scholarly journals Electronic Navigation System based on the use of Alternate Coordinate System and Polar Stereographic Projection for UAVs operating in Polar Regions

2019 ◽  
Vol 1 (2) ◽  
pp. 46-53
Author(s):  
Ali Kissai ◽  
Milton Smith
Keyword(s):  
Coordinate System ◽  
Navigation System ◽  
Stereographic Projection ◽  
Polar Regions

scholarly journals A new polar alignment algorithm based on the Huber estimation filter with the aid of BeiDou Navigation Satellite System

2021 ◽  
Vol 17 (3) ◽  
pp. 155014772110041
Author(s):  
Bin Zhao ◽  
Qinghua Zeng ◽  
Jianye Liu ◽  
Chunlei Gao ◽  
Tianyu Zhao
Keyword(s):  
Kalman Filter ◽  
Navigation System ◽  
Inertial Navigation System ◽  
Satellite System ◽  
Estimation Accuracy ◽  
Polar Regions ◽  
Alignment Algorithm ◽  
Navigation Satellite ◽  
Beidou Navigation Satellite System ◽  
Non Gaussian

For aircrafts equipped with BeiDou Navigation Satellite System/Strapdown Inertial Navigation System integrated navigation system, BeiDou Navigation Satellite System information can be used to achieve autonomous alignment. However, due to the complex polar environment and multipath effect, BeiDou Navigation Satellite System measurement noise often exhibits a non-Gaussian distribution that will severely degrade the estimation accuracy of standard Kalman filter. To address this problem, a new polar alignment algorithm based on the Huber estimation filter is proposed in this article. Considering the special geographical conditions in the polar regions, the dynamic model and the measurement model of BeiDou Navigation Satellite System/Strapdown Inertial Navigation System integrated alignment system in the grid frame are derived in this article. The BeiDou Navigation Satellite System measurement noise characteristics in the polar regions are analyzed and heavy-tailed characteristics are simulated, respectively. Since the estimation accuracy of standard Kalman filter can be severely degraded under non-Gaussian noise, a Kalman filter based on the Huber estimation is designed combining grid navigation system and generalized maximum likelihood estimation. The simulation and experiment results demonstrate that the proposed algorithm has better robustness under non-Gaussian noise, and it is effective in the polar regions. By employing the proposed algorithm, the rapidity and accuracy of the alignment process can be improved.

Image Motion Compensation Control Technology of Unmanned Aerial Vehicle (UAV) Airborne Photoelectric Reconnaissance Platform

2020 ◽  
Vol 15 (6) ◽  
pp. 753-761
Author(s):  
Yuchao Fang
Keyword(s):  
Coordinate System ◽  
Motion Compensation ◽  
Navigation System ◽  
Inertial Navigation System ◽  
Geometric Model ◽  
Inertial Navigation ◽  
Image Motion ◽  
Attitude Angle ◽  
Internal Parameters ◽  
Image Compensation

Airborne photoelectric platform has a wide application prospect in the field of imaging, especially in the field of UAV reconnaissance. However, in the process of image acquisition, the photoelectric platform equipment will produce obvious image shift because of its own attitude change or speed instability, so it is necessary to compensate the collected image. In this study, when the image motion compensation is carried out, the internal and external parameters of the camera are adjusted, and the geometric model of the image is established. The Camera Calibration Toolbox provided by MatLab is used to calibrate the internal parameters of camera. At the same time, when obtaining the camera's internal parameters, the corresponding flight attitude angle is obtained with the aid of the inertial navigation system. At the same time of acquiring the attitude of the aircraft by hardware, it is necessary to obtain the image shift coefficient by using the function. The coordinate system needs to be transformed into a coordinate system suitable for the inertial navigation system, so as to facilitate the calculation of external parameters of the camera. The transformation matrix from image moving image to normal image can be established by obtaining the parameters inside and outside the camera. Through bilinear interpolation, the matrix is derived in MatLab environment. In the experiment, 16 black-and-white grid images are selected to obtain the attitude angle, so as to complete the calculation process of the conversion matrix. Then, the images with image shift are screened out from the images taken in aerial state. The method proposed in this study is used for image compensation. According to the root mean square error analysis, the image compensation scheme proposed in this study is helpful to the imaging application of UAV airborne platform.

scholarly journals Based on Grid Reference Frame for SINS/CNS Integrated Navigation System in the Polar Regions

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Song Lijun ◽  
Zhao Wanliang ◽  
Cheng Yuxiang ◽  
Chen Xiaozhen
Keyword(s):  
Reference Frame ◽  
Navigation System ◽  
Inertial Navigation System ◽  
Inertial Navigation ◽  
Polar Regions ◽  
Integrated Navigation ◽  
Integrated Navigation System ◽  
Celestial Navigation ◽  
Low Latitudes ◽  
And Performance

As the inertial navigation system cannot meet the precision requirements of global navigation in the special geographical environment of the Polar Regions, this paper presents Strapdown Inertial Navigation System (SINS)/Celestial Navigation System (CNS) integrated navigation system of airborne based on Grid Reference Frame (GRF) and the simulation is carried out. The result of simulation shows that the SINS/CNS integrated navigation system is superior to the single subsystem in precision and performance, which not only effectively inhibits the error caused by gyro drift but also corrects the navigation parameters of system without delay. Comparing the simulation in the middle and low latitudes and in the Polar Regions, the precision of SINS/CNS integrated navigation system is the same in the middle and low latitudes and in the Polar Regions.

