CROWDSOURCING ATMOSPHERIC CORRECTION DATA

• US 20190004180A1
• Filed: 06/29/2017
• Published: 01/03/2019
• Est. Priority Date: 06/29/2017
• Status: Active Grant

• Current Assignee: Novatel Incorporated (Hexagon AB)
• Original Assignee: Novatel Incorporated (Hexagon AB)
• Inventors: Jokinen, Altti
• Granted Patent: US 10,690,775 B2
• Time in Patent Office: Days
• CPC Class Codes: G01S 19/04 providing carrier phase data
• CPC Class Codes: G01S 19/072 Ionosphere corrections
• CPC Class Codes: G01S 19/44 Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method

Abstract

A system and method crowdsources atmospheric data from one or more rovers. The rovers calculate an estimated ionosphere delay value that indicates an adverse effect of ionospheric activity on signals received from the GNSS satellite. The values and identifiers may be transmitted to a server. The server utilizes the received information to generate an ionosphere map that reflects the magnitude of ionospheric delay at different locations. The ionosphere map is transmitted to one or more rovers. The rover determines if a pierce point associated with a selected GNSS satellite in view of the rover falls within the boundaries of the ionosphere map. If so, a corresponding ionosphere delay value is obtained utilizing the ionosphere map and then applied as a correction to account for ionospheric activity. In addition, the central server and/or rover may transmit the estimated ionosphere delay values and identifiers to other rovers.

Claims

1. A system, comprising:

a processor and a memory, the processor configured to;

receive, from at least one rover, one or more estimated ionosphere delay values where each estimated ionosphere delay value is calculated for a corresponding global navigation satellite systems (GNSS) satellite in view of the rover, and wherein the estimated ionosphere delay value indicates an adverse effect of ionospheric activity on satellite signals transmitted by the corresponding GNSS satellite,

receive, from the at least one rover, coordinates of one or more pierce points and coordinates of the rover, wherein the coordinates of each pierce point indicate an intersecting location of the satellite signals transmitted by the corresponding GNSS satellite and the ionosphere, and

generate an ionosphere map that reflects the ionospheric activity, wherein the ionosphere map is generated utilizing the one or more estimated ionosphere delay values, the coordinates of the one or more pierce points received from the at least one rover, and the coordinates of the rover received from the at least one rover.

2. The system of claim 1, wherein the processor is further configured to receive, from the at least one rover, an identifier that uniquely identifies the rover and an identifier that uniquely identifies the corresponding GNSS satellite.

3. The system of claim 2, wherein a table is stored in the memory, wherein an entry of the table is configured to store the estimated ionosphere delay value calculated for the corresponding GNSS satellite, the coordinates of the pierce point associated with the corresponding GNSS satellite, the identifier that uniquely identifies the rover, the coordinates of the rover, the identifier that uniquely identifies the corresponding GNSS satellite, a standard deviation of estimated ionosphere delay values, and a reference time at which the estimated ionosphere delay value was calculated.

4. The system of claim 1, wherein as the estimated ionosphere delay value increases, the processor is further configured to determine that the adverse effect of the ionospheric activity on the satellite signals is getting stronger.

5. The system of claim 1 wherein the processor is further configured to transmit the ionosphere map to one or more rovers, wherein each rover obtains a corresponding estimated ionosphere delay value as a correction for satellite range measurement utilizing the received ionosphere map.

6. The system of claim 5 wherein the corresponding estimated ionosphere delay value is obtained based on a rover pierce point falling within a particular cell of the ionosphere map.

7. The system of claim 1 wherein the one or more estimated ionosphere delay values are received in one or more broadcast messages.

8. A method comprising:

receiving, at a server having a processor and a memory, one or more estimated ionosphere delay values from at least one rover, wherein each estimated ionosphere delay value is calculated for a corresponding global navigation satellite systems (GNSS) satellite in view of the rover, and wherein the estimated ionosphere delay value indicates an adverse effect of ionospheric activity on satellite signals transmitted by the corresponding GNSS satellite;

receiving, at the server, coordinates of one or more pierce points and coordinates of the rover from the at least one rover, wherein the coordinates of each pierce point indicate an intersecting location of the satellite signals transmitted by the corresponding GNSS satellite and the ionosphere; and

generating, by the processor of the server, an ionosphere map that reflects the ionospheric activity, wherein the ionosphere map is generated utilizing the one or more estimated ionosphere delay values, the coordinates of the one or more pierce points received from the at least one rover, and the coordinates of the rover received from the at least one rover.

9. The method of claim 8, further comprising receiving, from the at least one rover, an identifier that uniquely identifies the rover and an identifier that uniquely identifies the corresponding GNSS satellite.

10. The method of claim 9, wherein a table is stored in the memory, wherein an entry of the table is configured to store the estimated ionosphere delay value calculated for the corresponding GNSS satellite, the coordinates of the pierce point associated with the corresponding GNSS satellite, the identifier that uniquely identifies the rover, the coordinates of the rover, and the identifier that uniquely identifies the corresponding GNSS satellite, a standard deviation of estimated ionosphere delay values, and a reference time at which the estimated ionosphere delay value was calculated.

11. The method of claim 8, wherein as the estimated ionosphere delay value increases, it is determined that the adverse effect of the ionospheric activity on the satellite signals is getting stronger.

12. The method of claim 8, further comprising transmitting the ionosphere map to one or more rovers, wherein each rover obtains a corresponding estimated ionosphere delay value as a correction for satellite range measurement utilizing the received ionosphere map.

13. The method of claim 12, wherein the particular estimated ionosphere delay value is obtained based on a rover pierce point falling within a particular cell of the ionosphere map

14. The method of claim 8 wherein the one or more estimated ionosphere delay values are received in one or more broadcast messages.

15. A rover, comprising:

a global navigation satellite systems (GNSS) receiver including a processor and a memory, the processor configured to;

receive one or more estimated ionosphere delay values where each estimated ionosphere delay value is calculated for a GNSS satellite in view of each of one or more other rovers, and wherein the estimated ionosphere delay value indicates an adverse effect of ionospheric activity on satellite signals transmitted by the corresponding GNSS satellite,

select a particular estimated ionosphere delay value of the one or more estimated ionosphere delay values, and

utilize the particular estimated ionosphere delay value as a correction for satellite range measurements obtained from the satellite signals transmitted by the given GNSS satellite or apply the particular estimated ionosphere delay value as a constraint to ionosphere delay estimated as an Extended Kalman Filter (EKF) state.

16. The rover of claim 15 wherein as the estimated ionosphere delay value increases, it is determined that the adverse effect of the ionospheric activity on the satellite signals is getting stronger.

17. The rover of claim 15 wherein the one or more estimated ionosphere delay values are received in one or more broadcast messages in a Peer-to-Peer network.

18. The rover of claim 15, wherein the rover is a single frequency rover, a dual frequency rover, or a multi-frequency rover.

19. The rover of claim 15, wherein the one or more estimated ionosphere delay values are received directly from the one or more other rovers or the one or more estimated ionosphere delay values are received from a central server that receives the one or more estimated ionosphere delay values from the one or more other rovers.

20. The rover of claim 18 wherein the processor is further configured to receive a rover identifier that uniquely identifies the at least one other rover and a GNSS identifier that uniquely identifies the corresponding GNSS satellite.