GPS Weak-Signal BOC Code Acquisition

Brian McLemore and Mark L. Psiaki

Abstract:	Fast Fourier Transform (FFT) based acquisition algorithms for weak-signal long binary offset carrier (BOC) codes are implemented on a digital signal processor (DSP), and the time to first acquisition (TTFA) of different algorithms is examined. Combining a weak signal with a long spreading code results in many computations and, therefore, a very large TTFA. Frequency domain techniques are implemented to reduce the TTFA of these BOC codes. Matlab has been used to test the techniques off-line. In order to determine a realistic TTFA, however, the different algorithms have also been implemented on a practical DSP that is optimized for signal processing functions. The TTFA on the DSP has been found to be larger than in Matlab. It is believed this is due to stalls caused by accessing slower memory external to DSP. While the DSP results are not as good as expected, the ability to acquire long BOC codes on a commercially available DSP in degraded signal environments through the use of different FFT algorithms and techniques is demonstrated.
Published in:	Proceedings of the 32nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2019) September 16 - 20, 2019 Hyatt Regency Miami Miami, Florida
Pages:	3985 - 3996
Cite this article:	McLemore, Brian, Psiaki, Mark L., "GPS Weak-Signal BOC Code Acquisition," Proceedings of the 32nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2019), Miami, Florida, September 2019, pp. 3985-3996. https://doi.org/10.33012/2019.17110
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