scholarly journals GNSS/INS Fusion with Virtual Lever-Arm Measurements

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2228 ◽  
Author(s):  
Aviram Borko ◽  
Itzik Klein ◽  
Gilad Even-Tzur
Keyword(s):  
Field Experiments ◽  
Satellite System ◽  
Improve Performance ◽  
Lever Arm ◽  
Additional Improvement ◽  
Stationary Conditions ◽  
State Observability ◽  
Global Navigation Satellite ◽  
Navigation Accuracy ◽  
Improve State

The navigation subsystem in most platforms is based on an inertial navigation system (INS). Regardless of the INS grade, its navigation solution drifts in time. To avoid such a drift, the INS is fused with external sensor measurements such as a global navigation satellite system (GNSS). Recent publications showed that the lever-arm, defined as the relative position between the INS and aiding sensor, has a strong influence on navigation accuracy. Most research in this field is focused on INS/GNSS fusion with GNSS position or velocity updates while considering various maneuvers types. In this paper, we propose to employ virtual lever-arm (VLA) measurements to improve the accuracy and time to convergence of the observable INS error-states. In particular, we show that VLA measurements improve performance even in stationary conditions. In situations when maneuvering helps to improve state observability, VLA measurements manage to gain additional improvement in accuracy. These results are supported by simulation and field experiments with a vehicle mounted with a GNSS and an INS.

scholarly journals A Joint Dual-Frequency GNSS/SINS Deep-Coupled Navigation System for Polar Navigation

2018 ◽  
Vol 8 (11) ◽  
pp. 2322 ◽  
Author(s):  
Lin Zhao ◽  
Mouyan Wu ◽  
Jicheng Ding ◽  
Yingyao Kang
Keyword(s):  
Navigation System ◽  
Density Ratio ◽  
Satellite System ◽  
The Arctic ◽  
Observation Data ◽  
Dual Frequency ◽  
Vector Tracking ◽  
Time Observation ◽  
Global Navigation Satellite ◽  
Navigation Accuracy

The strategic position of the polar area and its rich natural resources are becoming increasingly important, while the northeast and northwest passages through the Arctic are receiving much attention as glaciers continue to melt. The global navigation satellite system (GNSS) can provide real-time observation data for the polar areas, but may suffer low elevation problems of satellites, signals with poor carrier-power-to-noise-density ratio (C/N0), ionospheric scintillations, and dynamic requirements. In order to improve the navigation performance in polar areas, a deep-coupled navigation system with dual-frequency GNSS and a grid strapdown inertial navigation system (SINS) is proposed in the paper. The coverage and visibility of the GNSS constellation in polar areas are briefly reviewed firstly. Then, the joint dual-frequency vector tracking architecture of GNSS is designed with the aid of grid SINS information, which can optimize the tracking band, sharing tracking information to aid weak signal channels with strong signal channels and meet the dynamic requirement to improve the accuracy and robustness of the system. Besides this, the ionosphere-free combination of global positioning system (GPS) L1 C/A and L2 signals is used in the proposed system to further reduce ionospheric influence. Finally, the performance of the system is tested using a hardware simulator and semiphysical experiments. Experimental results indicate that the proposed system can obtain a better navigation accuracy and robust performance in polar areas.

scholarly journals Results of the GNSS receiver experiment OCAM-G on Ariane-5 flight VA 219

2016 ◽  
Vol 231 (6) ◽  
pp. 1100-1114 ◽  
Author(s):  
André Hauschild ◽  
Markus Markgraf ◽  
Oliver Montenbruck ◽  
Horst Pfeuffer ◽  
Elie Dawidowicz ◽  
...  
Keyword(s):  
French Guiana ◽  
Satellite System ◽  
Navigation Satellite ◽  
Navigation Solution ◽  
Gnss Receiver ◽  
Upper Stage ◽  
Lift Off ◽  
Global Navigation Satellite ◽  
Navigation Accuracy ◽  
First Time

The fifth Automated Transfer Vehicle was launched on 29 July 2014 with Ariane-5 flight VA 219 into orbit from Kourou, French Guiana. For the first time, the ascent of an Ariane rocket was independently tracked with a Global Navigation Satellite System (GNSS) receiver on this flight. The GNSS receiver experiment OCAM-G was mounted on the upper stage of the rocket. Its receivers tracked the trajectory of the Ariane-5 from lift-off until after the separation of the Automated Transfer Vehicle. This article introduces the design of the experiment and presents an analysis of the data gathered during the flight with respect to the GNSS tracking status, availability of navigation solution, and navigation accuracy.

