Positioning system

• US 6,917,330 B2
• Filed: 10/29/2001
• Issued: 07/12/2005
• Est. Priority Date: 07/09/2001
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Ohmura, Yuji, Ohke, Tadanobu, Saito, Masayuki
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US09/984,136
• Publication Number:
  US 20030008666A1
• Time in Patent Office: 1,352 Days
• Field of Search: 342/357.02, 342/357.06, 342/357.15
• US Class Current: 342/357.29
• CPC Class Codes: G01S 19/28 Satellite selection
• CPC Class Codes: G01S 19/426 by combining or switching between position solutions or signals derived from different modes of operation in a single system

Abstract

In order to solve a conventional problem that precision deterioration that cannot be determined by only a DOP, a positioning system is provided which comprises: a receiver for receiving signals from a plurality of positioning satellites to output data received from satellites; a satellite selector for selecting a plurality of combinations of positioning satellites to be objects of positioning calculation based on the data received from satellites to output satellite combination data; a positioning calculator for performing positioning calculation based on the data received from satellites and the satellite combination data to output positioning results thereof; a velocity detector for detecting a velocity of the positioning system to output velocity data; and a positioning output determining unit for selecting a positioning result closest to a predicted position out of the positioning results to output the positioning result as a positioning output.

Claims

1. A positioning system comprising:

a receiver for receiving signals from a plurality of positioning satellites to output data received from the positioning satellites;

a satellite selector for selecting a plurality of combinations of positioning satellites to be objects of positioning calculation based on the data received from the positioning satellites to output satellite combination data;

a positioning calculator for performing positioning calculations based on the data received from the positioning satellites and the satellite combination data to output positioning results thereof; and

a positioning output determining unit for selecting a positioning result from among the positioning results that is closest to a predicted position to output the selected positioning result as a positioning output.

2. A positioning system according to claim 1,

wherein said satellite selector includes:

a satellite combination generator for generating second satellite combination data that combines the data received from satellites;

a DOP calculator for calculating a DOP using the second satellite combination data based on the data received from the positioning satellites to output a DOP value;

an aligning selector for aligning the plurality of DOP values to select a subset according to sizes of the DOP values; and

a combination data selecting and outputting unit for selecting a subset of outputs of said satellite combination generator using outputs of said aligning selector to output the satellite combination data.

3. A positioning system according to claim 1,

wherein said positioning output determining unit includes:

a positioning output selector for selecting a positioning result closest to a predicted position using the positioning results and a difference between the positioning results and the predicted position to output the positioning result as a positioning output;

a trajectory predictor for predicting a trajectory of said positioning system using the positioning output to output the predicted position; and

a difference calculation unit for calculating a difference between the positioning results and the predicted position.

4. A positioning system according to claim 3,

wherein said trajectory predictor includes:

a first coordinate converter for converting a coordinate system of the positioning output to a first coordinate system expressed by a latitude, a longitude and an altitude;

a trajectory calculator for performing trajectory predicting calculation using a predetermined model based on the first coordinate system and outputting a predicted value of a second coordinate system expressed by a latitude, a longitude and an altitude; and

a second coordinate converter for converting the predicted value of the second coordinate system to the coordinate system of the predicted position.

5. A positioning system according to claim 4,

wherein said trajectory calculator performs trajectory predicting calculation on an assumption that said positioning system is taking a uniform acceleration motion.

6. A positioning system according to claim 1,

wherein said positioning output determining unit includes:

a selector for selecting a plurality of positioning results close to the predicted position using the positioning result and a difference between the positioning result and the predicted position to output them as selected outputs;

a positioning output calculator for calculating a position using a plurality of selected outputs of said selector to output it as a positioning output;

a trajectory predictor for predicting a trajectory of said positioning system using the positioning output to output the predicted position; and

a difference calculation unit for calculating a difference between the positioning result and the predicted position.

7. A positioning system according to claim 3,

wherein said trajectory predictor includes:

a first coordinate converter for converting a coordinate system of the positioning output to a first coordinate system expressed by a latitude, a longitude and an altitude;

a trajectory calculator for performing trajectory predicting calculation using a predetermined model based on the first coordinate system and outputting a predicted value of a second coordinate system expressed by a latitude, a longitude and an altitude, and at the same time outputting a predicted value of coordinate system fluctuation for predicting that a trajectory of said positioning system fluctuates from a coordinate system currently used;

a second coordinate converter for converting the predicted value of the second coordinate system to the coordinate system of the predicted position; and

a coordinate system updating unit for updating a coordinate system to be used in trajectory predicting calculation based on the predicted value of coordinate system fluctuation.

8. A positioning system according to claim 7, wherein said trajectory calculator performs trajectory predicting calculation on an assumption that said positioning system is moving on a predetermined straight line.

9. A positioning system according to claim 7,

wherein said coordinate system updating unit includes:

a generator of coordinate system updating conversion matrix for calculating an angle deviation between each coordinate axis and predicted trajectory using the predicted value of coordinate system fluctuation to generate a coordinate system updating conversion matrix that rotates a coordinate conversion matrix in the direction for compensating for the angle deviation; and

a conversion matrix updating unit for applying said coordinate system updating conversion matrix to a present conversion matrix to update the conversion matrix.

19. A positioning system according to claim 6,

wherein said trajectory predictor includes:

a first coordinate converter for converting a coordinate system of the positioning output to a first coordinate system expressed by a latitude, a longitude and an altitude;

a trajectory calculator for performing trajectory predicting calculation using a predetermined model based on the first coordinate system and outputting a predicted value of a second coordinate system expressed by a latitude, a longitude and an altitude, and at the same time outputting a predicted value of coordinate system fluctuation for predicting that a trajectory of said positioning system fluctuates from a coordinate system currently used;

a second coordinate converter for converting the predicted value of the second coordinate system to the coordinate system of the predicted position; and

a coordinate system updating unit for updating a coordinate system to be used in trajectory predicting calculation based on the predicted value of coordinate system fluctuation.

