JPH07280915A - Gps receiver - Google Patents

Abstract

PURPOSE:To obtain a GPS receiver whose positioning accuracy is enhanced by computing a horizontal position on the basis of a combination of satellites whose HDOP (accuracy drop rate in the determination of a position inside a horizontal plate) is small and computing an altitude on the basis of a combination of satellites whose VDOP (accuracy drop rate in the determination of a position in the up-and-down direction) is small. CONSTITUTION:Transmitted radio waves from a GPS satellite received by an antenna 11 are demodulated by a signal processing means 12, and navigation messages which have been demodulated, are stored in a navigation-message storage means 13. By using almanac information on the navigation messages, from a plurality of satellites, which are stored in the navigation-message storage means 13, the satellites which are suitable for the positioning of a horizontal position and the positioning of an altitude are selected respectively by an HDOP operation means 14 and a VDOP operation means 16. The horizontal position and the altitude are computed respectively by a horizontal-position operation means 15 and an altitude operation means 17 by using a selected result and ephemeris information on the navigation messages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a GPS (Global Positioning Sys) for use in a car navigation system or the like.
tem) regarding the receiver.

[0002]

2. Description of the Related Art FIG. 3 shows a schematic structure of a conventional GPS receiver. In FIG. 3, reference numeral 1 is an antenna for receiving radio waves from GPS satellites. 2 is signal processing means, 3
Is a navigation message storage means, 4 is a positioning satellite selection means, 5
Is a positioning calculation means.

The operation of the conventional GPS receiver configured as above will be described below. First, the antenna 1 receives radio waves from GPS satellites. Next, the contents received by the signal processing means 2 are demodulated, and the demodulated navigation messages of a plurality of satellites are stored in the navigation message storage means 3. Next, the positioning satellite selection means 4 uses the almanac information of the navigation message stored in the navigation message storage means 3 to perform HDOP (Horizontal dilution).
of precision: Calculate the accuracy decrease rate when determining the position in the horizontal plane), and select the satellite combination with the smallest HDOP value. Then, using the satellite selection result calculated by the positioning satellite selection means 4 and the ephemeris information of the navigation messages of the plurality of satellites stored by the navigation message storage means 3, the positioning calculation means 5 calculates the horizontal position / altitude.

As described above, in the conventional GPS receiver described above, the combination of satellites for positioning is determined by calculating HDOP.

[0005]

However, in the above-mentioned conventional GPS receiver, the positioning satellite selection means selects a satellite only by the calculation result of HDOP, and thus there is a problem that the high-precision positioning accuracy is deteriorated.

[0006] The present invention solves such a conventional problem, and an object of the present invention is to provide an excellent GPS receiver capable of improving high-level positioning accuracy.

[0007]

In order to achieve the above-mentioned object, the present invention provides an HDOP calculating means and a VDOP (Vertical dilution of precision) calculating means as positioning satellite selecting means. Two sets are provided, and the combination of satellites for positioning calculation of the horizontal position and the combination of satellites for positioning calculation of the altitude are calculated independently, and the horizontal position and the altitude are calculated based on the selection result. It is designed to perform positioning.

[0008]

Therefore, according to the present invention, the horizontal position is calculated from the combination of GPS satellites having a small HDOP, and the VD is calculated.
By calculating the altitude from the combination of GPS satellites having a small OP, the positioning accuracy of the horizontal position and the altitude can be improved.

[0009]

【Example】

(Embodiment 1) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of the first embodiment of the present invention. In FIG. 1, 11 is an antenna for receiving radio waves from GPS satellites, 12 is a signal processing means for demodulating the received radio waves, and 13 is a navigation message storage means for storing the demodulated navigation messages of a plurality of satellites. 14
Is HDOP calculation means for calculating HDOP using the almanac information of navigation messages of a plurality of satellites stored in the navigation message storage means 13 and selecting a combination of satellites suitable for horizontal positioning, and 15 is HDO.
It is a horizontal position calculating means for calculating the horizontal position using the satellite selection result calculated by the P calculating means 14 and the ephemeris information of the navigation messages of a plurality of satellites stored by the navigation message storing means 13. Reference numeral 16 is a VDOP using the almanac information of navigation messages of a plurality of satellites stored by the navigation message storage means 13.
Is a VDOP calculation means for calculating a combination of satellites suitable for altitude positioning, and 17 is a VDOP calculation means 1
The altitude calculation means calculates the altitude using the satellite selection result calculated in 6 and the ephemeris information of the navigation messages of a plurality of satellites stored in the navigation message storage means 13.

