The application of GPS to high frequency oceanic detecting radar

High frequency oceanic detecting radar is a powerful tool to monitor environment of ocean. It can detect the parameters of wind, wave and current. While the radar is fabricated, it must be calibrated by responder first. And the position of responder can be obtained by GPS. In the paper a novel application of GPS to high frequency oceanic detecting radar is discussed. The data format of the GPS receiver is commonly NEMA0183 communication standard. In the paper this standard is analyzed and the characteristic is found. There are large amount of data in the format, including latitude, longitude, altitude, velocity, date, time, course and satellite status. It makes a heavy burden while communicating between GPS and responder. So we must reduce the output data of GPS receiver. Among twelve items of the data format, only the degree of latitude, the hemisphere of latitude, the degree of longitude and the hemisphere of longitude are useful. By extracting these four items and wiping off the others, the data are reduced efficient. Then the reduced data are transmitted to the station of radar by data radio. So the position of the responder can be obtained. In addition, for the update rate of data is 1 time/second, it is to say the data transmitted in one second are the same, the transmitting rate can be set as N second. N is configured as we need. The block diagram of the system is given in the paper. The functions of each part can be achieved by FPGA chips and VHDL. The simulation proved that the transmitted data have been reduced greatly by the system we proposed here. It is only ten percent of the original data.