Proc. SPIE. 4894, Microwave Remote Sensing of the Atmosphere and Environment III
KEYWORDS: Digital signal processing, Calibration, Synthetic aperture radar, Computer simulations, Signal processing, Antennas, Signal detection, Electromagnetic simulation, Device simulation, Received signal strength
Ground-based test and calibration of Synthetic Aperture Radar (SAR) is a very complex program. It needs a practical method and technique to provide a full return signal simulation over the range of in-orbit operating conditions before launch for such a program. Compared with conventional ground-based test methods, the Return Signal Simulator (RSS) is more effective for full system validation and makes test program and procedure greatly simplified. Based upon signal processing of SAR, an advanced RSS system is designed. By using chirp regeneration method, the RSS can achieve 1-10ms time delay between SAR transmitting and simulated signal return, which will realize round trip path delay simulation for various orbit height; By using digital synthesizing method, various target return signal can be simulated. So the RSS system can make prelaunch performance of SAR well known, and this will be very helpful for radiometric calibration after launch. This paper will give detailed description on the RSS system design with its means of testing and calibrating of satellite SAR.
A scheme of Integrative Return Signal Simulator (IRSS) of satellite altimeter and scatterometer is designed. The IRSS realized by the scheme can compensate the insufficiency of general measure and calibration equipment. It can calibrate easily the transfer function of satellite altimeter and scatterometer and test the property of software and hardware in laboratory and launching site. The IRSS is based on the principle of the pulse regeneration and the return signal is synthesized at digital method. The scheme can realize modulation of pulse width and Doppler frequency shift for return signal. The problems such as accurate delay of radio-frequency and the phase difference shift and so on can be resolved. The simulation results show that the synthesized return signal not only may satisfy fully the statistical law of actual return signal but also can include information concerned for testing the property of altimeter and scatterometer. The method lays a reference for developing other type of Return Signal Simulator (RSS) in future.