Averaging correlation for C/A code acquisition and tracking in frequency domain

Starzyk, Janusz A.; Zhu, Zhen

doi:10.1109/mwscas.2001.986334

Cited by 48 publications

(30 citation statements)

References 3 publications

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“…To use smaller FFTs, it is possible to perform a sum before the FFT in order to have one sample per chip [27], [28]. Since it is not possible to know where is the beginning of the chips, the process is repeated starting the sum at different phases.…”

Section: Case With Pre-averagingmentioning

confidence: 99%

Acquisition of modern GNSS signals using a modified parallel code-phase search architecture

2014

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The acquisition of global navigation satellite system signals can be performed using a fast Fourier transform (FFT). The FFT-based acquisition performs a circular correlation, and is thus sensitive to potential transitions between consecutive periods of the code. Such transitions are not occurring often for the GPS L1 C/A signal because of the low data rate, but very likely for the new GNSS signals having a secondary code. The straightforward solution consists in using two periods of the incoming primary code and using zeropadding for the local code to perform the correlation. However, this solution increases the complexity, and is moreover not efficient since half of the points calculated are discarded. This has led us to research for a more efficient algorithm, which discards less points by calculating several sub-correlations.It is applied to the GPS L5, Galileo E5a, E5b and E1 signals. Considering the radix-2 FFT, the proposed algorithm is more efficient for the L5, E5a and E5b signals, and possibly for the E1 signal. The theoretical number of operations can be reduced by 21 %, the processing time measured on a * Corresponding author Email address: jerome.leclere@epfl.ch (Jérôme Leclère)Preprint submitted to Signal Processing July 2, 2013 software implementation is reduced by 39 %, and the memory resources are almost halved for an FPGA implementation.

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Section: Case With Pre-averagingmentioning

confidence: 99%

Acquisition of modern GNSS signals using a modified parallel code-phase search architecture

2014

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“…This of course increases the complexity of the FFT. This problem can also be solved by other means, including performing a traditional sample rate conversion [17], using GNSS specific signal compression algorithms [18,19], or using other FFT algorithms that can be applied to sequences whose length is not a power of two [20]. However, these algorithms are typically more difficult to implement.…”

Section: ) Parallel Code-phase Searchmentioning

confidence: 99%

“…This problem can be circumvented by using a smaller FFT with the overlap-and-add technique [14], performing decimation [17], or using a signal compression algorithm [18,19]. In this paper, we consider sampling frequencies for which the number of samples per code period is a power of two, and no signal decimation or compression.…”

Section: ) Parallel Code-phase Searchmentioning

confidence: 99%

Comparison Framework of FPGA-Based GNSS Signals Acquisition Architectures

Leclère

Botteron

Farine

2013

IEEE Trans. Aerosp. Electron. Syst.

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Abstract-The acquisition of Global Navigation Satellite Systems signals using Code Division Multiple Access can be performed through classical correlation or using a Fourier transform. These methods are well known but what is missing is a comparison of their performance for a given hardware area or target. This paper presents this comparison for FieldProgrammable Gate Arrays, describing the different parameters involved in the acquisition, detailing some optimized implementations where hardware elements are duplicated, and estimating and discussing the performances. The influence of the Doppler effect on the code, is also discussed as it plays an important role, particularly for new signals using a high chipping rate.

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“…For example, a method performs an average in order to obtain one sample per chip [18]. The proposed algorithm can be used in addition to such method.…”

Section: General Casementioning

confidence: 99%

Modified parallel code-phase search for acquisition in presence of sign transition

Leclère

Botteron

Farine

2013

2013 International Conference on Localization and GNSS (ICL-GNSS)

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Abstract-One of the method to have a fast acquisition of GNSS signals is the parallel code-phase search, which uses the fast Fourier transform (FFT) to perform the correlation. A problem with this method is the potential sign transition that can happen between two code periods due to data or secondary code and lead to a loss of sensitivity or to the non-detection of the signal. A known straightforward solution consists in using two code periods instead of one for the correlation. However, in addition to increasing the complexity, this solution is not efficient since half of the points calculated are discarded. This led us to look for a more efficient algorithm. The algorithm proposed in this article transforms the initial correlation into two smaller correlations. When the radix-2 FFT is used, the proposed algorithm is more efficient for half of the possible sampling frequencies. It is shown for example that the theoretical number of operations can be reduced by about 21 %, and that the memory resources for an FPGA implementation can be almost halved.

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Averaging correlation for C/A code acquisition and tracking in frequency domain

Cited by 48 publications

References 3 publications

Acquisition of modern GNSS signals using a modified parallel code-phase search architecture

Acquisition of modern GNSS signals using a modified parallel code-phase search architecture

Comparison Framework of FPGA-Based GNSS Signals Acquisition Architectures

Modified parallel code-phase search for acquisition in presence of sign transition

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