Abstract: A system includes a global positioning system receiver to determine position of a railroad vehicle, a predetermined track map of possible coordinates of the vehicle, motion sensors providing a positive bias error to determine change in location of the vehicle, an acceleration sensor to determine acceleration of the vehicle, and a processor to vitally determine the location and the location uncertainty of the vehicle on the track map. The processor verifies one motion sensor with another motion sensor, determines a slip or slide condition of the vehicle from one of the motion sensors, determines speed and position of the vehicle from the acceleration sensor during the slip or slide condition, verifies the position of the vehicle from the global positioning system receiver based upon the track map, and corrects the positive bias error of the motion sensors using the position of the vehicle from the global positioning system receiver.

Abstract: A system includes a global positioning system receiver to determine position of a railroad vehicle, a predetermined track map of possible coordinates of the vehicle, motion sensors providing a positive bias error to determine change in location of the vehicle, an acceleration sensor to determine acceleration of the vehicle, and a processor to vitally determine the location and the location uncertainty of the vehicle on the track map. The processor verifies one motion sensor with another motion sensor, determines a slip or slide condition of the vehicle from one of the motion sensors, determines speed and position of the vehicle from the acceleration sensor during the slip or slide condition, verifies the position of the vehicle from the global positioning system receiver based upon the track map, and corrects the positive bias error of the motion sensors using the position of the vehicle from the global positioning system receiver.

Abstract: A coordinate transformation system determines the position of a railroad vehicle. The system includes a global positioning system receiver outputting a longitude and a latitude of the vehicle. Each of the longitude and latitude is angular position bounded by a first predetermined longitude and a greater second predetermined longitude or a first predetermined latitude and a greater second predetermined latitude, respectively. A processor includes an input inputting the longitude and the latitude, a routine determining a first distance approximating a distance corresponding to the latitude as a function of the latitude, a third angular position and a first predetermined value, determine a second distance approximating a distance corresponding to the longitude as a function of the longitude, a fourth angular position and a second value, and an output outputting the first and second distances.