New Doppler frequency rate estimation method for spaceborne synthetic aperture radars

The Doppler frequency rate is an important parameter in synthetic aperture radar imaging, which is used to perform the azimuth compression. The Doppler frequency rate can be estimated through the measurement of the sensor trajectory and attitude or through the analysis of the characteristics of the target echoes. The latter method will generally give a high accuracy. Currently, there are quite a few techniques for estimating the Doppler frequency rate, with some having a high accuracy but requiring a large amount of computation, and others requiring a smaller amount of computation but having a lower accuracy. Based on the concept of minimum entropy, a new technique for estimating the Doppler frequency rate is proposed which not only gives a high accuracy but also requires a small amount of computation.