Low-Cost, Precise Railroad GPS Vehicle Location System
National Technical Information Service
5301 Shawnee Road
If the precise location of both train and track maintenance vehicles and equipment could be determined automatically at central dispatch, it could significantly improve the safety and efficiency of train movements through track maintenance areas. This could be achieved using an automatic precise location system on the train and on the maintenance vehicles that automatically transmits their respective locations to central dispatch. This Innovations Deserving Exploratory Analysis (IDEA) project focuses on the feasibility of automatically and precisely determining the location of maintenance vehicles and equipment using a Global Positioning System (GPS) Vehicle Location System (GVLS). GVLS uses a GPS receiver augmented with dead reckoning sensors, in order to provide the vehicle location when GPS coverage is interrupted. The GVLS achieves the required position accuracy by using a sophisticated carrier differential GPS (CDGPS) position algorithm. This algorithm compares the GPS carrier phase measurements from the GVLS receiver with GPS carrier phase measurements from a nearby reference receiver at a known (surveyed) location. Using these measurements, the algorithm estimates and removes line-of-sight slant range errors, such as the unknown carrier (integer) biases, and determines the relative position between the two receivers. The reference receiver measurements are obtained from a High Accuracy - National Differential GPS (HA-NDGPS) reference station network, which is currently under development as an upgrade to the existing NDGPS reference station network. Under this feasibility study, a candidate CDGPS algorithm was selected based on a review of the technical literature. This algorithm was coded in Matlab and tested with archived GPS data. The data were obtained from the Continuously Operating Reference Station (CORS) Network that is administered by the National Geodetic Survey, NOAA.
This HSR-IDEA project was conducted by Sensis Corporation, Seagull Technology Center, Campbell, CA.
HSR-IDEA Project 52
Mueller, K Tysen
High-Speed Rail IDEA Program Project Final Report
Publisher: Transportation Research Board
Figures (25) ; Photos (1) ; References (28) ; Tables (14)
Highways; Operations and Traffic Management; Railroads
Nov 24 2009 9:34PM