摘要
针对目前全球定位系统(GPS)在NMEA-0183码解码及其授时系统校正电路复杂、难以提高精度的不足之处,提出了一种完全用FPGA来实现NMEA码解码、校正的方法。该解码算法以NMEA-0183协议定义的语句格式为基础,根据GPS输入秒脉冲的上升沿,循环判断码的帧起始位、帧状态、帧结束位标志,直至完成正确解码;校正算法则用线性预测理论,以最小预测误差为原则,对前一时间段的系统时间进行加权计算,在当前时刻出现丢码、误码或不能正常工作时,则以该计算值为当前系统时间的预测值来校正和维持系统时间。用硬件描述语言对该解码、校正算法编程,并在一块FPGA芯片内部生成硬件电路。仿真与硬件测试结果证明算法精确有效,经济实用,稳定性好。
As the decoding and increase its time precision, a timing circuits of current GPS with FPGA-based decoding and timing NMEA-code are too complicated to way is proposed,which,based on NMEA-0183 protocol,detects cyclically the start bit,status bit and ending bit of NMEA code frame according to the uprising edge of second pulse from GPS till the accomplishment of precise decoding. Based on the theory of linear prediction and with the principle of minimal prediction error,the correction algorithm carries out the weighted calculation with the system time of last period,which is taken as the predicted current system time to correct and maintain system time when there is code loss,code error or abnormal working conditions. The algorithm is programmed with hardware description language and burned on a FPGA chip. Simulation and HW test prove it is accurate, effective, economical and stable.
出处
《电力自动化设备》
EI
CSCD
北大核心
2010年第2期127-130,共4页
Electric Power Automation Equipment
关键词
FPGA
NMEA码
解码
线性预测
校正
FPGA
NMEA-code
decoding
linear prediction
correction language and burned on a and stable.
