An Optimization Method of Ambiguity Function Based on Multi-Antenna Constrained and Application in Vehicle Attitude Determination

The global navigation satellite system (GNSS)-based multi-antenna attitude determination method has the advantages of a simple algorithm and no error accumulation with time in long endurance operation. However, it is sometimes difficult to simultaneous obtain the fixed solutions of all antennas in vehicle attitude determination. If float or incorrect fixed solutions are used, precision and reliability of attitude cannot be guaranteed. Given this fact, a baseline-constrained ambiguity function method (BCAFM) based on a self-built four GNSS antennas hardware platform is proposed. The coordinates obtained by BCAFM can replace the unreliable real-time kinematic (RTK) float or incorrect fixed solutions, so as to assist the direct method for attitude determination. In the proposed BCAFM, the baseline constraint is applied to improve search efficiency (searching time), and the ambiguity function value (AFV) formula is optimized to enhance the discrimination of true peak. The correctness of the proposed method is verified by vehicle attitude determination results and baseline length difference. Experimental results demonstrate that the function values of error peaks are reduced, and the only true peak can be identified accurately. The valid epoch proportion increases by 14.95% after true peak coordinates are used to replace the GNSS-RTK float or incorrect fixed solutions. The precision of the three attitude angles is 0.54°, 1.46°, and 1.15°, respectively. Meanwhile, the RMS of baseline length difference is 3.8mm.

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Improving DGNSS Performance through the Use of Network RTK Corrections

Remote Sensing ◽

10.3390/rs13091621 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1621

Author(s):

Duojie Weng ◽

Shengyue Ji ◽

Yangwei Lu ◽

Wu Chen ◽

Zhihua Li

Keyword(s):

Carrier Phase ◽

Local Area ◽

Satellite System ◽

High Accuracy ◽

Single Frequency ◽

Baseline Length ◽

Low Latitude ◽

Phase Measurements ◽

Network Rtk ◽

Global Navigation Satellite

The differential global navigation satellite system (DGNSS) is an enhancement system that is widely used to improve the accuracy of single-frequency receivers. However, distance-dependent errors are not considered in conventional DGNSS, and DGNSS accuracy decreases when baseline length increases. In network real-time kinematic (RTK) positioning, distance-dependent errors are accurately modelled to enable ambiguity resolution on the user side, and standard Radio Technical Commission for Maritime Services (RTCM) formats have also been developed to describe the spatial characteristics of distance-dependent errors. However, the network RTK service was mainly developed for carrier-phase measurements on professional user receivers. The purpose of this study was to modify the local-area DGNSS through the use of network RTK corrections. Distance-dependent errors can be reduced, and accuracy for a longer baseline length can be improved. The results in the low-latitude areas showed that the accuracy of the modified DGNSS could be improved by more than 50% for a 17.9 km baseline during solar active years. The method in this paper extends the use of available network RTK corrections with high accuracy to normal local-area DGNSS applications.

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Target Localization Based on Bistatic T/R Pair Selection in GNSS-Based Multistatic Radar System

Remote Sensing ◽

10.3390/rs13040707 ◽

2021 ◽

Vol 13 (4) ◽

pp. 707

Author(s):

Yu’e Shao ◽

Hui Ma ◽

Shenghua Zhou ◽

Xue Wang ◽

Michail Antoniou ◽

...

Keyword(s):

Optimization Methods ◽

Optimization Method ◽

Satellite System ◽

Radar System ◽

Target Localization ◽

Computational Load ◽

Matrix Fusion ◽

Global Navigation Satellite ◽

Multistatic Radar ◽

Combined Algorithm

To cope with the increasingly complex electromagnetic environment, multistatic radar systems, especially the passive multistatic radar, are becoming a trend of future radar development due to their advantages in anti-electronic jam, anti-destruction properties, and no electromagnetic pollution. However, one problem with this multi-source network is that it brings a huge amount of information and leads to considerable computational load. Aiming at the problem, this paper introduces the idea of selecting external illuminators in the multistatic passive radar system. Its essence is to optimize the configuration of multistatic T/R pairs. Based on this, this paper respectively proposes two multi-source optimization algorithms from the perspective of resolution unit and resolution capability, the Covariance Matrix Fusion Method and Convex Hull Optimization Method, and then uses a Global Navigation Satellite System (GNSS) as an external illuminator to verify the algorithms. The experimental results show that the two optimization methods significantly improve the accuracy of multistatic positioning, and obtain a more reasonable use of system resources. To evaluate the algorithm performance under large number of transmitting/receiving stations, further simulation was conducted, in which a combination of the two algorithms were applied and the combined algorithm has shown its effectiveness in minimize the computational load and retain the target localization precision at the same time.

