In this paper, we propose an efficient scheme for side peak cancelation in binary offset carrier (m,n) (BOC(m,n)) with integer modulation order. The proposed scheme reduces significantly the width of the main peak of the auto-correlation function (ACF) and thus the range of influence of the multipath (MP) in BOC-modulated signals. It is based on the use of reference ACFs like that of ideal pseudo random noise (PRN) code generated by linear feedback shift register (LFSR) and used in global positioning system (GPS) and the Russian Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS). In MP environment, the proposed method is used in combination with fast iterative maximum likelihood algorithm (FIMLA) that is adapted to future modernized GPS and Galileo signals. As a result, the obtained ACF of the proposed scheme does not contain any side peaks, and thus, the discriminator function (DF) has no ambiguity in the delay-locked loop (DLL) code tracking operation. The simulation results show that the proposed technique has superior performances in MP mitigation and permits the same resistance to noise compared to the traditional techniques.

We propose an efficient scheme for side peaks cancelation and multipath (MP) mitigation in binary offset carrier (n,n) (BOC(n,n)) and multiplexed BOC (MBOC) modulated signals. The proposed scheme reduces significantly the band of variation of MP errors in global navigation satellite system (GNSS). It consists of two versions. The first one is based on the use of maximum likelihood estimator (MLE) of MP signals and reference correlation functions (CFs) like that of pseudorandom noise (PRN) code without BOC subcarrier. In the second version, the former (MLE) is used with the reference BOC(n,n) or MBOC CFs. Unlike traditional BOC(n,n) and MBOC, that have CFs containing multiple peaks leading to potential tracking ambiguities, our proposed scheme does not contain any side peaks. In addition, all the MP signals with medium and long delays have no effect on the estimation of the pseudorange. On the other hand, all the methods proposed for mitigating MP in no-BOC scheme are practical for our scheme due to its CF which is similar to that of the PRN code. The computer simulation results show that the proposed scheme has superior performances in the reduction of the errors produced in the process of the delay estimation of line of sight (LOS) and caused by MP propagation. In fact, the performances of the proposed scheme are better with regard to that of the traditional BOC(n,n) and MBOC. Moreover, in the presence of noise, our proposed scheme keeps better performances than the common side peaks cancelation methods.

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We propose a simpler and faster Gold codes generator, which can be efficiently initialized to any desired code, with a minimum delay. Its principle consists of generating only one sequence (code number 1) from which we can produce all the other different signal codes. This is realized by simply shifting this sequence by different delays that are judiciously determined by using the bicorrelation function characteristics. This is in contrast to the classical Linear Feedback Shift Register (LFSR) based Gold codes generator that requires, in addition to the shift process, a significant number of logic XOR gates and a phase selector to change the code. The presence of all these logic XOR gates in classical LFSR based Gold codes generator provokes the consumption of an additional time in the generation and acquisition processes. In addition to its simplicity and its rapidity, the proposed architecture, due to the total absence of XOR gates, has fewer resources than the conventional Gold generator and can thus be produced at lower cost. The Digital Signal Processing (DSP) implementations have shown that the proposed architecture presents a solution for acquiring Global Positioning System (GPS) satellites signals optimally and in a parallel way.

In this study, the authors propose reliable sequences of binary coded symbol (BCS) modulation, and their characteristics and performances for Global Navigation Satellite System (GNSS) application are described. A BCS sequence vector is formed by eight variable length sub-chips of alternated + 1 and −1 (or −1 and + 1) values. A judicious choice of the subchips lengths of the BCS sequence permitted to propose several BCS sequences that provide high performances in terms of multipath mitigation, resistance to the noise and interferences rejection. An overview of the essential characteristics and the resulting autocorrelation functions (ACFs) and power spectral densities of the proposed BCS sequences were introduced. The latter ACFs have a sharp main peak due to the increase in the number of transitions of the BCS sequences within a chip interval, which corresponds to a larger slope of the discrimination function, and consequently a reduced range of search in the delay locked loop with a minimum calculation load. The theoretical and simulation results indicate that the proposed BCS sequences are more consistent compared to the conventional signals adopted by the GNSS navigation systems.