| 摘要: |
| 星载非相干扩频应答机在接收非相干扩频信号时，特别是在低信噪比条件下，信号跟踪环路中积分结果会因比特翻转而衰减严重，从而影响跟踪环路性能。针对上述问题，提出了一种HPK-P(Half-period Kokkonen-Pietila)位同步捕获法，将位同步时钟捕获精度缩短至半个伪码周期长，降低积分值衰减量，提高了跟踪前期的环路性能。仿真结果表明，与K-P法、半周期直方图法相比，〩PK-P法更适合-24 dB低信噪比下的环路跟踪。在现场可编程门阵列（Field Programmable Gate Array，FPGA）上对HPK-P法进行测试，在信噪比为-24 dB，多普勒频偏范围为±1.5 kHz，多普勒加速度为+2.5 kHz/s条件下验证了该设计的可行性。 |
| 关键词: 非相干扩频 信号跟踪 HPK-P 位同步 |
| DOI：10.20079/j.issn.1001-893x.230207005 |
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| 基金项目:国家重点研发计划（2021YFC2800203） |
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| A Half-period Kokkonen-Pietila(HPK-P) Bit Synchronization Capture Method for Incoherent Spread Spectrum Signal Tracking |
| HU Yihao,LIU Cairui,WANG Jinyang,ZENG Yanwen,LIANG Xianfeng |
| (1.National Space Science Center,Chinese Academy of Sciences,Beijing 100190,China;2.School of Electronic,Electrical and Communication Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;3.College of Physical Science and Technology,Central China Normal University,Wuhan 430079,China) |
| Abstract: |
| When receiving non-coherent spread spectrum signals,especially under low signal-to-noise ratio(SNR) conditions,the integration results in the signal tracking of the spaceborne non-coherent spread spectrum responders will decay severely due to bit flipping,which affects the performance of the tracking loop.To solve the above problem,a Half-period Kokkonen-Pietila(HPK-P) bit synchronization capture method is proposed,which shortens the bit synchronization clock capture accuracy to half a length of pseudocode period,reduces the attenuation of the integration value and improves the performance in the early stage of the tracking loop.Through simulation,the HPK-P method is compared with the K-P method and half-period histogram method,and the results show that HPK-P method is more suitable for loop tracking under the SNR of -24 dB.The feasibility of this design has been verified on field programmable gate array(FPGA) by testing HPK-P method under the conditions of Doppler range of ±1.5 kHz and Doppler acceleration of ±2.5 kHz/s when the SNR is -24 dB. |
| Key words: incoherent spread spectrum signal tracking HPK-P bit synchronization |
