Positioning satellite selection device, positioning information transmitting device, and positioning system

Patent metadata

Field	Value
Publication number	US-11237275-B2
Application number	US-201515758102-A
Country	US
Kind code	B2
Filing date	Sep 17, 2015
Priority date	Sep 17, 2015
Publication date	Feb 1, 2022
Grant date	Feb 1, 2022

Abstract

A positioning satellite selection device that obtains a selection combination of positioning satellites used for positioning of a positioning target, and includes: a positioning data acquisition unit that acquires positioning data or navigation information, a range observation value, and an error correction value of this range observation value of a positioning satellite; a satellite position calculator that calculates a satellite position of the positioning satellite from the navigation information; a quality evaluation unit that evaluates quality of the positioning data; a shortest time designation unit that sets a shortest selection time during which the positioning satellite is selected to a larger value as poorer the quality; a plan creator that obtains the selection combination by selecting a positioning satellite conditioned on selecting for longer than the shortest selection time; and a plan storage that stores a plan of the selection combination of positioning satellites.

First claim

The invention claimed is:

1. A positioning system comprising:
a positioning information transmitting device comprising:
one or more computation processors configured to operate as:
a positioning data acquisition unit to acquire positioning data from a reference station which acquires from a plurality of positioning satellites the positioning data including respective range observation values and navigation information of each respective positioning satellite;
a satellite position calculation unit to calculate respective satellite positions at each time of the respective positioning satellites from the navigation information included in the positioning data;
a correction data generation unit to generate correction data for correcting an error included in the positioning data of the positioning satellites;
a quality evaluation unit to obtain a quality evaluation value by evaluating quality of the correction data;
a shortest time designation unit to set a shortest selection time which is a shortest time during which the positioning satellites are selected consecutively in time to a larger value as the quality evaluation value is poorer;
a plan creation unit to allocate a minimum number of positioning satellites for a selection combination of the positioning satellites, and to obtain the selection combination at each time of the positioning satellites to be used for positioning on conditions (1) and (2) of selecting for longer than the shortest selection time of the positioning satellite, by using, as an evaluation criterion, a precision degradation index obtained from a geometric arrangement in the sky at each time calculated from the satellite positions of the minimum number of the positioning satellites, (1) select and add an unselected positioning satellite that will best enhance the precision degradation index to the selection combination a time at which a number of selected satellites is less than an upper limit and the precision degradation index is poorest, and (2) if the unselected positioning satellite is determined by the positioning data acquisition unit to be visible at one of neighboring times before and after the time, further select the unselected positioning satellite for longer than the shortest selection time to be part of the selection combination; and
a correction data output unit to output the positioning satellites included in the selection combination at each time and the correction data for these positioning satellites;

the positioning information transmitting device outputting the positioning satellites included in the selection combination at each time of the positioning satellites and correction data for correcting an error included in the positioning data of the positioning satellites; and
a positioning terminal including a correction data acquisition unit to acquire from the positioning information transmitting device the positioning satellites included in a selection combination at each time of the positioning satellites, and correction data for correcting an error included in positioning data of these positioning satellites; a terminal positioning data acquisition unit to acquire positioning data including range observation values of the positioning satellites in the selection combination at each time; and a positioning computation unit to calculate a position at each time by using corrected range observation values obtained by correcting the range observation values of the positioning satellites with the correction data of the positioning satellites acquired by the correction data acquisition unit.

2. The positioning system according to claim 1 ,
wherein the plan creation unit selects the unselected positioning satellite further on condition (3) for which an interval of time from a latest time to an earliest time to which the unselected positioning satellite has already been allocated is shorter than the shortest selection time, and adds the unselected positioning satellite to a time at the interval of time.

3. The positioning system according to claim 1 ,
wherein the quality evaluation unit obtains the quality evaluation value by using one of an observation residual when the position is calculated using an observation value of the unselected positioning satellite, ranging precision information of the positioning satellites, and a standard deviation of differences in error correction values of the positioning satellites in each epoch, and
wherein the shortest time designation unit sets the shortest selection time to a value obtained based on a proportionality coefficient obtained from an error level target value and a sampling interval.

4. The positioning system according to claim 3 ,
wherein the proportionality coefficient of the shortest time designation unit is a value obtained by dividing the sampling interval by a square of the error level target value.

5. The positioning system according to claim 1 ,
wherein the plan creation unit selects as the minimum number of positioning satellites four or more visible positioning satellites sequentially from a satellite with a highest elevation angle, and generates an initial selection combination list of the four or more visible positioning satellites.

6. The positioning system according to claim 1 ,
wherein the plan creation unit is executed as a thread process, and starts the process a predetermine time before a plan end time of an existing plan.

7. The positioning system according to claim 1 ,
wherein the correction data output unit outputs the correction data to a positioning terminal via a multifunctional positioning satellite.

8. A positioning system comprising:
a positioning information transmitting device comprising:
one or more computation processors configured to operate as:
a positioning data acquisition unit to acquire positioning data from a reference station which acquires from a plurality of positioning satellites the positioning data including respective range observation values and navigation information of each respective positioning satellite;
a satellite position calculation unit to calculate respective satellite positions at each time of the respective positioning satellites from the navigation information included in the positioning data;
a correction data generation unit to generate correction data for correcting an error included in the positioning data of the positioning satellites;
a quality evaluation unit to obtain a quality evaluation value by evaluating quality of the correction data;
a shortest time designation unit to set a shortest selection time which is a shortest time during which the positioning satellites are selected consecutively in time to a larger value as the quality evaluation value is poorer;
a plan creation unit to allocate a minimum number of positioning satellites for a selection combination of the positioning satellites, and to obtain the selection combination at each time of the positioning satellites on a condition of selecting for longer than the shortest selection time by using, as an evaluation criterion, a precision degradation index obtained from a geometric arrangement in the sky at each time calculated from the satellite positions of the minimum number of the positioning satellites;
a plan modification unit to delete a previously selected positioning satellite from the selection combination based on the quality evaluation value, or add an unselected positioning satellite which is determined by the positioning data acquisition unit to be visible to the selection combination based on the precision degradation index; and
a correction data output unit to output the positioning satellites included in the selection combination at each time and the correction data for these positioning satellites;
the po

Assignees

• Mitsubishi Electric Corp

Inventors

• Sato Yuki
• Miya Masakazu

Classifications

• G01S19/071 Primary

  DGPS corrections · CPC title

• G01S19/28 Primary

  Satellite selection · CPC title

• G01S19/08

  providing integrity information, e.g. health of satellites or quality of ephemeris data · CPC title