scholarly journals Adaptive Data Length Method for GPS Signal Acquisition in Weak to Strong Fading Conditions

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1735
Author(s):  
Arif Hussain ◽  
Arslan Ahmed ◽  
Hina Magsi ◽  
Jahangeer Badar Soomro ◽  
Syed Sabir Hussain Bukhari ◽  
...  
Keyword(s):  
Power Level ◽  
Correlation Method ◽  
Threshold Level ◽  
Signal Acquisition ◽  
Indoor Environments ◽  
Navigation Systems ◽  
Signal Power ◽  
Shipping Industry ◽  
Acquisition Process ◽  
Data Length

Satellite-based navigation is an essential part of all the technology-dependent applications, such as road transport, cell phones, the medical field, aviation or the shipping industry, etc. The performance of the navigation systems depends upon how quickly they can acquire and process the received signals for positioning solutions. However, in dense urban or indoor environments, signal acquisition can be a challenging task due to fading as a result of multipath and/or interference. This paper presents post-processing acquisition results on Global Positioning System (GPS) signals to study the relationship between data lengths used for signal acquisition and the achieved signal power using a Fast Fourier Transform (FFT)-based circular correlation method. Based on this study, the detection performance of the FFT-based method has also been analyzed by intentionally degrading the signal power levels. A new Adaptive Data length (ADL) method for acquisition has been proposed in this paper, which can be used for speeding up the acquisition process and uses adaptive data lengths rather than fixed data lengths. The ADL method works by estimating the threshold level based on the noise present in the signal and then comparing it with the signal power levels. Less difference between the threshold level and signal power level means less data length will be used while more difference means that more data length will be used for acquisition. The proposed algorithm can be used in commercially available receivers for adopting to an adaptive acquisition process for increased efficiency.

scholarly journals GPS Signal Detection under Multiplicative and Additive Noise

2012 ◽  
Vol 66 (4) ◽  
pp. 479-500 ◽  
Author(s):  
P. Huang ◽  
Y. Pi ◽  
I. Progri
Keyword(s):  
Signal Detection ◽  
Urban Areas ◽  
Multiplicative Noise ◽  
Additive Noise ◽  
Power Level ◽  
Signal Propagation ◽  
Signal Acquisition ◽  
Detection Scheme ◽  
Additive And Multiplicative Noise ◽  
Gps Signal Acquisition

In some Global Positioning System (GPS) signal propagation environments, especially in the ionosphere and urban areas with heavy multipath, GPS signal encounters not only additive noise but also multiplicative noise. In this paper we compare and contrast the conventional GPS signal acquisition method which focuses on handling GPS signal acquisition with additive noise, with the enhanced GPS signal processing under multiplicative noise by proposing an extension of the GPS detection mechanism, to include the GPS detection model that explains detection of the GPS signal under additive and multiplicative noise. For this purpose, a novel GPS signal detection scheme based on high order cyclostationarity is proposed. The principle is introduced, the GPS signal detection structure is described, the ambiguity of initial PseudoRandom Noise (PRN) code phase and Doppler shift of GPS signal is analysed. From the simulation results, the received GPS signal at low power level, which is degraded by additive and multiplicative noise, can be detected under the condition that the received block of GPS data length is at least 1·6 ms and sampling frequency is at least 5 MHz.

scholarly journals Novel Point-to-Point Scan Matching Algorithm Based on Cross-Correlation

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Jaromir Konecny ◽  
Michal Prauzek ◽  
Pavel Kromer ◽  
Petr Musilek
Keyword(s):  
Cross Correlation ◽  
Traditional Approach ◽  
Correlation Method ◽  
Indoor Environments ◽  
Scan Matching ◽  
Computational Costs ◽  
Sensory Inputs ◽  
Special Cases ◽  
Mobile Robot Localization ◽  
Point To Point

The localization of mobile robots in outdoor and indoor environments is a complex issue. Many sophisticated approaches, based on various types of sensory inputs and different computational concepts, are used to accomplish this task. However, many of the most efficient methods for mobile robot localization suffer from high computational costs and/or the need for high resolution sensory inputs. Scan cross-correlation is a traditional approach that can be, in special cases, used to match temporally aligned scans of robot environment. This work proposes a set of novel modifications to the cross-correlation method that extend its capability beyond these special cases to general scan matching and mitigate its computational costs so that it is usable in practical settings. The properties and validity of the proposed approach are in this study illustrated on a number of computational experiments.