scholarly journals Evaluation on Nonholonomic Constraints and Rauch–Tung–Striebel Filter-Enhanced UWB/INS Integration

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Zhouzheng Gao ◽  
Lin Chen ◽  
Yu Min ◽  
Jie Lv ◽  
You Li
Keyword(s):  
Three Dimensional ◽  
Nonholonomic Constraints ◽  
Satellite System ◽  
Least Square ◽  
Precise Positioning ◽  
Global Navigation Satellite ◽  
Navigation Accuracy ◽  
The Impact ◽  
The Mathematical Model ◽  
Better Than

Precise and seamless positioning is becoming a basic requirement for the Internet of Things (IoT). However, there is a gap for precise positioning in Global Navigation Satellite System- (GNSS-) denied indoor areas. Thus, a multisensor integration system based on ultrawide-band (UWB), inertial navigation system (INS), nonholonomic constraints (NHCs), and Rauch–Tung–Striebel (RTS) smoother is proposed. In this system, the UWB performs as the major precise positioning system, while the INS bridges the UWB-degraded and UWB-denied periods. Meanwhile, the NHC restrains the drifts of INS, while the RTS smoother further upgrades the navigation accuracy. The contributions of this article are as follows. First, it presents the robust least square- (RLS-) based UWB positioning. The proposed method is effective in mitigating the impact of the effect of non-line-of-sight (NLOS), which is one of the most significant error sources for UWB positioning. Second, it derives the mathematical model of the UWB/INS/NHC/RTS integration, which is new compared to the existing approaches. Results illustrate that the proposed system can provide centimeter-level positioning accuracy, millimeter-level velocimetry accuracy, and accuracy of better than 0.05 and 0.15 degrees for horizontal and vertical attitude angles, respectively. Even in the scenario with short-term UWB outages (30 s), simulation results show that the three-dimensional position still can be better than 20 cm. Such accuracy values reach the state-of-the-art for indoor positioning using UWB and INS.

scholarly journals Calibração da Plataforma de um Sistema de Visão Omnidirecional composto por uma Câmara e um Espelho Cônico

2020 ◽  
Vol 72 (2) ◽  
pp. 270-279
Author(s):  
José Marcato Junior ◽  
Thales Shoiti Akiyama ◽  
Antonio Maria Garcia Tommaselli ◽  
Marcus Vinícius Antunes de Moraes ◽  
Vanessa Jordão Marcato Fernandes
Keyword(s):  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
Inertial Measurement ◽  
Lever Arm ◽  
Global Navigation ◽  
Global Navigation Satellite

Os sistemas de visão omnidirecional permitem um campo de imageamento de 360° e são aplicados em diversas áreas do conhecimento, incluindo a Fotogrametria à curta distância. Para obter medidas confiáveis, objetivo da Fotogrametria, exige-se a calibração do sistema, em que os parâmetros dos modelos matemáticos são estimados. A calibração do sistema é dividida em calibração interna e da plataforma. O objetivo principal desse trabalho consiste em realizar a calibração da plataforma de um sistema de visão omnidirecional composto por uma câmara e um espelho cônico. Na calibração da plataforma foram estimados os parâmetros que relacionam o sistema de imageamento com o sistema de georreferenciamento direto, composto por receptor GNSS (Global Navigation Satellite System – Sistema global de navegação por satélite) e IMU (Inertial Measurement Unity – Unidade de Medida Inercial). Estimaram-se os ângulos de desalinhamento (boresight) da IMU com relação ao referencial do cone e os deslocamentos (lever arm) do vértice do cone ao centro da antena GNSS. A incerteza na estimativa do lever arm é, no mínimo, 10 vezes menor que a precisão obtida com o receptor GNSS no modo cinemático, o que indica uma qualidade adequada para o valor estimado. Com relação aos ângulos de desalinhamento, a REQM (Raiz do Erro Quadrático Médio) foi maior para o ângulo de rotação

scholarly journals DME/DME AND VOR/DME POSITIONING ERRORS ESTIMATION

2018 ◽  
Vol 1 (47) ◽  
pp. 12-16
Author(s):  
I. V. Ostroumov
Keyword(s):  
Global Navigation Satellite System ◽  
Measuring Equipment ◽  
Satellite System ◽  
Navigation Satellite ◽  
Aircraft Flight ◽  
Positioning Errors ◽  
Civil Aircraft ◽  
Global Navigation Satellite ◽  
Navigation Accuracy ◽  
Errors Estimation

