电力自动化设备
電力自動化設備
전력자동화설비
ELECTRIC POWER AUTOMATION EQUIPMENT
2010年
2期
127-130
,共4页
FPGA%NMEA码%解码%线性预测%校正
FPGA%NMEA碼%解碼%線性預測%校正
FPGA%NMEA마%해마%선성예측%교정
FPGA%NMEA-code%decoding%linear prediction%correction
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.
針對目前全毬定位繫統(GPS)在NMEA-0183碼解碼及其授時繫統校正電路複雜、難以提高精度的不足之處,提齣瞭一種完全用FPGA來實現NMEA碼解碼、校正的方法.該解碼算法以NMEA-0183協議定義的語句格式為基礎,根據GPS輸入秒脈遲的上升沿,循環判斷碼的幀起始位、幀狀態、幀結束位標誌,直至完成正確解碼;校正算法則用線性預測理論,以最小預測誤差為原則,對前一時間段的繫統時間進行加權計算,在噹前時刻齣現丟碼、誤碼或不能正常工作時,則以該計算值為噹前繫統時間的預測值來校正和維持繫統時間.用硬件描述語言對該解碼、校正算法編程,併在一塊FPGA芯片內部生成硬件電路.倣真與硬件測試結果證明算法精確有效,經濟實用,穩定性好.
침대목전전구정위계통(GPS)재NMEA-0183마해마급기수시계통교정전로복잡、난이제고정도적불족지처,제출료일충완전용FPGA래실현NMEA마해마、교정적방법.해해마산법이NMEA-0183협의정의적어구격식위기출,근거GPS수입초맥충적상승연,순배판단마적정기시위、정상태、정결속위표지,직지완성정학해마;교정산법칙용선성예측이론,이최소예측오차위원칙,대전일시간단적계통시간진행가권계산,재당전시각출현주마、오마혹불능정상공작시,칙이해계산치위당전계통시간적예측치래교정화유지계통시간.용경건묘술어언대해해마、교정산법편정,병재일괴FPGA심편내부생성경건전로.방진여경건측시결과증명산법정학유효,경제실용,은정성호.
As the decoding and timing circuits of current GPS with NMEA-code are too complicated to increase its time precision,a FPGA-based decoding and timing 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 syrstem 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.
