scholarly journals The effects of using variable lengths for degraded signal acquisition in GPS receivers

2021 ◽  
Vol 11 (4) ◽  
pp. 3201
Author(s):  
Arif Hussain ◽  
Hina Magsi ◽  
Arslan Ahmed ◽  
Hadi Hussain ◽  
Zahid Hussain Khand ◽  
...  
Keyword(s):  
Acquisition Time ◽  
Signal Acquisition ◽  
Gps Receivers ◽  
Satellite Visibility ◽  
Accurate Position ◽  
Satellite Signal ◽  
Nlos Reception ◽  
Navigation Signals ◽  
Position Solution ◽  
Computation Load

The signal acquisition in GPS receivers is the first and very crucial process that may affect the overall performance of a navigation receiver. Acquisition program initiates a searching operation on received navigation signals to detect and identify the visible satellites. However, signal acquisition becomes a very challenging task in a degraded environment (i.e, dense urban) and the receiver may not be able to detect the satellites present in radio-vicinity, thus cannot estimate an accurate position solution. In such environments, satellite signals are attenuated and fluctuated due to fading introduced by Multipath and NLOS reception. To perform signal acquisition in such degraded environments, larger data accumulation can be effective in enhancing SNR, which tradeoff huge computational load, prolonged acquisition time and high cost of receiver. This paper highlights the effects of fading on satellite signal acquisition in GPS receiver through variable data lengths and SNR comparison, and then develops a statistical relationship between satellite visibility and SNR. Furthermore it also analyzes/investigates the tradeoff between computation load and signal data length.

ROBUST GPS SATELLITE SIGNAL ACQUISITION USING WAVELET

2005 ◽  
Vol 03 (04) ◽  
pp. 453-463 ◽  
Author(s):  
MOHAMED DJEBBOURI ◽  
DJAMEL DJEBOURI
Keyword(s):  
Global Positioning System ◽  
Additive Noise ◽  
Signal Acquisition ◽  
Positioning System ◽  
Gps Receivers ◽  
Global Positioning ◽  
Satellite Signal

In Global Positioning System (GPS), receivers use FFT-based convolvers to acquire the signals. This paper shows a robust substitute algorithm for calculating the convolution that is less sensitive to additive noise.

A New Robust GPS Satellite Signal Acquisition Using Lifting Wavelet

2005 ◽  
Vol 63 (5) ◽  
pp. 389-403 ◽  
Author(s):  
D. Djebouri ◽  
A. Djebbari ◽  
M. Djebbouri
Keyword(s):  
Signal Acquisition ◽  
Satellite Signal ◽  
Lifting Wavelet

Performance Analysis of Signal Acquisition in L2C Assisted GPS Receivers

2011 ◽  
Vol 17 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Seung-Hun Song ◽  
Ji-Won Park ◽  
Ji-Hee Park ◽  
Tae-Kyung Sung
Keyword(s):  
Performance Analysis ◽  
Signal Acquisition ◽  
Gps Receivers ◽  
Assisted Gps

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 Parametric Design Method for Optimal Quick Diagnostic Software

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 910
Author(s):  
Xiao-jian Yi ◽  
Peng Hou
Keyword(s):  
Response Time ◽  
Parametric Design ◽  
Design Method ◽  
Feature Selection Method ◽  
Acquisition Time ◽  
Signal Acquisition ◽  
Time Model ◽  
Vibration Data ◽  
Fault Diagnostic ◽  
Diagnostic Software

Fault diagnostic software is required to respond to faults as early as possible in time-critical applications. However, the existing methods based on early diagnosis are not adequate. First, there is no common standard to quantify the response time of a fault diagnostic software to the fault. Second, none of these methods take into account how the objective to improve the response time may affect the accuracy of the designed fault diagnostic software. In this work, a measure of the response time is provided, which was formulated using the time complexity of the algorithm and the signal acquisition time. Model optimization was built into the designed method. Its objective was to minimize the response time. The constraint of the method is to guarantee diagnostic accuracy to no less than the required accuracy. An improved feature selection method was used to solve the optimization modeling. After that, the design parameter of the optimal quick diagnostic software was obtained. Finally, the parametric design method was evaluated with two sets of experiments based on real-world bearing vibration data. The results demonstrated that optimal quick diagnostic software with a pre-defined accuracy could be obtained through the parametric design method.

scholarly journals A Fine Fast Acquisition Scheme for a Communication and Navigation Fusion System

2020 ◽  
Vol 10 (10) ◽  
pp. 3434
Author(s):  
Zhongliang Deng ◽  
Buyun Jia ◽  
Shihao Tang ◽  
Xiao Fu
Keyword(s):  
Search Space ◽  
Detection Performance ◽  
Acquisition Time ◽  
Signal Acquisition ◽  
Fusion System ◽  
Space Reduction ◽  
Fast Acquisition ◽  
Fast Processing ◽  
Detection Stage ◽  
Acquisition Method