Currently, area navigation methods are used as alternative to Global Navigation Satellite System. The most popular alternative method of positioning is grounded on the usage of Distanse Measuring Equipment data in the algorithms of an aircraft Flight Management System. Estimation of aircraft position error is one of the most important tasks of navigation. An article considers the problem of positioning errors estimation by DME equipment. In accordance with the international requirements for the airborne equipment of civil aircraft, the problem is considered in terms of optimal DME pair usage. DME/DME and VOR/DME navigation accuracy for a pair of navigational aids is estimated.

scholarly journals A LSTM Algorithm Estimating Pseudo Measurements for Aiding INS during GNSS Signal Outages

2020 ◽  
Vol 12 (2) ◽  
pp. 256 ◽  
Author(s):  
Wei Fang ◽  
Jinguang Jiang ◽  
Shuangqiu Lu ◽  
Yilin Gong ◽  
Yifeng Tao ◽  
...  
Keyword(s):  
Neural Network ◽  
Short Term Memory ◽  
Satellite System ◽  
Test Results ◽  
Dynamic Information ◽  
Vehicle Data ◽  
Global Navigation Satellite ◽  
Almost All ◽  
Navigation Accuracy ◽  
Ins Aiding

Aiming to improve the navigation accuracy during global navigation satellite system (GNSS) outages, an algorithm based on long short-term memory (LSTM) is proposed for aiding inertial navigation system (INS). The LSTM algorithm is investigated to generate the pseudo GNSS position increment substituting the GNSS signal. Almost all existing INS aiding algorithms, like the multilayer perceptron neural network (MLP), are based on modeling INS errors and INS outputs ignoring the dependence of the past vehicle dynamic information resulting in poor navigation accuracy. Whereas LSTM is a kind of dynamic neural network constructing a relationship among the present and past information. Therefore, the LSTM algorithm is adopted to attain a more stable and reliable navigation solution during a period of GNSS outages. A set of actual vehicle data was used to verify the navigation accuracy of the proposed algorithm. During 180 s GNSS outages, the test results represent that the LSTM algorithm can enhance the navigation accuracy 95% compared with pure INS algorithm, and 50% of the MLP algorithm.

scholarly journals Improving Multisensor Positioning of Land Vehicles with Integrated Visual Odometry for Next-Generation Self-Driving Cars

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Muhammed Tahsin Rahman ◽  
Tashfeen Karamat ◽  
Sidney Givigi ◽  
Aboelmagd Noureldin
Keyword(s):  
Autonomous Vehicles ◽  
High Performance ◽  
Inertial Sensors ◽  
Low Cost ◽  
Visual Odometry ◽  
Satellite System ◽  
Land Vehicles ◽  
Self Driving Cars ◽  
Global Navigation Satellite ◽  
Navigation Accuracy

For their complete realization, autonomous vehicles (AVs) fundamentally rely on the Global Navigation Satellite System (GNSS) to provide positioning and navigation information. However, in area such as urban cores, parking lots, and under dense foliage, which are all commonly frequented by AVs, GNSS signals suffer from blockage, interference, and multipath. These effects cause high levels of errors and long durations of service discontinuity that mar the performance of current systems. The prevalence of vision and low-cost inertial sensors provides an attractive opportunity to further increase the positioning and navigation accuracy in such GNSS-challenged environments. This paper presents enhancements to existing multisensor integration systems utilizing the inertial navigation system (INS) to aid in Visual Odometry (VO) outlier feature rejection. A scheme called Aided Visual Odometry (AVO) is developed and integrated with a high performance mechanization architecture utilizing vehicle motion and orientation sensors. The resulting solution exhibits improved state covariance convergence and navigation accuracy, while reducing computational complexity. Experimental verification of the proposed solution is illustrated through three real road trajectories, over two different land vehicles, and using two low-cost inertial measurement units (IMUs).

