CAJ | 학술논문

室外无人搬运车（automatic guided vehicle，AGV）运输和未来的无人驾驶智能汽车等对全球定位系统（global positioning system，GPS）高精度定位精度要求较高，GPS L1／L2C 双频信号可以校正电离层误差从而提高 GPS 单机的定位精度。但 L2C 民用中码／民用长码（civil moderate／civil long code，CM／CL）的长度远大于L1粗捕获码（coarse／acquisition code，C／A），传统的捕获算法直接用于 L2C 信号会使捕获时间延长甚至导致捕获失效。对此，提出了利用捕获到的 L1信号的多普勒频移和 C／A 码相位对 L2 CM 码进行辅助捕获，然后利用CM 码码相位对 CL 码进行辅助捕获的方法，减小了 L2C 信号捕获的二维搜索范围；同时在相关运算中利用分裂基快速傅里叶变换（split-radix fast Fourier transform，SFFT）代替传统的基2 FFT 进一步降低了计算量。仿真结果表明，所提算法在运算量明显降低的情况下可以实现对 L1／L2C 双频信号的精确捕获。
실외무인반운차（automatic guided vehicle，AGV）운수화미래적무인가사지능기차등대전구정위계통（global positioning system，GPS）고정도정위정도요구교고，GPS L1／L2C 쌍빈신호가이교정전리층오차종이제고 GPS 단궤적정위정도。단 L2C 민용중마／민용장마（civil moderate／civil long code，CM／CL）적장도원대우L1조포획마（coarse／acquisition code，C／A），전통적포획산법직접용우 L2C 신호회사포획시간연장심지도치포획실효。대차，제출료이용포획도적 L1신호적다보륵빈이화 C／A 마상위대 L2 CM 마진행보조포획，연후이용CM 마마상위대 CL 마진행보조포획적방법，감소료 L2C 신호포획적이유수색범위；동시재상관운산중이용분렬기쾌속부리협변환（split-radix fast Fourier transform，SFFT）대체전통적기2 FFT 진일보강저료계산량。방진결과표명，소제산법재운산량명현강저적정황하가이실현대 L1／L2C 쌍빈신호적정학포획。
Outdoor automatic guided vehicle (AGV)transportation and future intelligent unmanned vehicles require positioning accuracy high for the global positioning system (GPS),GPS L1/L2C dual-frequency signals can improve the location accuracy by correcting ionospheric delay.However,L2 civil moderate/civil long (CM/CL)codes are both much longer than L1 coarse/acquisition(C/A)codes.If the traditional acquisition algorithm is applied to L2C acquisition directly,it will lead to much longer acquisition time and even failed acquisition. Therefore,an algorithm is proposed,which accomplishes CM acquisition by using the acquired Doppler shift and C/A code phase of L1 signals,then similarly finishes CL acquisition by the CM aided code phase,which makes the two-dimension searching process for L2C acquisition narrow down to searching one dimension code phase with fewer discrete points.Meanwhile,the split-radix fast Fourier transform (SFFT)instead of tradi-tional radix-2 FFT is introduced into correlation operation,which can reduce the calculated quantity further. Simulation results show that the suggested algorithm can achieve accurate acquisition of dual-frequency signals with much lower calculated amount.