Patent ID: 8044859

Claim:
A method of determining bias error in a geolocation system, comprising: transmitting from a transmitter a reference beacon signal containing position information including at least one of a position of the transmitter at a time of fix and an estimate of the position of the transmitter at a time of trans mission of the reference beacon signal, wherein the reference beacon signal contains motion information relating to the transmitter; receiving the reference beacon signal at a plurality of collection platforms; determining a position measurement of the transmitter based on at least one of a time of arrival and a frequency of arrival of the reference beacon signal at the plurality of collection platforms; determining a first bias error based on the position measurement of the transmitter and the position information contained in the reference beacon signal; determining a velocity measurement of the transmitter based on a frequency of arrival of the reference beacon signal at each of the plurality of collection platforms; and determining a second bias error based on the velocity measurement of the transmitter and the motion information contained in the reference beacon signal.