Print HE Zai-min1,2,3, HU Yong-hui1,2, WU Jian-feng1,2,3, MA Hong-jiao1,
WANG Ji-gang1,3, WANG Kang1,2,3
(1. National Time Service Centre, Chinese Academy of Sciences, Xi′an 710600, China;
2. Key Laboratory of Precision Navigation and Timing of Technology Chinese Academy of Sciences, Xi′an 710600, China;
3. Graduate University of Chinese Academy of Sciences, Beijing 100039, China)
Abstract: The relationship between the autocorrelation function of BOC signal and the radio-frequency front-end bandwidth is analyzed, and the influence of radio-frequency front-end bandwidth and spacing between early code and late code on the S curve is studied. Under the canonical model framework of TOA error estimation and with the no-coherent delay lock loop, a quantitative formula which relates the theoretically calculated code tracking error to the RF front-end bandwidth, spacing between early code and late code, carrier to noise ratio, integration time and code loop bandwidth, is derived leading to a quantitative analysis of the code tracking error for non-coherent delay lock loop. Finally, a comparison between the code tracking performance of BPSK-R signal and that of BOC(10,5) signal is made. The comparison shows that the BOC(10,5) signal code tracking performance is indeed superior to that of the traditional BPSK-R signal, and that to achieve the same code tracking accuracy, the required carrier to noise ratio for BOC(10,5) signal is ～7 dB lower than that for 10.23 MHz BPSK-R signal and～15 dB lower than that for 1.023 MHz BPSK-R signal.
Key words: BPSK-R signal; BOC signal; code tracking loop; S curve; autocorrelation function