Inertial track measurement system and methods
A track geometry measurement system includes a plurality of wheels, a frame, an inertial measurement unit, a global positioning system, and a processor. The plurality of wheels are operable to trail over rail track. The frame is coupled to the wheels. The inertial measurement unit (IMU) is coupled to the frame. The global positioning system (GPS) is coupled to the frame. The processor is configured to determine a relative position of a portion of the frame based on data from the GPS and data from the IMU.
1. A track geometry measurement system, comprising:
a plurality of wheels operable to trail over rail track;
a frame coupled to the wheels;
an inertial measurement unit (IMU) coupled to the frame;
a global positioning system (GPS) coupled to the frame;
a memory configured to store IMU data; and
a processor configured to
determine a relative position of a portion of the frame based on data from the GPS and data from the IMU,
determine a signature based on the data from the IMU, and
search IMU data stored in the memory for the signature to align the position with the IMU data stored in the memory.
2. The track geometry measurement system of claim 1 , wherein the processor is configured to determine a lower precision location based on the data from the GPS and a higher precision location based on the IMU.
3. The track geometry measurement system of claim 2 , wherein the processor is configured to determine a chord between two points of GPS data and to determine a location of the chord between the two points based on the IMU data.
4. The track geometry measurement system of claim 1 , wherein the processor is configured to align the data using cross-correlation.
5. The track geometry measurement system of claim 1 , wherein the memory is configured to store GPS data, and the processor is configured to determine a lower precision location by searching the memory based on the GPS data and thereafter improving the precision of the determined location by searching the memory based on the IMU data associated proximal to the lower precision location.
6. The track geometry measurement system of claim 1 , wherein the processor is configured to determine a track gauge based on the IMU data.
7. The track geometry measurement system of claim 1 , wherein the processor is configured to determine a rail height based on the IMU data.
8. The track geometry measurement system of claim 1 , wherein the processor is configured to determine a curvature of a rail based on the IMU data.
9. The track geometry measurement system of claim 1 , wherein the processor is configured to determine a difference between the rail height and a desired rail height.
10. A track maintenance vehicle, comprising:
the track geometry measurement system of claim 9 ; and
a work head configured to perform maintenance on a rail of the rail track based on the determined difference.
11. The track geometry measurement system of claim 1 , further comprising a laser measurement system coupled to the frame, the laser measurement unit configured to measure a profile of a rail of the track.
12. The track geometry system of claim 11 , wherein the processor is configured to determine the relative position based on data from the laser measurement unit.
13. The track geometry measurement system of claim 12 , wherein the processor is configured to determine a lower precision location based on the data from the GPS and a higher precision location based on the laser measurement unit.
14. A tamper, comprising:
a plurality of wheels operable to trail over rail track;
a frame coupled to the wheels;
a work head operable to tamp ballast and coupled to the frame;
an inertial measurement unit (IMU) coupled to the frame;
a global positioning system (GPS) coupled to the frame;
a memory configured to store IMU data; and
a processor configured to
determine a relative position of a portion of the frame based on data from the GPS and data from the IMU and to control the work head to tamp the ballast based on the IMU data,
determine a signature based on the data from the IMU, and
search IMU data stored in the memory for the signature to align the position with the IMU data stored in the memory.
15. The tamper of claim 14 , wherein the processor is configured to determine the relative position based on the data from the IMU while the tamper is travelling over the rails.
16. The tamper of claim 14 , wherein the processor is configured to determine the relative position based on the data from the IMU while the tamper is travelling over the rails and before the tamper reaches a location at which the work head begins tamping the ballast.
17. The tamper of claim 14 , wherein the memory is configured to store GPS data, and the processor is configured to determine a lower precision location by searching the memory based on the GPS data and thereafter improving the precision of the determined location by searching the memory based on the IMU data associated proximal to the lower precision location.
18. The tamper of claim 14 , wherein the processor is configured to determine a position of a rail based on the IMU data, to determine a difference between the position of the rail and a desired position, and control the work head to tamp the ballast based on the determined difference.