資源描述:
《GNSS接收機(jī)的一種快速捕獲方法研究.pdf》由會員上傳分享,免費(fèi)在線閱讀,更多相關(guān)內(nèi)容在行業(yè)資料-天天文庫。
1、第35卷第4期儀器儀表學(xué)報(bào)VoL35No.42014年4月ChineseJournalofScientificInstrumentApr.2014GNSS接收機(jī)的一種快速捕獲方法研究木鄭倫貴,尤政,張高飛,馬林,趙書敏(清華大學(xué)精密儀器系北京100084)摘要:動態(tài)環(huán)境中GNSS接收機(jī)與GNSS衛(wèi)星之間的高速徑向相對運(yùn)動導(dǎo)致GNSS信號產(chǎn)生多普勒頻移,為適應(yīng)信號多普勒頻移的大范圍變化盡快進(jìn)入跟蹤環(huán)節(jié),接收機(jī)需快速捕獲到載波多普勒頻移和偽碼相位并及時(shí)更新環(huán)路參數(shù)。針對傳統(tǒng)捕獲方法搜索時(shí)間長、捕獲困難的問題,基于信號時(shí)頻域特性提出
2、一種適用大范圍多普勒頻移、同時(shí)實(shí)現(xiàn)載波多普勒頻率和碼相位的快速捕獲方法并進(jìn)一步通過頻域相角確定載波精確多普勒頻率。仿真結(jié)果表明該方法捕獲時(shí)間為傳統(tǒng)捕獲的8%o,載波域捕獲法的36%,頻率分辨率為1OHz。該方法運(yùn)算量小、捕獲時(shí)間短,在保持高檢測概率情況下使捕獲結(jié)果滿足后續(xù)跟蹤環(huán)路要求。關(guān)鍵詞:GNSS接收機(jī);多普勒頻移;快速捕獲;分辨率中圖分類號:TN914.42文獻(xiàn)標(biāo)識碼:A國家標(biāo)準(zhǔn)學(xué)科分類代碼:590.35StudyonfastGNSSsignalacquisitioninGNSSreceiverZhengLungui,Y
3、ouZheng,ZhangGaofei,MaLin,ZhaoShumin(DepartmentofPrecisionm,nenf,TsinghuaUniversity,Beijing100084,China)Abstract:Inhighlydynamicenvironment,thehigh—speedradialrelativemotionbetweenGNSSreceiversandGNSSsat—ellitescausesDoppler~equencyshiftsoftheGNSSsignals.Inordertoad
4、aptthewiderangechangingoftheDopplerfrequencyshifts,theGNSSreceiversmustquicklyacquiretheDopplerfrequencyshiftandCAcodephase,andupdatetheloopparametersintime.Aimingattheproblemsoftraditionalacquisitionmethods,suchaslongsearchingtimeandacquisitiondifficulty,anewacquis
5、itionalgorithmisproposedbasedonthesignalcharacteristicsintimeand~equeneydomains,whichissuitableforwiderangechangingoftheDoppler~equencyshifts,andcanachievethefastacquisitionoftheDoppler~equencyshiftandCAcodephase;theproposedmethodcanachievethetwo—dimensionalandaccur
6、atecalculationofDopplerfrequencyfromthesignalphase.Theanalysisandsimulationresultshowsthattheacquisitiontimeis8%ofthatoftraditionalacquisitionmethodand36%ofthatofthecarrydomainacquisitionmethod;thefre—quencyresolutionis10Hz.Theproposedalgorithmhastheadvantagesofless
7、calculationandshortacquisitiontime,whichmeetsthetrackinglooprequirementofGNSSreceivers,whileretaininghighdetectionprobability.Keywords:GNSSreceiver;Doppler~equencyshift;fastacquisition;resolution當(dāng)前信號多普勒頻移和CA碼相位。高動態(tài)環(huán)境下除了1引言信號強(qiáng)弱外。],對捕獲速度影響最大的是GNSS接收機(jī)與衛(wèi)星之間高速徑向相對運(yùn)動產(chǎn)生的多普
8、勒頻移。在沒GNSS信號捕獲是接收機(jī)實(shí)現(xiàn)信號跟蹤和解調(diào)導(dǎo)航有外部先驗(yàn)信息條件下,接收機(jī)需在整個(gè)碼相位及大范電文及精確定位的前提條件,為使本地復(fù)制信號與接收圍多普勒頻帶內(nèi)搜索自身相對于每顆衛(wèi)星的多普勒頻率信號的差異進(jìn)入跟蹤環(huán)路的牽入范圍,接收機(jī)必須明確和碼相位。致使接收機(jī)耗費(fèi)很