Patent ID: 7489937
Filing Date: 2009-02-10
Classification: G01S

Abstract:
1. A method of detecting emitter movement, the method comprising: acquiring a first measured time difference of arrival (TDOA) and a second measured TDOA corresponding to a signal received from an emitter; acquiring a first measured frequency difference of arrival (FDOA) and a second measured FDOA corresponding to the signal received from the emitter; estimating an emitter location based on the first TDOA and the second TDOA; utilizing the estimated emitter location to estimate a third FDOA and a fourth FDOA; generating a first comparison value by finding the difference between the first FDOA and the third FDOA; generating a second comparison value by finding the difference between the second FDOA and the fourth FDOA; and determining that the emitter is moving if either the first comparison value is greater than an error value or the second comparison value is greater than the error value.