Improved Channel Error Calibration Algorithm for Azimuth Multichannel SAR Systems

Phase Inconsistency Error Compensation for Multichannel Spaceborne SAR Based on the Rotation-Invariant Property

“…By multiplying by the conjugate of P (f ), H (f ) can be made independent with Doppler frequency [15] and (4) is transformed to:…”

“…Usually, the covariance matrix of multi-channel SAR can be estimated from the sample covariance matrix R, which is the statistical average along the range dimension. Here, since the steering vectorH is independent of Doppler frequency, R can then be estimated along both range dimension and Doppler dimension [15]. As a result, the computational load will be significantly reduced and the SNR will increase, which is beneficial to the estimation of PI errors.…”

“…The parameters listed in Table I are used to simulate a set of spaceborne multi-channel SAR data. The added PI errors and corresponding results estimated by the proposed method in comparison with improved OS method (IOS) [15] and AWLS method are shown in Table II. It is obvious that the proposed method has better estimation results.…”

“…As for the computational load, the proposed method shares a similar complexity with the IOS method on O(M 3 ) [15] since they both adopt the Doppler-independent H in the procedures while the computational complexity of AWLS method is N a •O(M 3 ) where N a is the number of Doppler bins used. Note that a Doppler centroid error (100 Hz) was added for the proposed ESPRIT method in this experiment to show its ability to estimate and remove the Doppler centroid error.…”

Azimuth Phase Center Adaptive Adjustment upon Reception for High-Resolution Wide-Swath Imaging

“…However, a decreased number of activated elements reduces the transmit antenna gain and the transmit signal power. Secondly, azimuth channel errors can be compensated for by many recently proposed compensation methods [18,19,20]. However, since factors such as the manufacturing process, temperature and radiation that affect the characteristics of antenna are not fixed, these methods are unable to perfectly estimate or compensate for multichannel errors, especially when the signal-to-noise ratio (SNR) of the obtained raw data is not high enough.…”