The Analysis of Spaceborne SAR Interferometry Based on Strapdown Inertial Navigation Mechanism and Maximum Likelihood Method

In this paper, a spaceborne SAR interferometry system operates on the strapdown inertial navigation mechanism, which is based on maximum likelihood phase estimation method. It has been shown using simulated data that phase estimation of cross-track multi-baseline synthetic aperture radar (SAR) interferometric data is most efficiently achieved through a maximum likelihood phase estimation method. With the help of strapdown inertial navigation mechanism and compared to simulated data, dealing with real data implies that several calibration steps be carried out to ensure that the data fits the model. It is well known that a nonlinear frequencymodulation (NLFM) chirp waveform can shape the signal’s power spectral density and provide a radar matched filter output with lower sidelobes without loss of the signal-to-noise ratio. The strapdown inertial navigation mechanism can measure the apex angle and azimuth angle, the motion attitude of the carrier can be calculated by the three-axis displacement and revolution which are measured by this system. Compares the value of spaceborne SAR interferometry with the value which is measured by strapdown inertial navigation mechanism, the measurement accuracy will be improved by the analysis of strapdown inertial navigation mechanism and maximum likelihood phase estimation method.