The Design Of BDS B1 Frequency GEO Satellite Acquisition Baseband

BDS is a global satellite navigation system which is constructed independently by China. The GEO satellite which is an important part of BDS constellation space has a dual function radiodetermination and SMS messages. However, the acquisition sensitivity of GEO satellite is low because the rate of its navigation data is up to 500bps. Therefore, in order to take advantage of it, the acquisition sensitivity must be improved.Firstly, the acquisition performance of BDS receiver is listed separately. The high sensitivity acquisiotn methods of other navigation systems which are similar to the BDS GEO satellite are summarized by an extensive literature review. Then, according to the special signal structure of BDS GEO satellite, a multi-bit correlation acquisition algorithm is designed. The coherent integration time of it is up to 6ms. The algorithm is simulated by MATLAB and the result is consistent with theoretical calculations. Finally, under the dual constraints of acquisition performance and hardware resource consumption, the acquisition baseband of BDS GEO satellite is designed with veilog language.The BDS GEO satellite acquisiotn baseband circuit was implemented in FPGA. The FPGA model is EP4CE115F23I7 of Cyclone IV E. On which the multi-bit correlation algorithms verified. To compare the acquisition performance, a test platform was designed with same BDS singal source, which could test the BDS GEO baseband and other BDS receiver. Test results showed that the designed BDS GEO acquisition baseband had a higher acquisiotn sensitivity and shorter acquisition time than other similar products. The BDS GEO acquisition baseband was implemented on SMIC 40nm LP process, under the conditions of 1.1V power supply and 16.368MHz system clock, the area and power of circuit were 0.8mm2 and 7.914mW.