10. A positioning system comprising:

a receiver for receiving signals from a plurality of positioning satellites to output data received from positioning satellites;

a satellite selector for selecting a plurality of combinations of the positioning satellites to be objects of positioning calculation based on the data received from the positioning satellites to output satellite combination data;

a positioning calculator for performing positioning calculations based on the data received from the positioning satellites and the satellite combination data to output positioning results thereof;

a velocity detector for detecting a velocity of said positioning system to output velocity data; and

a positioning output determining unit for selecting a positioning result from among the positioning results that is closest to a predicted position to output the selected positioning result as a positioning output,

wherein the predicted position is based on the velocity data.

11. A positioning system according to claim 10,

wherein said satellite selector includes:

a satellite combination generator for generating second satellite combination data that combines the data received from the positioning satellites;

a DOP calculator for calculating a DOP using the second satellite combination data based on the data received from the positioning satellites to output a DOP value;

an aligning selector for aligning the plurality of DOP values, thereby selecting a subset according to sizes of the values; and

a combination data selecting and outputting unit for selecting a subset of outputs of said satellite combination generator using outputs of said aligning selector to output the satellite combination data.

12. A positioning system according to claim 10,

wherein said positioning output determining unit includes:

a positioning output selector for selecting a positioning result closest to a predicted position using the positioning results and a difference between the positioning results and the predicted position to output the positioning result as a positioning output;

a trajectory predictor for predicting a trajectory of a positioning system using the positioning output and the velocity data to output the predicted position; and

a difference calculation unit for calculating a difference between the positioning results and the predicted position.

13. A positioning system according to claim 12,

wherein said trajectory predictor includes:

a first coordinate converter for converting a coordinate system of said positioning output to a first coordinate system expressed by a latitude, a longitude and an altitude;

a second coordinate converter for converting a coordinate system of the velocity data to a second coordinate system expressed by a latitude, a longitude and an altitude;

a trajectory calculator for performing trajectory predicting calculation using a predetermined model based on the first and second systems of coordinates and outputting a predicted valued of a third coordinate system expressed by a latitude, a longitude and an altitude; and

a third coordinate converter for converting the predicted value of the third coordinate system to the coordinate system of the predicted position.

14. A positioning system according to claim 13,

wherein said trajectory calculator performs the trajectory predicting calculation on an assumption that said positioning system is taking a uniform acceleration motion.

15. A positioning system according to claim 10,

wherein said positioning output determining unit includes:

a selector for selecting a plurality of positioning results close to the predicted position using the positioning result and a difference between the positioning result and a predicted position to output them as selected outputs;

a positioning output calculator for calculating a position using a plurality of selected outputs of said selector to output it as a positioning output;

a trajectory predictor for predicting a trajectory of said positioning system using the positioning output and the velocity data to output the predicted position; and

a difference calculation unit for calculating a difference between the positioning result and the predicted position.

16. A positioning system according to claim 12,

wherein said trajectory predictor includes:

a first coordinate converter for converting a coordinate system of the positioning output to a first coordinate system expressed by a latitude, a longitude and an altitude;

a second coordinate converter for converting a coordinate system of the velocity data to a second coordinate system expressed by a latitude, a longitude and an altitude;

a trajectory calculator for performing trajectory predicting calculation using a predetermined model based on the first and second systems of coordinates and outputting a predicted value of a third coordinate system expressed by a latitude, a longitude and an altitude, and at the same time outputting a predicted value of coordinate system fluctuation for predicting that a trajectory of said positioning system fluctuates from a coordinate system currently used;

a third coordinate converter for converting the predicted value of the third coordinate system to the coordinate system of the predicted position; and

a coordinate system updating unit for updating a coordinate system to be used in trajectory predicting calculation based on the predicted value of coordinate system fluctuation.

17. A positioning system according to claim 16,

wherein said trajectory calculator performs trajectory predicting calculation on an assumption that said positioning system is moving on a predetermined straight line.

18. A positioning system according to claim 16,

wherein said coordinate system updating unit includes:

a generator of coordinate system updating conversion matrix for calculating an angle deviation between each coordinate axis and a predicted trajectory using the predicted value of coordinate system fluctuation to generate a coordinate system updating conversion matrix that rotates a coordinate conversion matrix in a direction for compensating for the angle deviation; and

a conversion matrix updating unit for applying said coordinate system updating conversion matrix to a present conversion matrix to update the conversion matrix.

20. A positioning system according to claim 15,

wherein said trajectory predictor includes:

a first coordinate converter for converting a coordinate system of the positioning output to a first coordinate system expressed by a latitude, a longitude and an altitude;

a second coordinate converter for converting a coordinate system of the velocity data to a second coordinate system expressed by a latitude, a longitude and an altitude;

a trajectory calculator for performing trajectory predicting calculation using a predetermined model based on the first and second systems of coordinates and outputting a predicted value of a third coordinate system expressed by a latitude, a longitude and an altitude, and at the same time outputting a predicted value of coordinate system fluctuation for predicting that a trajectory of said positioning system fluctuates from a coordinate system currently used;

a third coordinate converter for converting the predicted value of the third coordinate system to the coordinate system of the predicted position; and

a coordinate system updating unit for updating a coordinate system to be used in trajectory predicting calculation based on the predicted value of coordinate system fluctuation.