Entropy-minimization based I/Q channel errors compensation for stepped frequency radar

A new I/Q channel errors compensation method is presented for superheterodyne receiver of stepped-frequency imaging radar. Different from using a test signal or calibration reflector to survey the I/Q channel errors in conventional techniques, this method is based on radar echoes and derives the I/Q channel errors by searching the minimum entropy of the range profile in error space. To speed up the error searching procedure, stage by stage approach (SSA) is used to solve the minimization problem. The Hermitian images are significantly suppressed by correcting the I/Q samples with the estimated errors. Finally, the method is validated by simulation.