数据收集系统下行频偏校准与点频值计算

风云二号（ＦＹ－２）卫星在轨运行期间本振源必定产生一定的频率偏移，这就影响了数据收集平台接收系统（ＤＣＰＲ）相应于各种平台的报文锁相环路的频率捕获范围，严重时将无法解调出各种平台收集的气象数据，整个系统也将无法正常工作。为解决上述问题，介绍了ＤＣＰＲ下行频偏校准及点频值计算的方法。通过ＦＹ－２卫星在轨测试表明，在随机干扰比较严重的情况下，ＤＣＰＲ对各种平台报文接收解调的成功率优于９８％，取得了令人满意的结果。

METHOD OF CORRECTING DOWN LINE FREQUENCY SHIFT AND CALCULATING POINT FREQUENCY

During FY 2 satellite operating in orbit ,the local oscillator will have some frequency shift.It limits the frequency capture range of Data Collection Platform Receiving system(DCPR) corresponding to phase-locked loop of Data Collection Platform (DCP) information. In some serious eases the meteorological data collected by DCP can't be demodulated,so the system can't run normally. In order to resolve the above-mentioned problem, in this paper the method of down line frequency shift and calculating point frequency is discussed.The result of testing FY 2 in orbit is satisfactory and shows that even if random interference is much serious, the succes probability of DCPR reception and modulation is over 98%.