Next, the operation of the first embodiment will be described. In the first embodiment, the radio wave from the GPS satellite received by the antenna 11 is demodulated by the signal processing means 12. The demodulated navigation message is stored in the navigation message storage means 13 for each satellite. Using the almanac information of the navigation message stored in the navigation message storage means 13, the HDOP calculation means 14 calculates the HDOP, and the satellite combination having the smallest HDOP value is selected. At the same time, using the almanac information of the navigation message stored in the navigation message storage means 13, the VDOP calculation means 16V is used.
The DOP is calculated, and the combination of satellites having the smallest VDOP value is selected. The horizontal position calculation unit 15 calculates the horizontal position using the combination result of satellites suitable for horizontal position measurement calculated by the HDOP calculation unit 14 and the ephemeris information of the navigation message stored in the navigation message storage unit 13. Further, the altitude calculation means 17 calculates the altitude using the combination result of the satellites suitable for altitude positioning calculated by the VDOP calculation means 16 and the ephemeris information of the navigation message stored in the navigation message storage means 13.

As described above, according to the first embodiment,
Since an optimal combination of satellites for positioning the horizontal position and altitude is selected for positioning calculation, there is an advantage that the positioning accuracy of the horizontal position and altitude can be improved.

(Second Embodiment) Next, a second embodiment of the present invention will be described. FIG. 2 shows the configuration of the second embodiment of the present invention. In FIG. 2, reference numeral 21 is an antenna for receiving radio waves from GPS satellites, 22 is a signal processing means for demodulating the received radio waves, and 23 is a navigation message storage means for storing the demodulated navigation messages of a plurality of satellites. Reference numeral 24 indicates H by using the almanac information of the navigation messages of a plurality of satellites stored by the navigation message storage means 23.
HDOP calculation means for calculating a DOP and selecting a combination of satellites suitable for horizontal positioning, 25 is HDOP for three satellites using almanac information of navigation messages of a plurality of satellites stored in the navigation message storage means 23. And a HDOP calculation means of three satellites for selecting a combination of three satellites suitable for horizontal positioning,
Is a selector that determines which of the two satellite selection results calculated by the HDOP calculating means 24 and the HDOP calculating means 25 of three satellites is used for horizontal position positioning. Reference numeral 27 is a VDOP calculation means for calculating a VDOP using the almanac information of the navigation messages of a plurality of satellites stored in the navigation message storage means 23 and selecting a combination of satellites suitable for altitude positioning.
Reference numeral 8 is an altitude calculation means for calculating the altitude using the satellite selection result calculated by the VDOP calculation means 27 and the ephemeris information of the navigation messages of a plurality of satellites stored by the navigation message storage means 23. Reference numeral 29 indicates the satellite selection result determined by the selector 26, the ephemeris information of the navigation messages of a plurality of satellites stored by the navigation message storage means 23, and the altitude calculated by the altitude calculation means 28 when positioning by three satellites. It is a horizontal position calculating means for calculating the horizontal position.

Next, the operation of the second embodiment will be described. In the second embodiment, the radio wave from the GPS satellite received by the antenna 21 is demodulated by the signal processing means 22. The demodulated navigation message is stored in the navigation message storage means 23 for each satellite. Using the almanac information of the navigation message stored in the navigation message storage means 23, HDOP calculation means 24 calculates HDOP and the satellite combination with the smallest HDOP value is selected. At the same time, using the almanac information of the navigation message stored in the navigation message storage means 23, the HDOP calculation means 25 of the three satellites calculates the HDOP of the three satellites to obtain the HDOP.
Select the combination of the three satellites with the smallest value of.
At the same time, the almanac information of the navigation message stored in the navigation message storage means 23 is used to perform VD
VDOP is calculated by the OP calculation means 27, and VDOP is calculated.
Select the satellite combination with the smallest value of. V
The satellite combination result calculated by the DOP calculation means 27 suitable for altitude positioning, and the navigation message storage means 2
The altitude calculation means 28 calculates the altitude using the ephemeris information of the navigation message stored in 3. Then, the HDOP calculated by the VDOP calculation means 24
And the HDOP calculated by the HDOP calculation means 25 of the three satellites are compared by the selector 26, and a combination of satellites having a smaller value of HDOP is determined as a combination of satellites suitable for horizontal position positioning. The combination result of the satellites suitable for horizontal position positioning determined by the selector 26, the ephemeris information of the navigation message stored in the navigation message storage means 23, and the altitude calculated by the altitude calculation means 28 when positioning with three satellites are performed. The horizontal calculation means 29 is used to calculate the horizontal position.

