摘要
提出了一种新的基于快速傅里叶变换(FFT)的P码直捕方法,并采用TS201对其进行了具体实现.该方法采用时间分格将大的P码时间不确定度分割成若干小的时间分格,并配合外部存储器的使用,有效减少了直捕过程中FFT的次数,并且可实现各种灵活的捕获策略.分析了低信噪比下非相参积累后的捕获概率及虚警概率,提出了基于两次检测的"A+B"检测方法,既保证了检测性能,又降低了捕获时间.性能分析结果显示,该方法能够在60 s内完成捕获信噪比为-32 dB,时间不确定度为±1 s的P码直捕.
A new direct P-code acquisition method based on FFT is proposed. The main concept of this method is to divide the large time uncertainty into several small time bins. It can greatly reduce the amount of FFT by cooperating with the use of external memory and thus to realize various acquisition policy flexibly. The probability of detection and false alarm of non-coherent integration under low SNR are analyzed, a new detection method called "A+B" based on double detection is presented. Thus not only the performance of detection is achieved, but also the acquisition time is saved. The implementation of this method using ADSP-TS201 is provided. It is shown that direct P-code acquisition can be accomplished within 60 s when the ratio of the signal and noise is -32 dB and the time uncertainty is ±1 s.
出处
《北京理工大学学报》
EI
CAS
CSCD
北大核心
2010年第3期326-330,339,共6页
Transactions of Beijing Institute of Technology