中国惯性技术学报
中國慣性技術學報
중국관성기술학보
JOURNAL OF CHINESE INERTIAL TECHNOLOGY
2013年
4期
500-505
,共6页
曾庆喜%唐琳琳%王庆%陈小惠
曾慶喜%唐琳琳%王慶%陳小惠
증경희%당림림%왕경%진소혜
GPS软件接收机%载波频率%捕获%宽载噪比%相位测量%长相干处理
GPS軟件接收機%載波頻率%捕穫%寬載譟比%相位測量%長相榦處理
GPS연건접수궤%재파빈솔%포획%관재조비%상위측량%장상간처리
GPS software receiver%carrier frequency%acquisition%wide carrier-to-noise ratio%phase measurement%long coherent processing
为给GPS软件接收机的跟踪环提供精确的初始条件,捕获后得到的载波频率应在几十Hz范围内,所以必须寻找一种既能精确测量载波多普勒频移,又能有较快运算速度的方法。针对这一特点,提出了一种载噪比较高时采用相位测量和较低时采用长相干处理的载波频率精确估计策略。利用Matlab 仿真产生的卫星中频数据作为数据源对该策略进行验证,结果表明当输入信号的载噪比大于35.5 dB·Hz的时候,相位测量算法得到的多普勒频率值的误差保持在约10 Hz之内。对于微弱信号的捕获,如果将相干处理的时间从200 ms扩展到600 ms,捕获频率的误差从3 Hz减小到0.5 Hz。此外,与传统的FFT方法相比,该方法的加法和乘法运算量分别降低了96.2%和35%。测试结果体现了该算法的有效性和优越性。
為給GPS軟件接收機的跟蹤環提供精確的初始條件,捕穫後得到的載波頻率應在幾十Hz範圍內,所以必鬚尋找一種既能精確測量載波多普勒頻移,又能有較快運算速度的方法。針對這一特點,提齣瞭一種載譟比較高時採用相位測量和較低時採用長相榦處理的載波頻率精確估計策略。利用Matlab 倣真產生的衛星中頻數據作為數據源對該策略進行驗證,結果錶明噹輸入信號的載譟比大于35.5 dB·Hz的時候,相位測量算法得到的多普勒頻率值的誤差保持在約10 Hz之內。對于微弱信號的捕穫,如果將相榦處理的時間從200 ms擴展到600 ms,捕穫頻率的誤差從3 Hz減小到0.5 Hz。此外,與傳統的FFT方法相比,該方法的加法和乘法運算量分彆降低瞭96.2%和35%。測試結果體現瞭該算法的有效性和優越性。
위급GPS연건접수궤적근종배제공정학적초시조건,포획후득도적재파빈솔응재궤십Hz범위내,소이필수심조일충기능정학측량재파다보륵빈이,우능유교쾌운산속도적방법。침대저일특점,제출료일충재조비교고시채용상위측량화교저시채용장상간처리적재파빈솔정학고계책략。이용Matlab 방진산생적위성중빈수거작위수거원대해책략진행험증,결과표명당수입신호적재조비대우35.5 dB·Hz적시후,상위측량산법득도적다보륵빈솔치적오차보지재약10 Hz지내。대우미약신호적포획,여과장상간처리적시간종200 ms확전도600 ms,포획빈솔적오차종3 Hz감소도0.5 Hz。차외,여전통적FFT방법상비,해방법적가법화승법운산량분별강저료96.2%화35%。측시결과체현료해산법적유효성화우월성。
To provide accurate initial condition for the tracking loop in a GPS software receiver, the acquired carrier frequency should be within dozens of Hz. Therefore, a method that can precisely and quickly measure Doppler frequency shift should be acquired. An estimation method for fine carrier frequency is proposed, in which the phase measurement method is used under high CNR, and the long coherent processing method is used under low CNR. Then the method is tested based on the intermediate frequency data generated by Matlab simulation. The results show that, when CNR of the input signal is higher than 35.5 dB·Hz, the error of Doppler frequency obtained by phase measurement algorithm is kept within 10 Hz. For weak signals, the frequency error will decrease from 3 Hz to 0.5 Hz when the time of coherent processing is extended from 200 ms to 600 ms. Moreover, compared with the traditional FFT method, the proposed method’s computations of addition and multiplication are reduced by 96.2% and 35% respectively. The test results show that this algorithm is effective and superiority.