographic location of the measurer and the direction of the measurer's travel
Azimuth angle is also known, and for Doppler frequency measurement
The geographical position of the received GPS satellites is also
It is known from wave information.

Therefore, the position of the measurer or the position from the satellite
Can easily calculate the geographic elevation angle seen by the measurer.
You.

From this, it is finally (just before) that the measurer
Vector multiply the moving angle vector u 'by the angle of elevation and the angle of elevation
Thus , the moving speed vector u of the positioner can be calculated.

Since the locator usually exists on the geographical ground plane, calculation on the horizontal plane does not pose any particular problem.

[0045]

[0046]

[0047]

[0048]

When the moving speed vector u of the positioner is obtained in the process of step ST7, the data processing unit 30 executes the process of step ST8.

In the processing of step ST8, the current position 61a of the positioner obtained in the processing of step ST6
, The current position of the positioner is estimated from the moving speed vector u of the positioner and the elapsed time obtained in the process of step ST7 and displayed on the LCD display 61. The estimated position displayed on the LCD display 61 is shown by 61b in FIG.

While the state of reception of radio waves from the GPS satellites is poor and normal positioning is impossible, the processing of steps ST7 and ST8 is repeated starting from the current position of the positioner estimated in the previous processing as a starting point. Are estimated one after another and displayed on the LCD display 61. At this time, if the movement locus of the positioning position or the positioning position when the positioning person moves is left long on the LCD display 61, the positioning person can always check his own position and route,
Highly reliable and usable navigation information can be obtained.

Thus, even when the reception condition of the radio wave from the GPS satellite is poor, the current position can be determined without interruption.

When the reception condition of the radio waves from the GPS satellites is improved and the radio waves can be received from at least three GPS satellites in good condition, the data processing unit 30 proceeds to step S.
The processing of T5 and T6, that is, the normal positioning mode is executed.

[0054]

As described above, in the case of the GPS positioning apparatus according to the present invention, when the reception state of the radio wave becomes a state where the positioning cannot be normally performed, the GPS positioning apparatus uses the Doppler frequency of the radio wave from the GPS satellite having a good reception state to perform its own operation. Is obtained and the current position of the vehicle is estimated, so that the current position can be determined without interruption even when the reception condition of the radio wave from the GPS satellites deteriorates. Therefore, the GPS positioning device can be used without trouble even in an urban area where high-rise buildings are densely packed. Accordingly, the user does not need to take inefficient measures such as searching for a wide place on an unfamiliar land or climbing the roof of a building, and the usability of the GPS positioning device is significantly improved.

[Brief description of the drawings]

FIG. 1 is an external view of a portable GPS positioning device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of the GPS positioning device.

FIG. 3 is a flowchart showing an operation of the GPS positioning device.

FIG. 4 is a coordinate diagram showing a positional relationship between a GPS satellite and a positioner.

FIG. 5 is a coordinate diagram for explaining a method for obtaining a moving speed vector component of a GPS satellite.

FIG. 6 shows a schematic configuration of a conventional portable GPS positioning device.
It is a block diagram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Antenna 20 Receiving part 30 Data processing part 31 Keyboard 40 Direction sensor 50 Map data storage part 60 Display processing part 61 LCD display

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01S 5/00-5/14

Claims (1)

(57) [Claims] 1. A means for receiving a radio wave from a GPS satellite, a means for determining whether or not the radio wave reception state is normal positioning possible, and using the received radio wave when the radio wave reception state is normal positioning possible. means for normally positioning the own position, when the reception state of radio wave is a normal positioning impossible reception condition is good 1
Means for measuring the Doppler frequency of radio waves from one or two GPS satellites, means for calculating the own moving speed vector using the measured Doppler frequency, and estimating the own position based on the obtained moving speed vector And a GPS positioning device.