The Presentation of Information in Combat Aircraft

1977 ◽  
Vol 30 (3) ◽  
pp. 415-421
Author(s):  
L. T. J. Salmon
Keyword(s):  
Coordinate System ◽  
Navigation System ◽  
Sufficient Accuracy ◽  
Compromise Solution ◽  
Actual System ◽  
Combat Aircraft

The prime purpose of the navigation system in a combat aircraft is to determine the relative positions of aircraft and target with sufficient accuracy to enable a weapon to be released. In practice the actual system installed in the aircraft is a compromise solution, which depends on three factors, namely, the mission to be flown, the type of aircraft and the navigation phases through which the aircraft flies while performing the mission. Broadly speaking there are two types of navigation phase; these will be termed macronavigation and micronavigation. Macronavigation is concerned with the navigation of an aircraft to some pre-determined point on the Earth's surface while micronavigation is the final, highly accurate navigation phase required for weapon release. Micronavigation can be further sub-divided into static and dynamic micronavigation; static when the target and the coordinate system within which it exists are fixed, and dynamic when the target moves within a coordinate system which is defined by the attacking aircraft.

Some Considerations of Free-gyro Failure in Air Navigation

1960 ◽  
Vol 13 (1) ◽  
pp. 78-88
Author(s):  
J. F. Green
Keyword(s):  
Navigation System ◽  
Polar Regions ◽  
Directional Information ◽  
Signal Selection ◽  
Gyro System ◽  
Automatic Navigation ◽  
The Future ◽  
Single Instrument

In polar regions great reliance has to be placed on the directional information provided by a free azimuth gyro. For sufficient reliability the use of three such gyros is advocated. An analysis is made of ‘the best two out of three’ principle—taking into account the fact that in practice no two gyro readings will be identical.It is demonstrated that for a given reliability attaching to an individual gyro, the reliability of a three-gyro system represents a vast improvement over a single instrument and that there is an optimum way of using the information presented. The advantages of middle signal selection are pointed out and the dangers associated with mean signal selection are explained. Attention is drawn to the extension of this principle to the problems of triple-signal selection in the automatic navigation system of the future.

scholarly journals Transverse Navigation under the Ellipsoidal Earth Model and its Performance in both Polar and Non-polar areas

2015 ◽  
Vol 69 (2) ◽  
pp. 335-352 ◽  
Author(s):  
Yi-qing Yao ◽  
Xiao-su Xu ◽  
Yao Li ◽  
Yi-ting Liu ◽  
Jin Sun ◽  
...  
Keyword(s):  
Navigation System ◽  
Inertial Measurement Unit ◽  
Inertial Navigation System ◽  
Polar Region ◽  
Field Tests ◽  
Measurement Unit ◽  
Earth Model ◽  
Polar Regions ◽  
Reference Information ◽  
Spherical Earth

The transverse navigation system has been designed and developed to solve the challenges of navigation in polar regions. However, considerable theoretical errors are introduced into the system when the spherical Earth model is adopted. To tackle this problem, a transverse navigation mechanism under the ellipsoidal Earth model has been proposed in this research and the application regions of the proposed algorithm are specified and evaluated through error analysis. The analysis shows the presented transverse navigation system works in both polar and part of the non-polar regions. Field tests were conducted to evaluate the navigation performance in Nanjing, a non-polar region. A novel experimental method, where the field test data in mid-latitude areas was used to simulate the real Inertial Measurement Unit (IMU) data and the reference information in polar regions, was adopted to investigate the performance of the proposed algorithm in polar areas. The results show: that in the mid-latitude areas, the presented transverse navigation system achieves the same accuracy as the traditional inertial navigation system and that in polar regions, the proposed transverse mechanism outperforms the traditional method with a much lower error in longitude and yaw.

scholarly journals A Fault-Tolerant Polar Grid SINS/DVL/USBL Integrated Navigation Algorithm Based on the Centralized Filter and Relative Position Measurement

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3899 ◽  
Author(s):  
Lin Zhao ◽  
Yingyao Kang ◽  
Jianhua Cheng ◽  
Mouyan Wu
Keyword(s):  
Relative Position ◽  
Navigation System ◽  
Detection Method ◽  
Fault Tolerant ◽  
Polar Regions ◽  
Integrated Navigation ◽  
Position Measurement ◽  
Integrated Navigation System ◽  
Position Errors ◽  
Navigation Algorithm

Navigation is a precondition for ocean space vehicles to work safely in polar regions. The traditional polar algorithms employ the grid strapdown inertial navigation system (SINS) as the backbone and Doppler velocity log (DVL) output velocity as measurements to constitute the integrated navigation system, of which, however, the position errors still accumulate with time. The ultra-short baseline (USBL) position system can provide position information that can be used to improve the performance of the SINS/DVL integrated system. Therefore, a grid SINS/DVL/USBL integrated algorithm for polar navigation is proposed in this paper. In order to extend the availability of the USBL and improve integration accuracy in polar regions, the USBL observation model is established based on the relative position measurement firstly. Then, a grid SINS/DVL/USBL integrated algorithm is proposed to fuse the information of these sensors with a modified Kalman filter (MKF) dealing with the sparse USBL output. Finally, a vector fault detection method, which takes the measurements as detection objects instead of the filter, is designed to locate the measurement fault and can be employed by the centralized filter to improve the fault-tolerant. Simulation and experiment results show that the proposed grid SINS/DVL/USBL integrated navigation system can further restrain SINS errors especially the position errors effectively. Meanwhile, the vector fault detection method can detect and isolate the fault measurements of centralized filter immediately and accurately. Therefore, the proposed fault-tolerant grid SINS/DVL/USBL integrated navigation algorithm can improve the reliability and accuracy of polar navigation for ocean space application.

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