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An airborne MMW cross-track InSAR system is discussed. The system design is presented based on MMW solid transmitter, dual-channel receivers, low phase noise signal generator, gyro-stabilized mount, position and orientation system. The system's parameters are analyzed. A performance simulation result denotes that the elevation accuracy (0.5-1m) is possible for the MMW InSAR with 0.5m resolution.

Based on dual frequencies-dual apertures spaceborne SAR (synthetic aperture radar), a new SAR operation mode with four receiving channels is presented in this paper. High resolution imaging and moving target indication (MTI) are studied with this new mode. The coherent accumulation (CA) method, which combines dual channels data, is used to enhance the range resolution. With the data from all channels, the two aperture interferometric processing is executed to implement clutter cancellation. A pair of the clutter suppressed data are employed to implement double carrier frequency conjugated processing (DCFCP), then MTI processing is completed, followed by moving target imaging. The simulation results show the validity of the signal processing method and the feasibility of this new SAR mode.

According to the characteristic that the bandwidth of spaceborne SAR is generally quite wide, a new method called "Sub-band Double Carrier Frequency Conjugated Processing" is presented in this paper. The approach can decrease the equivalent central frequency of the synthetic signal and remove the Doppler ambiguity. Consequently, Keystone transform can be used to correct the linear range migration of the fast moving targets with low input SNR. After the target range curvature is corrected, time-frequency analysis can be used to implement low resolution imaging and targets detecting. The radial velocities of the targets can be obtained from targets detection, and high resolution imaging process can be completed to each moving target. The simulation results show the effectiveness of the new method.