Key techniques of doppler delay mapping receiver for GPS remote sensing

The principle of airborne ocean wind-field detecting system based on GPS scatter signal is proposed. The architecture of Doppler Delay Mapping Receiver (DDMR) was introduced in this paper. Six key techniques were discussed such as improving the Signal Noise Ratio of reflected signal, dual radio frequency front-end, calculating the specular point for Doppler and code delay, implement for multi-channel correlator, reflected signal open loop tracking, reflected signal accumulating. Real time data collection campaigns were done at Sanya near sea with the Doppler Delay Mapping Receiver mounted on an airplane. Results show that the receiver can simultaneously receive direct and ocean scattered GPS signal, correctly calculate specular point, successfully measure the ocean scattered signals correlated power for Doppler and Code Delay. Two-dimension data is valid for the ocean wind retrieval. The technique can also be used in land moist sensing, ocean wave height detecting.