A novel communication and navigation fusion system (CNFS) based on cellular communication system is developed to realize high-accuracy localization. Because of the small signal coverage of every transmitter and the fluctuation of received signal and noise, the CNFS positioning receiver requires fast processing of signal and stable performance. As the first operation performed by receiver, signal acquisition with fast speed and stable detection performance should be realized. This paper proposed a novel fast acquisition method with fine detection performance using search space reduction (SSR) and DD-MAX/TC-CACFAR techniques. SSR method is utilized to reduce the size and number of search space in the cross ambiguity function (CAF) evaluation stage. DD-MAX/TC-CACFAR method is employed to realize fine and stable detection performance in signal detection stage. The expressions of acquisition time are then derived considering the size and number of search space and the detection performance. Theoretical performance analysis and Monte Carlo simulation, which contain the comparison with other acquisition method, are presented to demonstrate the effectiveness of proposed method. Simulation and analysis results show that the proposed method can realize fast acquisition with fine and stable detection performance.

scholarly journals An Examination of Five Identical Mapping-Grade Global Positioning System Receivers in Two Forest Settings

2011 ◽  
Vol 26 (3) ◽  
pp. 119-125 ◽  
Author(s):  
Michael G. Wing ◽  
Jereme Frank
Keyword(s):  
Measurement Errors ◽  
Primary Objective ◽  
Average Error ◽  
Gps Receivers ◽  
Young Forest ◽  
Significant Difference ◽  
Secondary Objective ◽  
Satellite Signal ◽  
Sky Conditions ◽  
Identical Mapping

Abstract We collected measurements using five identical high-quality mapping-grade GPS receivers that were configured the same and collected data simultaneously in two distinctly different settings within a forest. Our primary objective was to determine whether measurement accuracies were different among the mapping-grade GPS receivers. A secondary objective was to determine whether measurement accuracies were different depending on whether receivers established their locations by taking a single 1-second measurement or by averaging 30 or 60 measurements. In the open-sky setting, where receivers had few obstructions overhead, we found that all five receivers recorded measurements with similar positional accuracies. Errors were lower when measurements were differentially corrected (postprocessed). We found an average error of 1.6 m for unprocessed data and an average error of 0.2 m for postprocessed data. Our results indicate that in open-sky conditions, all five receivers performed similarly when measurements were postprocessed. In addition, there was no significant difference in accuracy whether 1, 30, or 60 points were averaged, regardless of whether data were postprocessed. In the young-forest test course, examination of errors between receivers revealed that one receiver had significantly different errors compared with other receivers, which was likely the result of environmental influences on satellite signal strength and availability. We also found that measurement errors for all five receivers were significantly lower when measurements were postprocessed. On average, measurement errors were 5.9 m for unprocessed data and 1.4 m for postprocessed data. In analyzing individual receiver errors, no receiver had significantly different measurement errors whether 1, 30, or 60 measurements were recorded.

Tomographic Approach For Tropospheric Water Vapor Detection

2008 ◽  
Vol 8 (3) ◽  
pp. 263-278 ◽  
Author(s):  
P. MIIDLA ◽  
K. RANNAT ◽  
P. UBA
Keyword(s):  
Water Vapor ◽  
Large Scale ◽  
Prediction Models ◽  
Weather Prediction ◽  
Geographical Location ◽  
Vapor Detection ◽  
Gps Receivers ◽  
Cost Efficient ◽  
Effective Network ◽  
Navigation Signals

AbstractThe technical successes in radio navigation and the availability of nu-merical algorithms have promoted the implementation of GPS-technology to atmo-spheric sciences. The tomographical contribution of Global Satellite Navigation Sys-tems (GNSS) is possible due to the methods of high precision detection of tropospheric delays of navigation signals from satellites to receivers. The principal specific char-acter in initial constraints, data collection and assimilation methods, the obtaining of final numerical results and their interpretation make the continuation of the success story for GPS-tomography very challenging. The authors use numerical simulation as the most time- and cost-efficient way to study different processes related to tro-pospheric water vapor tomography. This paper tends to give a short overview about some known methods in GPS-tomography for detection, monitoring and modeling of the tropospheric water vapor. The possible mathematical approach to the construc-tion of virtual network of ground-based sensors (GPS-receivers) for a real geographical location and discretization of the troposphere, also some aspects of raw data filtering and analysis are described. Output of tomographical modelling of the troposphere can be used to improve the results of large-scale numerical weather prediction models and also real-time navigation. The questions of voxel geometry and methods of data processing are supposed to be the key questions in constructing an effective network of GPS-receivers for water vapor tomography.

Sign in / Sign up

Export Citation Format

Share Document