Navigation system and method using RTK with data received from a mobile base station

Patent metadata

Field	Value
Publication number	US-9846241-B2
Application number	US-201514659485-A
Country	US
Kind code	B2
Filing date	Mar 16, 2015
Priority date	Jul 30, 2010
Publication date	Dec 19, 2017
Grant date	Dec 19, 2017

Abstract

In a system for navigating a moving object according to signals received from satellites, a moving object receives mobile base data from a mobile base station, the received mobile base data including satellite measurement data of the mobile base station, the satellite measurement data of the mobile base station including code measurements and carrier phase measurements for the plurality of satellites, and position-related information of the mobile base station. In accordance with the satellite navigation data for the moving object and the received mobile base data, the moving object performing a real-time kinematic (RTK) computation process to resolve carrier phase ambiguities and determine a relative position of the moving object relative to the mobile base station. A signal reporting information corresponding to the relative position is sent via a transmitter of the moving object.

First claim

We claim:

1. A method for navigating a moving object according to signals from satellites, the method comprising:
at a moving object,
receiving satellite navigation signals from a plurality of satellites;
generating, from the received satellite navigation signals, satellite navigation data for the moving object, the satellite navigation data for the moving object including code measurements and carrier phase measurements for the plurality of satellites, wherein the moving object comprises a system that includes a first receiver and a first transmitter;
receiving mobile base data from a mobile base station, the received mobile base data including satellite measurement data of the mobile base station, the satellite measurement data of the mobile base station including code measurements and carrier phase measurements for the plurality of satellites, and position-related information of the mobile base station;
in accordance with the satellite navigation data for the moving object and the received mobile base data, performing a real-time kinematic (RTK) computation process to resolve carrier phase ambiguities and determine a relative position of the moving object relative to the mobile base station at a first specific time;
determining, for a current time,
a velocity of the mobile base station in accordance with one or more position updates for the mobile base station, comprising changes in position of the mobile base station relative to a position of the mobile base station at the first specific time; and
a current relative position of the moving object relative to the mobile base station based on the relative position of the moving object relative to the mobile base station at the first specific time, a change in position of the moving object from the first specific time to the current time, and the determined velocity of the mobile base station; and

sending, via the first transmitter of the moving object, a signal reporting information corresponding to the relative position;

wherein
determining, for a current time, the current relative position of the moving object relative to the mobile base station includes:
determining a projected change in position of the mobile base station in accordance with the determined velocity of the mobile base station and a length of time between the current time and the first specific time; and
determining the current relative position of the moving object relative to the mobile base station based on the relative position of the moving object relative to the mobile base station at the first specific time, a change in position of the moving object from the first specific time to the current time, and the determined projected change in position of the mobile base station.

2. The method of claim 1 , wherein the mobile base station and mobile object are both vehicles.

3. The method of claim 1 , wherein the mobile base station and mobile object are both vehicles, and the mobile object is configured to maintain a predefined relative position of the moving object relative to the mobile base station.

4. The method of claim 1 , wherein
the mobile base data received from the mobile base station includes, at a first sequence of times, position data indicating a position of the mobile base station at the first sequence of times and the satellite measurement data of the mobile base station for the first sequence of times; and
the method includes, for the first sequence of times, performing the RTK computation process to determine the relative position of the moving object relative to the mobile base station at the first sequence of times, and determining a position of the moving object at each time in the first sequence of times based on the position of the mobile base station at the first sequence of times and the determined relative position of the moving object relative to the mobile base station at the first sequence of times.

5. The method of claim 1 , wherein the mobile base data received from the mobile base station includes, at a first sequence of times corresponding to epoch boundaries, position data indicating a position of the mobile base station, and at second sequences of times corresponding to update times between the epoch boundaries, position update information indicating a change in position of the mobile base station since a last epoch boundary; and wherein determining, for a current time, the velocity of the mobile base station includes determining the velocity in accordance with the position update information for a respective time, in the second sequences of times, corresponding to the current time.

6. The method of claim 5 , wherein performing the real-time kinematic (RTK) computation process includes determining a position of the moving object at times corresponding to both the first sequence of times and the second sequences of times.

7. The method of claim 1 , wherein performing the real-time kinematic (RTK) computation process includes generating differential carrier-phase measurements based on the satellite measurement data of the mobile base station received from the mobile base station and the satellite measurement data for the moving object, and resolving whole-cycle ambiguities in the differential carrier-phase measurements.

8. The method of claim 1 , wherein the relative position of the moving object relative to the mobile base station comprises a relative position vector or a differential position value.

9. The method of claim 1 , wherein the determined velocity of the mobile base station comprises a smoothed velocity of the mobile base station determined, at the moving object, based on historic information for the mobile base station.

10. The method of claim 5 , wherein determining the current relative position of the moving object relative to the mobile base station includes determining, for a current time, a current relative position of the mobile base station based on a sum of (A) a change in position of the mobile base station between the first specific time and a second time corresponding to a last time in the second sequences of times, and (B) a projected change in position of the mobile base station in accordance with the determined velocity of the mobile base station and a length of time between the current time and the second time.

11. A system for navigating a moving object according to signals from satellites, the system comprising:
one or more processors;
a satellite receiver to receive satellite navigation signals from a plurality of satellites;
a signal receiver to receive mobile base data from a mobile base station, the received mobile base data including satellite measurement data of the mobile base station, the satellite measurement data of the mobile base station including code measurements and carrier phase measurements for the plurality of satellites, and position-related information of the mobile base station;
memory storing a determining module to be executed by the one or more processors, the determining module to:
perform a real-time kinematic (RTK) computation process, in accordance with satellite navigation data for the moving object, generated from the received satellite navigation signals from the plurality of satellites, and the received mobile base data, to resolve carrier phase ambiguities and determine a relative position of the moving object relative to the mobile base station at a first specific time; and
determine, for a current time,
a velocity of the mobile base station in accordance with one or more position updates for the mobile base station, comprising changes in position of the mobile base station relative to a position of the mobile base station at the first specific time; and
a current relat

Assignees

• Deere & Co

Inventors

• Dai Liwen L
• Shao Yunfeng

Classifications

• G01S19/43

  using carrier phase measurements, e.g. kinematic positioning; using long or short baseline interferometry · CPC title

• G01S19/51

  Relative positioning · CPC title

• G01S5/0072

  Transmission between mobile stations, e.g. anti-collision systems · CPC title

• G01S19/44 Primary

  Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method · CPC title

• G01C21/20

  Instruments for performing navigational calculations (G01C21/24, G01C21/26 take precedence) · CPC title