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1、第54卷第5期電訊技術(shù)Vo1.54No.52014年5月TelecommunicationEngineeringMav2014doi:10.3969/j.issn.1001—893x.2014.05.005引用格式:趙睿,王彥文.低信噪比條件下快變多普勒頻偏捕獲算法[J].電訊技術(shù),2014,54(5):553-558.[ZHAORui,WANGYan—wen.AFastChangingDopplerFrequencyOffsetAcquisitionAlgorithmunderLowSNR[J].TelEngineering,2014,54(5):553-558.]低信噪比
2、條件下快變多普勒頻偏捕獲算法趙睿料,王彥文(中國(guó)礦業(yè)大學(xué)(北京)機(jī)電與信息工程學(xué)院,北京100091)摘要:針對(duì)衛(wèi)星移動(dòng)通信低信噪比條件下快變多普勒頻偏捕獲提出了一種新的算法即基于搜索空間壓縮的譜線循環(huán)平移算法。首先,介紹了現(xiàn)有的載波頻偏捕獲技術(shù),分析其不能適應(yīng)快變多普勒頻偏條件的原因;其次,分析了多普勒變化率對(duì)載波頻偏捕獲的影響,主要考慮一次變化率與二次變化率將嚴(yán)重限制低信噪比情況下對(duì)載波頻偏估計(jì)時(shí)非相干累加的有效性;最后,在此基礎(chǔ)上,提出了低信噪比條件下快變多普勒頻偏捕獲的基于搜索空間壓縮的譜線循環(huán)平移算法。對(duì)算法進(jìn)行的Matlab仿真結(jié)果表明,其具有2~3dB的改善增益
3、,與最大似然算法相比,在性能僅有0.2dB損失的情況下運(yùn)算量大大減少。關(guān)鍵詞:低地球軌道星座;衛(wèi)星移動(dòng)通信;高動(dòng)態(tài)信號(hào);載波捕獲;快變多普勒頻偏;低信噪比中圖分類號(hào):TN911.72;TN914.42文獻(xiàn)標(biāo)志碼:A文章編號(hào):1001—893X(2014)05—0553-06AFastChangingDopplerFrequencyOfsetAcquisitionAlgorithmunderLowSNRZHAORui,WANGYan-wen(DepartmentofMechanicalElectrical&InformationEngineering,ChinaUniversi
4、tyofMining&Technology(Beijing),Beijing100091,China)Abstract:Anewalgorithmorthespectrumlinecircleshiftalgorithmbasedoncompressedsearchingspaceisproposedf_0rfastchangingDoppler~equencyoffsetacquisitionunderlowsignal—to—n0iseratio(SNR)forsatellitemobilecommunication.Firstly,currentcarrier~eque
5、ncyoffsetacquisitiontechnologiesarein—troduced,andthereasonwhythesetechnologiescannotadapttofastchangingDoppler~equencyoffsetac—quisitionisanalyzed.Then,theeffectofchangingrateofDoppler~equencyoffsetoncarrier~equencyoff-setacquisitionisanalyzed.Thesituationthatthefirstorderchangingrateandse
6、condorderchangingrateaffectcarrieracquisitionisconsideredemphatically.ThechangingrateofDoppler~equencyoffsetserious—lyreducestheeffectivenessofnon——coherentaccumulationduringcarrier~equencyoffsetestimationatlowSNR.Finally,onthisbase,thespectrumlinecircleshiftalgorithmbasedonthecompressedsea
7、rchingspaceisprovidedandsimulatedwithMatlab.Theresultshowsthatthealgorithmhasgainimprovementof2—3dB.Comparedwithmaximumlikelihood(ML),theproposedalgorithmlosses0.2dBperformance,however,amountofcalculationisgreatlyreduced.Keywords:lowearthorbitconstellati