Fast Algorithm with Improved Circular Correlation Method for GPS Signal Acquisition

2013 ◽  
Vol 706-708 ◽  
pp. 794-797
Author(s):  
Yan Min Li ◽  
Qing Ming Yi ◽  
Min Shi
Keyword(s):  
Carrier Frequency ◽  
Fast Algorithm ◽  
Signal To Noise Ratio ◽  
Correlation Method ◽  
Signal Acquisition ◽  
Processing Efficiency ◽  
Coherent Integration ◽  
Circular Correlation ◽  
Acquisition Speed ◽  
Gps Signal Acquisition

In order to improve acquisition speed and carrier frequency accuracy, a fast algorithm to acquire GPS signal is proposed. Signal-to-Noise Ratio is improved by coherent integration and non-coherent integration. The advantages of serial sliding algorithm and circular correlation algorithm are combined to achieve high carrier frequency accuracy. Removing the information of C/A code makes serial search from two-dimensional to one-dimensional to achieve less computation. Simulation shows weak signal of-30dB S/N is successfully acquired. The error of carrier frequency is controlled within 50Hz. So the data processing efficiency for the tracking loop is greatly increased.

Weak GNSS Signal Acquisition for Indoor Environments

2018 ◽  
pp. 485-514
Author(s):  
Seung-Hyun Kong
Keyword(s):  
Signal Processing ◽  
State Of The Art ◽  
High Sensitivity ◽  
Urban Canyon ◽  
Signal Acquisition ◽  
Indoor Environments ◽  
Weak Signals ◽  
Fast Acquisition ◽  
Processing Techniques ◽  
Signal Processing Techniques

High sensitivity and fast acquisition are two important goals that must be considered in the development of signal processing techniques for a GNSS acquisition function to meet the demands for LBS in GNSS-challenged environments, such as indoor and urban canyon. This chapter introduces the fundamentals of GNSS acquisition functions, GNSS acquisition techniques for new GNSS signals, and GNSS acquisition techniques achieving high sensitivity and fast acquisition. Therefore, this chapter contains useful information for engineers who study the fundamentals and principles of GNSS acquisition and the state-of-the-art GNSS signal acquisition techniques for weak signals.

Mathematical Modelling of Indian Regional Navigation Satellite System Receiver

2017 ◽  
Vol 67 (4) ◽  
pp. 443 ◽  
Author(s):  
S. Naveen Pitchumani ◽  
S. Arun Sundar ◽  
T. Srinivasan ◽  
S. Savithri
Keyword(s):  
Navigation System ◽  
Satellite System ◽  
Signal Acquisition ◽  
Navigation Satellite ◽  
Navigation Systems ◽  
Code Tracking ◽  
Delay Locked Loop ◽  
Gps Navigation ◽  
Interface Control ◽  
Global Positioning

<p class="p1">At present the armoured fighting vehicles are equipped with either global positioning system (GPS) receivers or integrated inertial navigation system (INS)/GPS navigation systems. During hostile situations, the denial/degradation of the GPS satellite signals may happen. This results in the requirement of an indigenous satellite based navigation system. Indian Space Research Organisation has developed an indigenous Indian regional navigation satellite system (IRNSS), with a seven satellite constellation to provide independent position, navigation and timing services over India and its neighbouring regions. In this paper, the development of IRNSS receiver using MATLAB as per IRNSS signal in space interface control document for standard positioning service is discussed. A method for faster IRNSS signal acquisition in frequency domain and delay locked loop code tracking for the acquired satellite signals are used. Models for navigation message decoding and pseudo range/user position calculations are developed using the algorithms provided in IRNSS ICD.</p>

