Patent ID: 6795019
Filing Date: 2004-09-21
Classification: G01S

Abstract:
A method for calibrating a wireless location system comprising the steps of:transmitting a signal from an unknown location; receiving the signal at first and second spatially oriented receivers positioned at known locations, each receiver having clocks and measuring at each of first and second receivers a Time of Arrival, Time Difference of Arrival, or Frequency Difference of Arrival of Signals reflected or refracted to each of the two receivers by a proxy reference transmitter comprising one of a natural or man-made object; determining an error value based on the Time of Arrival, Time Difference of Arrival, or Frequency Difference of Arrival of Signals; and using the error value to calibrate the clocks at the receivers using a clock offset to minimize the errors in subsequent measurements and/or apply corrections to any prior, concurrent or subsequent measurements.