The characteristics of transforming coordinates from the geocentric system WGS-84 for the Mercator projection under low latitudes conditions

2018 ◽  
Vol 940 (10) ◽  
pp. 2-6
Author(s):  
J.A. Younes ◽  
M.G. Mustafin
Keyword(s):  
Coordinate System ◽  
Satellite System ◽  
Programming Algorithm ◽  
Low Latitude ◽  
Model Calculations ◽  
Mercator Projection ◽  
Low Latitudes ◽  
Rectangular Coordinates ◽  
Global Navigation Satellite ◽  
Coordination Methods

The issue of calculating the plane rectangular coordinates using the data obtained by the satellite observations during the creation of the geodetic networks is discussed in the article. The peculiarity of these works is in conversion of the coordinates into the Mercator projection, while the plane coordinate system on the base of Gauss-Kruger projection is used in Russia. When using the technology of global navigation satellite system, this task is relevant for any point (area) of the Earth due to a fundamentally different approach in determining the coordinates. The fact is that satellite determinations are much more precise than the ground coordination methods (triangulation and others). In addition, the conversion to the zonal coordinate system is associated with errors; the value at present can prove to be completely critical. The expediency of using the Mercator projection in the topographic and geodetic works production at low latitudes is shown numerically on the basis of model calculations. To convert the coordinates from the geocentric system with the Mercator projection, a programming algorithm which is widely used in Russia was chosen. For its application under low-latitude conditions, the modification of known formulas to be used in Saudi Arabia is implemented.

scholarly journals Detecting Apples in the Wild: Potential for Harvest Quantity Estimation

2021 ◽  
Vol 13 (14) ◽  
pp. 8054
Author(s):  
Artur Janowski ◽  
Rafał Kaźmierczak ◽  
Cezary Kowalczyk ◽  
Jakub Szulwic
Keyword(s):  
Image Analysis ◽  
Pilot Study ◽  
Production Management ◽  
Satellite System ◽  
Morphological Operations ◽  
Computational Performance ◽  
Analysis Methods ◽  
Manual Counting ◽  
In The Wild ◽  
Global Navigation Satellite

Knowing the exact number of fruits and trees helps farmers to make better decisions in their orchard production management. The current practice of crop estimation practice often involves manual counting of fruits (before harvesting), which is an extremely time-consuming and costly process. Additionally, this is not practicable for large orchards. Thanks to the changes that have taken place in recent years in the field of image analysis methods and computational performance, it is possible to create solutions for automatic fruit counting based on registered digital images. The pilot study aims to confirm the state of knowledge in the use of three methods (You Only Look Once—YOLO, Viola–Jones—a method based on the synergy of morphological operations of digital imagesand Hough transformation) of image recognition for apple detecting and counting. The study compared the results of three image analysis methods that can be used for counting apple fruits. They were validated, and their results allowed the recommendation of a method based on the YOLO algorithm for the proposed solution. It was based on the use of mass accessible devices (smartphones equipped with a camera with the required accuracy of image acquisition and accurate Global Navigation Satellite System (GNSS) positioning) for orchard owners to count growing apples. In our pilot study, three methods of counting apples were tested to create an automatic system for estimating apple yields in orchards. The test orchard is located at the University of Warmia and Mazury in Olsztyn. The tests were carried out on four trees located in different parts of the orchard. For the tests used, the dataset contained 1102 apple images and 3800 background images without fruits.

GPS-BDS-Galileo double-differenced stochastic model refinement based on least-squares variance component estimation

2021 ◽  
pp. 1-16
Author(s):  
Hong Hu ◽  
Xuefeng Xie ◽  
Jingxiang Gao ◽  
Shuanggen Jin ◽  
Peng Jiang
Keyword(s):  
Stochastic Model ◽  
Least Squares ◽  
Stochastic Models ◽  
Variance Component ◽  
Satellite System ◽  
Variance Component Estimation ◽  
Short Baseline ◽  
Component Estimation ◽  
Zero Baseline ◽  
Global Navigation Satellite

Abstract Stochastic models are essential for precise navigation and positioning of the global navigation satellite system (GNSS). A stochastic model can influence the resolution of ambiguity, which is a key step in GNSS positioning. Most of the existing multi-GNSS stochastic models are based on the GPS empirical model, while differences in the precision of observations among different systems are not considered. In this paper, three refined stochastic models, namely the variance components between systems (RSM1), the variances of different types of observations (RSM2) and the variances of observations for each satellite (RSM3) are proposed based on the least-squares variance component estimation (LS-VCE). Zero-baseline and short-baseline GNSS experimental data were used to verify the proposed three refined stochastic models. The results show that, compared with the traditional elevation-dependent model (EDM), though the proposed models do not significantly improve the ambiguity resolution success rate, the positioning precision of the three proposed models has been improved. RSM3, which is more realistic for the data itself, performs the best, and the precision at elevation mask angles 20°, 30°, 40°, 50° can be improved by 4⋅6%, 7⋅6%, 13⋅2%, 73⋅0% for L1-B1-E1 and 1⋅1%, 4⋅8%, 16⋅3%, 64⋅5% for L2-B2-E5a, respectively.

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