Research on Channel Equipment Reliability Analysis Methods of Measurement and Control System of Ship-Borne

2013 ◽  
Vol 765-767 ◽  
pp. 2057-2060
Author(s):  
Si Fang Liu ◽  
Jiu Lin Guo ◽  
Jian Hong Xu ◽  
Hong Qiang Guo
Keyword(s):  
Control System ◽  
Power Level ◽  
Signal Power ◽  
Test Results ◽  
Mathematical Methods ◽  
Measurement And Control System ◽  
Equipment Reliability ◽  
And Control ◽  
Measurement And Control ◽  
Methods Of Measurement

Aiming at the feature of failure occurs frequently, check links, difficult to position for channel equipment of measurement and control system of the ship-borne, according as to equipment index that reflects equipment performance-signal power level, analyzes channel equipment reliability by different mathematical methods, and based on the previous equipment test results of data analysis, presents the method of wavelet neural network, to analyze equipment reliability and forecast malfunction .

Based on Block Averaging Pre-Processing Differential Coherent Integration Weak Signal Acquisition Algorithm

2013 ◽  
Vol 706-708 ◽  
pp. 663-666
Author(s):  
Zhao Dong ◽  
Jing Shuo Niu ◽  
Ming He Feng ◽  
Xuan Ru Tao
Keyword(s):  
Monte Carlo Simulation ◽  
Signal Acquisition ◽  
Weak Signal ◽  
Signal Attenuation ◽  
Simulation Experiments ◽  
Coherent Integration ◽  
Coherent Accumulation ◽  
Interference Signals ◽  
The Stability ◽  
Data Length

Aiming at the problem of signal attenuation seriously, a block averaging pre-processing (BAP) differential coherent acquisition algorithm is proposed. BAP algorithm can be used to suppress interference signals and improve the stability of the receiver, but it is still faced with navigation signal transitions problem. Differential coherent algorithm can compensate for square loss caused by non-coherent accumulation. Monte Carlo simulation experiments show that the algorithm is more effective in the same carrier-to-noise ratio and same data length conditions.

scholarly journals INDOOR LIDAR RELOCALIZATION BASED ON DEEP LEARNING USING A 3D MODEL

2020 ◽  
Vol XLIII-B1-2020 ◽  
pp. 541-547
Author(s):  
H. Zhao ◽  
D. Acharya ◽  
M. Tomko ◽  
K. Khoshelham
Keyword(s):  
Indoor Environment ◽  
3D Model ◽  
Indoor Localization ◽  
High Accuracy ◽  
Lidar Data ◽  
Indoor Environments ◽  
Navigation Systems ◽  
Range Image ◽  
Range Images ◽  
Mapping Systems

Abstract. Indoor localization, navigation and mapping systems highly rely on the initial sensor pose information to achieve a high accuracy. Most existing indoor mapping and navigation systems cannot initialize the sensor poses automatically and consequently these systems cannot perform relocalization and recover from a pose estimation failure. For most indoor environments, a map or a 3D model is often available, and can provide useful information for relocalization. This paper presents a novel relocalization method for lidar sensors in indoor environments to estimate the initial lidar pose using a CNN pose regression network trained using a 3D model. A set of synthetic lidar frames are generated from the 3D model with known poses. Each lidar range image is a one-channel range image, used to train the CNN pose regression network from scratch to predict the initial sensor location and orientation. The CNN regression network trained by synthetic range images is used to estimate the poses of the lidar using real range images captured in the indoor environment. The results show that the proposed CNN regression network can learn from synthetic lidar data and estimate the pose of real lidar data with an accuracy of 1.9 m and 8.7 degrees.

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