As described above, according to the second embodiment,
When the HDOP of 3 satellites is smaller than the HDOP of 4 satellites, the horizontal position of 3 satellites is obtained by using the accurate altitude information to obtain a more accurate horizontal position than the case of 4 satellites. It has the advantage that

[0015]

As is apparent from the above embodiment, the present invention provides HDOP calculation means and VDO as positioning satellite selection means.
Two P calculation means are provided to independently calculate a combination of satellites for horizontal positioning calculation and a combination of satellites for advanced positioning calculation, and the horizontal combination is calculated based on the selection result. Since the positioning of the position and the altitude is performed, the positioning accuracy of the horizontal position and the altitude can be improved.

The present invention also has an effect that an accurate horizontal position can be obtained by horizontal position positioning with three satellites smaller than HDOP of four satellites by utilizing the calculated altitude information for horizontal position positioning. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a GPS receiver according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a GPS receiver according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a conventional GPS receiver.

[Explanation of symbols]

 11 antenna 12 signal processing means 13 navigation message decoding means 14 HDOP calculation means 15 horizontal position calculation means 16 VDOP calculation means 17 altitude calculation means 21 antenna 22 signal processing means 23 navigation message decoding means 24 HDOP calculation means 25 3 satellite HDOP calculation means 26 selector 27 VDOP calculation means 28 altitude calculation means 29 horizontal position calculation means

Claims (3)

[Claims] 1. An HDOP computing means for calculating HDOP (rate of decrease in accuracy when determining a position in a horizontal plane) and selecting a combination of satellites having the smallest HDOP value, and V.
VDOP calculation means for calculating DOP (rate of accuracy decrease in position determination in the vertical direction) and selecting a combination of satellites having the smallest VDOP value, and horizontal position calculation for calculating the horizontal position based on the output of the HDOP calculation means. Position calculation means,
A GPS receiver provided with an altitude calculation means for calculating an altitude based on the output of the VDOP calculation means. 2. An antenna for receiving radio waves transmitted from GPS satellites, a signal processing means for demodulating the received contents, a navigation message storage means for storing the demodulated navigation messages of a plurality of satellites, and a navigation message storage means. By using the navigation message storage means and the HDOP calculation means for calculating the HDOP (the accuracy reduction rate when determining the position in the horizontal plane) using the almanac information of the navigation messages of the plurality of satellites, and selecting the satellite suitable for the horizontal positioning. Calculated by VDOP calculation means and HDOP calculation means for selecting a satellite suitable for altitude positioning by calculating VDOP (rate of accuracy decrease in vertical position determination) using the stored almanac information of navigation messages of a plurality of satellites Stored by the satellite selection results and navigation message storage means The horizontal position calculating means for calculating the horizontal position by using the ephemeris information of the navigation messages of the plurality of satellites, and the satellite selection result calculated by the VDOP calculating means and the navigation message of the plurality of satellites stored by the navigation message storage means. A GPS receiver comprising: an altitude calculation means for calculating altitude using ephemeris information, and calculating the horizontal position and altitude by an optimum combination of respective satellites. 3. An antenna for receiving radio waves transmitted from GPS satellites, a signal processing means for demodulating the received contents, a navigation message storage means for storing the demodulated navigation messages of a plurality of satellites, and a navigation message storage means. By using the navigation message storage means and the HDOP calculation means for calculating the HDOP (the accuracy reduction rate when determining the position in the horizontal plane) using the almanac information of the navigation messages of the plurality of satellites, and selecting the satellite suitable for the horizontal positioning. Calculated by VDOP calculation means and VDOP calculation means for calculating satellites suitable for altitude positioning by calculating VDOP (rate of accuracy decrease in vertical position determination) using the stored almanac information of navigation messages of a plurality of satellites Stored by the satellite selection results and navigation message storage means The altitude calculation means for calculating the altitude using the ephemeris information of the navigation messages of the plural satellites, and the almanac information of the navigation messages of the plural satellites stored by the navigation message storage means.
3 satellite HDOP calculation means for calculating HDOP in satellites and selecting 3 satellites suitable for horizontal positioning, satellite selection result calculated by VDOP calculation means and satellite selection result calculated by 3 satellite HDOP calculation means The altitude obtained by the selector that selects which of the satellite selection results to calculate the horizontal position by comparing the respective HDOP values, and the altitude calculation means that calculates the satellite selection result and the altitude selected by the selector And a horizontal position calculating means for calculating a horizontal position using the ephemeris information of navigation messages of a plurality of satellites stored by the information and navigation message storage means, which is suitable for advanced positioning when horizontal positioning is performed by three satellites. A GPS receiver characterized by calculating a horizontal position using altitude information calculated by a combination of satellites. Aircraft.