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An Integrated Positioning and Attitude Determination System for Immersed Tunnel Elements: A Simulation Study

Sensors ◽

10.3390/s20247296 ◽

2020 ◽

Vol 20 (24) ◽

pp. 7296

Author(s):

Guanqing Li ◽

Lasse Klingbeil ◽

Florian Zimmermann ◽

Shengxiang Huang ◽

Heiner Kuhlmann

Keyword(s):

Sound Speed ◽

Attitude Determination ◽

Satellite System ◽

Sufficient Accuracy ◽

Navigation Satellite ◽

Accuracy Analysis ◽

Absolute Position ◽

Immersed Tunnel ◽

Determination System ◽

Global Navigation Satellite

Immersed tunnel elements need to be exactly controlled during their immersion process. Position and attitude of the element should be determined quickly and accurately to navigate the element from the holding area to the final location in the tunnel trench. In this paper, a newly-developed positioning and attitude determination system, integrating a 3-antenna Global Navigation Satellite System (GNSS) system, an inclinometer and a range-measurement system, is presented. The system is designed to provide the absolute position of both ends of the element with sufficient accuracy in real time. Special attention in the accuracy analysis is paid to the influence of GNSS multipath error and sound speed profile. Simulations are conducted to illustrate the performance of the system in different scenarios. If both elements are very close, the accuracies of the system are higher than 0.02 m in the directions perpendicular to and along the tunnel axis.

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A Novel GNSS Attitude Determination Method Based on Primary Baseline Switching for A Multi-Antenna Platform

Remote Sensing ◽

10.3390/rs12050747 ◽

2020 ◽

Vol 12 (5) ◽

pp. 747

Author(s):

Peng Zhang ◽

Yinzhi Zhao ◽

Huan Lin ◽

Jingui Zou ◽

Xinzhe Wang ◽

...

Keyword(s):

Attitude Determination ◽

Low Cost ◽

Satellite System ◽

Poor Quality ◽

Integrated Navigation ◽

Determination Method ◽

Integrated Navigation System ◽

Determination System ◽

Vehicle Test ◽

Global Navigation Satellite

The global navigation satellite system (GNSS)-based attitude determination system has attracted more and more attention with the advantages of having simplified algorithms, a low price and errors that do not accumulate over time. However, GNSS signals may have poor quality or lose lock in some epochs with the influence of signal fading and the multipath effect. When the direct attitude determination method is applied, the primary baseline may not be available (ambiguity is not fixed), leading to the inability of attitude determination. With the gradual popularization of low-cost receivers, making full use of spatial redundancy information of multiple antennas brings new ideas to the GNSS-based attitude determination method. In this paper, an attitude angle conversion algorithm, selecting an arbitrary baseline as the primary baseline, is derived. A multi-antenna attitude determination method based on primary baseline switching is proposed, which is performed on a self-designed embedded software and hardware platform. The proposed method can increase the valid epoch proportion and attitude information. In the land vehicle test, reference results output from a high-accuracy integrated navigation system were used to evaluate the accuracy and reliability. The results indicate that the proposed method is correct and feasible. The valid epoch proportion is increased by 16.2%, which can effectively improve the availability of attitude determination. The RMS of the heading, pitch and roll angles are 0.52°, 1.25° and 1.16°.

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Effect of Nonlinear Baseline Length Constraint on Global Navigation Satellite System Compass: A Theoretical Analysis

Mathematical Problems in Engineering ◽

10.1155/2020/6037841 ◽

2020 ◽

Vol 2020 ◽

pp. 1-6

Author(s):

Yanlong Chen ◽

Jincheng Fan ◽

Guobin Chang ◽

Siyu Zhang

Keyword(s):

Global Navigation Satellite System ◽

Low Cost ◽

Satellite System ◽

Baseline Length ◽

Navigation Satellite ◽

Angle Estimation ◽

Length Constraint ◽

Simple Scaling ◽

Global Navigation ◽

Global Navigation Satellite

GNSS (global navigation satellite system) compass is a low-cost, high-precision, and temporally stable north-finding technique. While the nonlinear baseline length constraint is widely known to be important in ambiguity resolution of GNSS compass, its direct effect on yaw angle estimation is theoretically analyzed in this work. Four different methods are considered with different ways in which the length constraint is made use of as follows: one without considering the constraints, one with simple scaling, one with indirect statistical scaling, and one with direct statistical scaling. It is found that simple scaling does not have any effect on yaw estimation; indirect and direct statistical scalings are equivalent to each other with both being able to increase the precision. The analysis and the conclusion developed in this work can go in parallel for the case of the tilt angle estimation.

