Patent ID: 9297884
Filing Date: 2016-03-29
CPC Classification: G01R,G01S

Claim Text:
1. A computer-implemented method of generating a polynomial approximation of a time-varying carrier frequency of a received signal, the method comprising: (A) computing, in a processor of a computing system, a cross-spectral surface of the received signal, wherein the cross-spectral surface is a function of at least time and frequency; (B) for each of a first series of times, determining, in the processor an initial frequency estimate to be a point on the cross-spectral surface; (C) performing, in the processor, a first polynomial interpolation based on the initial frequency estimates to generate an initial frequency polynomial; (D) integrating, in the processor, the initial frequency polynomial to generate an initial phase polynomial; (E) processing, in the processor, the received signal to generate a basebanded signal using the initial phase polynomial; (F) for each of a second series of times, determining, in the processor, an unwrapped phase value of the basebanded signal; (G) performing, in the processor, a second polynomial interpolation based on the unwrapped phase values to generate a residual phase polynomial; (H) generating, in the processor, an updated phase polynomial based on the initial phase polynomial and the residual phase polynomial; and (I) differentiating, in the processor, the updated phase polynomial to generate the polynomial approximation of the time-varying carrier frequency of the received signal.