Study Ht-2 Satellite Radar Altimeter Calibration Based On Retrun Signal Simulator

Ocean plays an important role in the climate。Radar altimeter is widely used to detect the climate change. Ocean return signal simulator is successfully used on altimeter calibration by NASA and ESA.The ocean return signal simulator can be divided into two kinds: signal repeater and signal reconstructive simulator.The theory and property of signal reconstructive simulator were detailed in this article.The ocean return signal was analyzed and the ocean return wave spectrum was digitally synthesized by the computer. In order to precisely calibrate radar altimeter, the biases such as quadratic phase bias, amplitude and phase bias, delay bias were detailed. The whole system bias on return signal simulator was calculated. The result shows whole system bias satisfies calibration requirement.The simulator diagram was detailed in this dissertation , the DSP&FPGA was used in the digital control unit. Such devise not only ensure the system stability but also realize the data process synchronized.The major contribution points are as following:(1)The signal return wave was digitally synthesized by the computer. The spectrum can simulate the point response and ocean target,etc. FPGA and DSP technique were used to ensure the system stability.(2) Quadratic phase bias, amplitude and phase bias, delay bias were quantitive analyzed, such work are used on the simulator properties choice. The whole system bias on simulator satisfies the calibration requirement.(3) The inner channel test result of simulator matches the calculation result. The calibration test on HY-2 radar altimeter was designed and the test result testify the radar altimeter satisfied 4 cm precision.In the last section The whole work was conclude. Some problems were pointed and follow work was forwarded.