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Performance Trades for Multiantenna GNSS Multisensor Attitude Determination Systems

International Journal of Aerospace Engineering ◽

10.1155/2018/4871239 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12

Author(s):

Nathan A. Tehrani ◽

Jason N. Gross

Keyword(s):

Attitude Determination ◽

Inertial Sensors ◽

Satellite System ◽

Attitude Estimation ◽

Multiple Antenna ◽

Estimation Performance ◽

Trade Offs ◽

Sensing Platforms ◽

Global Navigation Satellite ◽

System Configurations

We present various performance trades for multiantenna global navigation satellite system (GNSS) multisensor attitude estimation systems. In particular, attitude estimation performance sensitivity to various error sources and system configurations is assessed. This study is motivated by the need for system designers, scientists, and engineers of airborne astronomical and remote sensing platforms to better determine which system configuration is most suitable for their specific application. In order to assess performance trade-offs, the attitude estimation performance of various approaches is tested using a simulation that is based on a stratospheric balloon platform. For GNSS errors, attention is focused on multipath, receiver measurement noise, and carrier-phase breaks. For the remaining attitude sensors, different performance grades of sensors are assessed. Through a Monte Carlo simulation, it is shown that, under typical conditions, sub-0.1-degree attitude accuracy is available when using multiple antenna GNSS data only, but that this accuracy can degrade to degree level in some environments warranting the inclusion of additional attitude sensors to maintain the desired level of accuracy. Further, we show that integrating inertial sensors is more valuable whenever accurate pitch and roll estimates are critical.

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Integrated GNSS Attitude and Position Determination based on an Affine Constrained Model

Journal of Navigation ◽

10.1017/s0373463317000522 ◽

2017 ◽

Vol 71 (1) ◽

pp. 134-150

Author(s):

Haiying Liu ◽

Lei Xu ◽

Xiaolin Meng ◽

Xibei Chen ◽

Junyi Li

Keyword(s):

Attitude Determination ◽

Satellite System ◽

Determination Method ◽

Position Determination ◽

Static Data ◽

Constraint Information ◽

Constrained Model ◽

Global Navigation Satellite ◽

Constraint Model ◽

Gnss Data

Global Navigation Satellite System (GNSS) attitude determination and positioning play an important role in many navigation applications. However, the two GNSS-based problems are usually treated separately. This ignores the constraint information of the GNSS antenna array and the accuracy is limited. To improve the performance of navigation, an integrated attitude and position determination method based on an affine constraint model is presented. In the first part, the GNSS array model and affine constrained attitude determination method are compared with the unconstrained methods. Then the integrated attitude and position determination method is presented. The performance of the proposed method is tested with a series of static data and dynamic experimental GNSS data. The results show that the proposed method can improve the success rate of ambiguity resolution to further improve the accuracy of attitude determination and relative positioning compared to the unconstrained methods.

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Accounting for Inter-System Bias in DGNSS Positioning with GPS/GLONASS/BDS/Galileo

Journal of Navigation ◽

10.1017/s0373463316000825 ◽

2017 ◽

Vol 70 (4) ◽

pp. 686-698 ◽

Cited By ~ 17

Author(s):

Hui Liu ◽

Bao Shu ◽

Longwei Xu ◽

Chuang Qian ◽

Rufei Zhang ◽

...

Keyword(s):

Global Positioning System ◽

Simple Algorithm ◽

Satellite System ◽

Harsh Environments ◽

Positioning System ◽

Gnss Positioning ◽

Global Positioning ◽

System Bias ◽

Global Navigation Satellite ◽

Reliability And Availability

Code Differential Global Positioning System (DGPS) is widely used in satellite navigation and positioning because of its simple algorithm and preferable precision. Multi-Global Navigation Satellite System (GNSS) is expected to enhance the accuracy, reliability and availability of Differential GNSS (DGNSS) positioning. Traditional DGNSS models should set separate clock parameters due to the clock differences between the different systems. Awareness of the Inter-System Bias (ISB) could help to maximise the redundancy of the positioning model, thus improving the performance of multi-GNSS positioning. This paper aims to examine the inter-system bias of GPS/GLONASS/BeiDou (BDS)/Galileo and their benefits in DGNSS positioning. Results show that Differential ISB (DISB) characteristics vary with different receiver types and systems. The size of DISB could reach metre-level and the precision of estimated DISBs can reach approximately several centimetres within tens of epochs. Therefore, a new real-time DGNSS model that accounts for ISB is proposed. After differential ISBs are initialised, positioning with four satellites from arbitrarily the same or different systems can be realised. Moreover, compared with the traditional DGNSS model, the precision of the positioning results with the new model are obviously improved, especially in harsh environments.

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