scholarly journals Band-Pass Sampling in High-Order BOC Signal Acquisition

2018 ◽  
Vol 8 (11) ◽  
pp. 2226 ◽  
Author(s):  
Zhijun Liu ◽  
Baiyu Li ◽  
Xiangwei Zhu ◽  
Lixun Li ◽  
Guangfu Sun
Keyword(s):  
Computational Complexity ◽  
Sampling Technique ◽  
Global Navigation Satellite Systems ◽  
Signal Acquisition ◽  
Binary Offset Carrier ◽  
Satellite Systems ◽  
Sampled Signal ◽  
Band Pass ◽  
Global Navigation Satellite ◽  
High Computational Complexity

The binary offset carrier (BOC) modulation, which has been adopted in modern global navigation satellite systems (GNSS), provides a higher spectral compatibility with BPSK signals, and better tracking performance. However, the autocorrelation function (ACF) of BOC signals has multiple peaks. This feature complicates the acquisition process, since a smaller time searching step is required, which results in longer searching time or greater amounts of hardware resources. Another problem is the high Nyquist frequency, which leads to high computational complexity and power consumption. In this paper, to overcome these drawbacks, the band-pass sampling technique for multiple signals is introduced to BOC signals. The sampling frequency can be reduced significantly. Furthermore, the ACF of the sampled signal has only two secondary peaks, so that the code phase can be searched with a larger searching step. An acquisition structure base on dual-loop is proposed, to completely eliminate the ambiguity and compensate the subcarrier Doppler. The acquisition performance and the computational complexity are also analysed.

scholarly journals Gnss Signal Processing in Gpu

2013 ◽  
Vol 48 (2) ◽  
pp. 51-61 ◽  
Author(s):  
Petr Roule ◽  
Ondřej Jakubov ◽  
Pavel Kovář ◽  
Petr Kařmařík ◽  
František Vejražka
Keyword(s):  
Signal Processing ◽  
Graphics Processing Units ◽  
Digital Signal ◽  
General Purpose ◽  
Global Navigation Satellite Systems ◽  
Acquisition Time ◽  
Signal Acquisition ◽  
Satellite Systems ◽  
Central Processing ◽  
Global Navigation Satellite

ABSTRACT Signal processing of the global navigation satellite systems (GNSS) is a computationally demanding task due to the wide bandwidth of the signals and their complicated modulation schemes. The classical GNSS receivers therefore utilize tailored digital signal processors (DSP) not being flexible in nature. Fortunately, the up-to-date parallel processors or graphical processing units (GPUs) dispose sufficient computational power for processing of not only relatively narrow band GPS L1 C/A signal but also the modernized GPS, GLONASS, Galileo and COMPASS signals. The performance improvement of the modern processors is based on the constantly increasing number of cores. This trend is evident not only from the development of the central processing units (CPUs), but also from the development of GPUs that are nowadays equipped with up to several hundreds of cores optimized for video signals. GPUs include special vector instructions that support implementation of massive parallelism. The new GPUs, named as general-purpose computation on graphics processing units (GPGPU), are able to process both graphic and general data, thus making the GNSS signal processing possible. Application programming interfaces (APIs) supporting GPU parallel processing have been developed and standardized. The most general one, Open Computing Language (Open CL), is now supported by most of the GPU vendors. Next, Compute Unified Device Architecture (CUDA) language was developed for NVidia graphic cards. The CUDA language features optimized signal processing libraries including efficient implementation of the fast Fourier transform (FFT). In this paper, we study the applicability of the GPU approach in GNSS signal acquisition. Two common parallel DSP methods, parallel code space search (PCSS) and double-block zero padding (DBZP), have been investigated. Implementations in the C language for CPU and the CUDA language for GPU are discussed and compared with respect to the acquisition time. It is shown that for signals with long ranging codes (with 10230 number of chips - Galileo E5, GPS L5 etc.). Paper presented at the "European Navigation Conference 2012", held in Gdansk, Poland

scholarly journals A New Acquisition Algorithm with Elimination Side Peak for All BOC Signals

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Fang Liu ◽  
Yongxin Feng
Keyword(s):  
Correlation Function ◽  
Global Navigation Satellite Systems ◽  
Navigation Satellite ◽  
Binary Offset Carrier ◽  
Side Peak ◽  
Acquisition Performance ◽  
Satellite Systems ◽  
Simulation Results ◽  
Global Navigation Satellite ◽  
Better Than

A new inhibition side peak acquisition (ISPA) algorithm is proposed for binary offset carrier (BOC) modulated signals, which will be utilized in global navigation satellite systems (GNSS). We eliminate all side peaks of the BOC correlation function (CF) by structuring special sequences composed of PRN code and cycle rectangular sequences. The new algorithm can be applied to both generic sine- and cosine-phased BOC signals, as well as to all modulation orders. Theoretical and simulation results demonstrate that the new algorithm can completely eliminate the ambiguity threat in the acquisition process, and it can adapt to lower SNR. In addition, this algorithm is better than the traditional algorithms in acquisition performance and inhibition side peak ability.

