Patent ID: 6072425
Filing Date: 2000-06-06
Classification: G01S,Y10S

Abstract:
An apparatus for correcting a Doppler frequency spectrum derived from terrain reflected signals having at least one pair of beams through which signals are radiated and signals returned from a reflecting terrain are received, each of the at least one pair having a main beam with a main beam axis and an auxiliary beam with an auxiliary beam axis, the auxiliary beam axis positioned relative to the main beam axis at a predetermined angular offset and wherein signals representative of a main beam Doppler spectrum from signal returns within said main beam and signals representative of an auxiliary beam Doppler spectrum from signal returns within said auxiliary beam are derived from received signals comprising:a beam bias estimator coupled to receive said main and auxiliary beam Doppler spectrum representative signals, attitude data of said at least one pair of beams, and propagating medium characteristics, constructed and arranged to provide Doppler spectrum amplitude correction factors; anda Doppler data processor, coupled to said beam bias estimator, constructed and arranged to apply said Doppler spectrum amplitude correction factor to said main beam Doppler spectrum.