| The gravity measurement is widely used in the geodesy, military mapping, space science, physics of earth and so on. Our country can only rely on the imported gravimeters for airborne gravity measurement at present, so to develope airborne gravimeter independently is of great significance to our mineral resources exploration and surveying. The airborne gravimeter may be categorized into platform gravimeter and strapdown gravimeter. Compared to platform gravimeter, strapdown gravimeter has the advantage of low cost, small volume and high reliability.Considering the above background, research on key technologies of strapdown moving base gravimeter was carried out, especially for the key technologies of gravity data processing, clock synchronization and data storage. Main research contents are as follows.For software aspects, the gravity equations were deduced and a variety of gravity disturbance correction formulas were given. Error source of airborne gravimeter was analyzed and system index allocation was given. The processing flow of gravity data was detaily introduced, and filter method of gravity anomaly was focused studied: on the one hand, model of gravity anomaly was built and gravity anomaly was extracted through kalman filter; on the other hand, from selection of window function to determination of cutoff frequency, FIR filter was designed in detail to extract gravity data. Finally the two filters were compared and discussed through experiment data.For hardware aspects, precision requirement of time synchronization was analyzed. The overall scheme of time synchronization and the specific time correction scheme were designed. Hardware synchronization clock was realized through FPGA, and Hardware synchronization accuracy can reach microsecond level. The original data of gravimeter is stored through ARM processor, and storage medium is SD card. From DMA communication to SD storage, system storage project was devised and the feasibility of the method was demonstrated through experiment. |
PDF Full Text Request