Bit Sign Transition Cancellation Method for GNSS Signal Acquisition

2011 ◽  
Vol 65 (1) ◽  
pp. 73-97 ◽  
Author(s):  
Kewen Sun ◽  
Letizia Lo Presti
Keyword(s):  
Doppler Shift ◽  
Signal To Noise Ratio ◽  
Search Space ◽  
Global Navigation Satellite Systems ◽  
Main Peak ◽  
Signal Acquisition ◽  
Satellite Systems ◽  
Gps Modernization ◽  
Improved Performance ◽  
Global Navigation Satellite

The next generation Global Navigation Satellite Systems (GNSS), such as Galileo and Global Positioning System (GPS) modernization, will use signals with equal code and bit periods, resulting in a potential bit sign transition in each primary code period of the received signal segments. A bit sign transition occurring within an integration period usually causes a splitting of the Cross Ambiguity Function (CAF) main peak into two smaller side lobes along the Doppler shift axis in the search space and it may lead to an incorrect Doppler shift estimate, which results in a serious performance degradation of the acquisition system. This paper proposes a novel two steps based bit sign transition cancellation method which can overcome the bit sign transition problem and remove or mitigate the CAF peak splitting impairments. The performance of the proposed technique has been comprehensively evaluated with Monte Carlo simulations in terms of detection and false alarm probabilities, which are presented by Receiver Operating Characteristic (ROC) and Signal-to-Noise-Ratio (SNR) curves. The test results show that the proposed acquisition technique can provide improved performance in comparison with the state-of-the-art acquisition approaches.

scholarly journals A Chip Scale Atomic Clock Driven Receiver for Multi-Constellation GNSS

2013 ◽  
Vol 66 (3) ◽  
pp. 449-464 ◽  
Author(s):  
Alper Ucar ◽  
Yacine Adane ◽  
Burak Bardak ◽  
Carlo Paparo ◽  
Reuben Berry ◽  
...  
Keyword(s):  
Rapid Development ◽  
Atomic Clock ◽  
Global Navigation Satellite Systems ◽  
Dual Band ◽  
Easy Access ◽  
Signal Acquisition ◽  
Multipath Mitigation ◽  
Satellite Systems ◽  
Dual Channel ◽  
Global Navigation Satellite

This paper presents the design and implementation of a Chip Scale Atomic Clock (CSAC) driven dual-channel Digitally Configurable Receiver (DCR) for Global Navigation Satellite Systems (GNSS). The receiver is intended to be used for research applications such as; multipath mitigation, scintillation assessment, advanced satellite clock and spatial frame transformation modelling, Precise Point Positioning (PPP) as well as rapid development and assessment of novel circuits and systems for GNSS receivers. A novel sub-Nyquist sampling (subsampling) receiver architecture incorporating dual-band microstrip RF filters is employed in order to minimize the complexity of the multi-frequency Radio Frequency (RF) front-end. Moreover, the digital receiver incorporates a novel and complexity-reduced Fast Fourier Transform (FFT) core for signal acquisition as well as COordinate Rotation DIgital Computer (CORDIC) cores for the code/carrier discriminators in order to minimize the resource allocation on the FPGA. The receiver also provides easy access to enable adjustment of its internal parameters such as; RF gain, position update rate, tracking channel correlator spacing and code/carrier loop noise bandwidth. Correlator outputs, code/carrier error, Carrier-to-Noise Ratio (C/N0), navigation and RINEX data are provided to the end-user in real-time. This paper collectively highlights and reports on the implementation, test and validation of the novel techniques, elements and approaches in both the RF and digital part of the DCR that comprise the multi-constellation receiver.

scholarly journals Data and Pilot Combining for Composite GNSS Signal Acquisition

2008 ◽  
Vol 2008 ◽  
pp. 1-12 ◽  
Author(s):  
Daniele Borio ◽  
Letizia Lo Presti
Keyword(s):  
Global Navigation Satellite Systems ◽  
Signal Acquisition ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Open Service ◽  
Global Navigation ◽  
Global Navigation Satellite ◽  
Coherent Combining

With the advent of new global navigation satellite systems (GNSS), such as the European Galileo, the Chinese Compass and the modernized GPS, the presence of new modulations allows the use of special techniques specifically tailored to acquire and track the new signals. Of particular interest are the new composite GNSS signals that will consist of two different components, the data and pilot channels. Two strategies for the joint acquisition of the data and pilot components are compared. The first technique, noncoherent combining, is from the literature and it is used as a comparison term, whereas the analysis of the second one, coherent combining with sign recovery, represents the innovative contribution of this paper. Although the analysis is developed with respect to the Galileo E1 Open Service (OS) modulation, the obtained results are general and can be applied to other GNSS signals.

A Multipath Cancellation Method Based on TK Operator for BOC Signals

2013 ◽  
Vol 680 ◽  
pp. 454-459
Author(s):  
Zhong Liang Deng ◽  
Lei Yang ◽  
Lu Yin ◽  
Yue Xi
Keyword(s):  
Global Navigation Satellite Systems ◽  
Binary Offset Carrier ◽  
Side Peak ◽  
Satellite Systems ◽  
Low Snr ◽  
Navigation Signals ◽  
Multipath Signals ◽  
Global Navigation Satellite ◽  
The Right ◽  
New Generation

The new generation of global navigation satellite systems will apply binary offset carrier (BOC) modulation technique, which can efficiently split the spectrums of navigation signals using the same frequency so as to reduce the interferences among different systems. But the autocorrelation function of BOC modulated signals has the drawback of multimodality, so it’s very hard to synchronize to the right peak when acquiring and tracking signals, especially under low SNR circumstances, which can decrease the positioning accuracy and even lead to wrong positioning results. Meanwhile, if there are multipath signals mixed in the receiving signal, the autocorrelation curve will be greatly distorted, and the number of side-peak will also increase exaggeratedly, which could deteriorate the situation mentioned above. A multipath cancellation method based on TK (Teager-Kaiser) operator is proposed in this article, which could not only detect the right peak in the autocorrelation curve, but also eliminate all the other multipath signals. As a result, this method could avoid the false lock of code phase and guarantee the high precision fix results.

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