Informatics Publishing Limited

S. Mariappan ¹, G. Sasibhusana Rao ¹, Swarna Ravindrababu ², S. Sinthuja ³, S. Rajesh ⁴

Affiliations
1 Department of Electronics and Communication, AU College of Engineering, Visakhapatnam - 530003, Andhra Pradesh, IN
2 Samsung India, Bangalore – 560037, Karnataka, IN
3 Department of Tejas Research Centre of Excellence, AMET University, Chennai - 603112, Tamil Nadu, IN
4 Department of Electronics and Communication Engineering, Bharath University, Chennai - 600020, Tamil Nadu, IN

Abstract

The acquisition of GNSS signal is the most challenging part of any GNSS receiver. With the modernized GNSS system having longer code length and wider bandwidth, the size of the data block becomes large. To reduce the computational load of the processor, the reduction in the size of the data block without compromise in the acquisition loop performance provides overall improvement to the system. Here, a model is developed for acquisition of GPS signal L1 and L2C by compressing the input raw GPS signal with sequences of perfect periodic autocorrelation properties such as the Ipatov sequence. A compression matrix of the required dimension is constructed for compressing the input GPS signal. The improvement in the acquisition performance of the model is discussed.

Keywords

Acquisition, Compression, GPS, L2C, Modernised GPS

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S. Mariappan ¹, G. Sasibhusana Rao ¹, Swarna Ravindra Babu ²

Affiliations
1 AU College of Engineering, Andhra University, Visakhapatnam, Andhra Pradesh, IN
2 Samsung India, Bangalore, IN

Abstract

The acquisition and tracking of the GPS signals are the important and most challenging function in modernised GNSS receivers. In this paper this is addressed for the modernized GPS L2C signal. As an important pre-requisite, the characteristics of the modernised GPS L2C signals are presented. The correlation performance of the L2C codes is discussed. The generation of local GPS signal (the L2C code) required for the correlation during the acquisition as well as tracking is presented. Selection of some of the important variable parameters which contribute to the acquisition loop performance during acquisition is carried out. Various methods of the acquisition of the GPS L2C signals based on the linear correlation in time domain and the circular correlation in frequency domain are presented The tracking of the modernised GPS L2C signal based on the Costas PLL and the Delay Locked Loop (DLL) are presented. The acquisition and tracking of the GPS L2C signal with the assistance from the L1 C/A code signal acquisition is also presented.

Keywords

Acquisition, Correlation, GPS, L1 Assisted L2C, L2C, Modernised GPS, Tracking.

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