scholarly journals Selected Issues and Constraints of Image Matching in Terrain-Aided Navigation: A Comparative Study

2020 ◽  
Author(s):  
Piotr Turek ◽  
Stanisław Grzywiński ◽  
Witold Bużantowicz
Keyword(s):  
Navigation System ◽  
Operating Conditions ◽  
Global Navigation Satellite Systems ◽  
Reference Image ◽  
Satellite Systems ◽  
Performance Effectiveness ◽  
Reference Images ◽  
Global Navigation Satellite ◽  
Navigational Systems ◽  
Uav Navigation

The sensitivity of global navigation satellite systems to disruptions precludes their use in conditions of armed conflict with an opponent possessing comparable technical capabilities. In military unmanned aerial vehicles (UAVs) the aim is to obtain navigational data to determine the location and correction of flight routes by means of other types of navigational systems. To correct the position of an UAV relative to a given trajectory, the systems that associate reference terrain maps with image information can be used. Over the last dozen or so years, new, effective algorithms for matching digital images have been developed. The results of their performance effectiveness are based on images that are fragments taken from source files, and therefore their qualitatively identical counterparts exist in the reference images. However, the differences between the reference image stored in the memory of navigation system and the image recorded by the sensor can be significant. In this paper modern methods of image registration and matching to UAV position refinement are compared, and adaptation of available methods to the operating conditions of the UAV navigation system is discussed.

Geolocal – A New System for Geo-Referencing: Analysis of Base Distribution

2020 ◽  
pp. 1-13
Author(s):  
Eduardo P. Macho ◽  
Sergio V.D. Pamboukian ◽  
Emília Correia
Keyword(s):  
Time Delay ◽  
Navigation System ◽  
Measurement Errors ◽  
Global Navigation Satellite Systems ◽  
Navigation Satellite ◽  
Dilution Of Precision ◽  
Satellite Systems ◽  
Global Navigation ◽  
Global Navigation Satellite ◽  
New System

Geolocal is a new navigation system conceived and patented in Brazil, whose purpose is to be independent of other global navigation satellite systems (GNSS). It has an ‘inverted-GNSS’ configuration with at least four bases on the ground at known geodesic position coordinates and a repeater in space. Simulations were performed to determine the precision of Geolocal using different quantities and distributions of bases. They showed that this precision is enhanced when the quantity of bases increases, as long as the elevation angles of the new bases included are higher than the average and when the bases are evenly distributed around the repeater, but mainly when the time delay at the repeater is known in advance and when the measurement errors that generate uncertainties are reduced. The position dilution of precision (PDOP) was also calculated, confirming that precision is enhanced by the quantity of bases and by their distribution.

scholarly journals Seamless Indoor-Outdoor Navigation based on GNSS, INS and Terrestrial Ranging Techniques

2017 ◽  
Vol 70 (6) ◽  
pp. 1183-1204 ◽  
Author(s):  
Wei Jiang ◽  
Yong Li ◽  
Chris Rizos ◽  
Baigen Cai ◽  
Wei Shangguan
Keyword(s):  
Navigation System ◽  
Global Navigation Satellite Systems ◽  
Indoor Environments ◽  
Integrated Navigation ◽  
Satellite Systems ◽  
Integrated Navigation System ◽  
Outdoor Environments ◽  
Federated Kalman Filter ◽  
Indoor And Outdoor Environments ◽  
Global Navigation Satellite

We describe an integrated navigation system based on Global Navigation Satellite Systems (GNSS), an Inertial Navigation System (INS) and terrestrial ranging technologies that can support accurate and seamless indoor-outdoor positioning. To overcome severe multipath disturbance in indoor environments, Locata technology is used in this navigation system. Such a “Locata-augmented” navigation system can operate in different positioning modes in both indoor and outdoor environments. In environments where GNSS is unavailable, e.g. indoors, the proposed system is designed to operate in the Locata/INS “loosely-integrated” mode. On the other hand, in outdoor environments, all GNSS, Locata and INS measurements are available, and all useful information can be fused via a decentralised Federated Kalman filter. To evaluate the proposed system for seamless indoor-outdoor positioning, an indoor-outdoor test was conducted at a metal-clad warehouse. The test results confirmed that the proposed navigation system can provide continuous and reliable position and attitude solutions, with the positioning accuracy being better than five centimetres.

scholarly journals UAVS ENHANCED NAVIGATION IN OUTDOOR GNSS DENIED ENVIRONMENT USING UWB AND MONOCULAR CAMERA SYSTEMS

2019 ◽  
Vol XLII-2/W13 ◽  
pp. 665-672 ◽  
Author(s):  
S. Zahran ◽  
A. Masiero ◽  
M. M. Mostafa ◽  
A. M. Moussa ◽  
A. Vettore ◽  
...  
Keyword(s):  
Navigation System ◽  
Low Cost ◽  
Global Navigation Satellite Systems ◽  
Ultra Wideband ◽  
Measurement Unit ◽  
Satellite Systems ◽  
Monocular Camera ◽  
Camera Systems ◽  
Global Navigation Satellite ◽  
The Cost

<p><strong>Abstract.</strong> The demand for small Unmanned Aerial Vehicles (UAVs) is massively increasing these days, due to the wide variety of applications utilizing such vehicles to perform tasks that may be dangerous or just to save time, effort, or cost. Small UAVs navigation system mainly depends on the integration between Global Navigation Satellite Systems (GNSS) and Inertial Measurement Unit (INS) to estimate the Positions, Velocities, and Attitudes (PVT) of the vehicle. Without GNSS such UAVs cannot navigate for long periods of time depending on INS alone, as the low-cost INS typically exhibits massive accumulation of errors during GNSS absence. Given the importance of ensuring full operability of the UAVs even during GNSS signals unavailability, other sensors must be used to bound the INS errors and enhance the navigation system performance. This paper proposes an enhanced UAV navigation system based on integration between monocular camera, Ultra-Wideband (UWB) system, and INS. In addition to using variable EKF weighting scheme. The paper also investigates this integration in the case of low density of UWB anchors, to reduce the cost required for such UWB system infrastructure. A GoPro Camera and UWB rover were attached to the belly of a quadcopter, an on the shelf commercial drone (3DR Solo), during the experimental flight. The velocity of the vehicle is estimated with Optical Flow (OF) from camera successive images, while the range measurements between the UWB rover and the stationary UWB anchors, which were distributed on the field, were used to estimate UAV position.</p>

scholarly journals Development and Implementation of the Robot Prototype with Inertial Navigation for Work in the Arctic

2019 ◽  
Vol 8 (4) ◽  
pp. 4584-4590
Keyword(s):  
Navigation System ◽  
Rapid Development ◽  
Access Point ◽  
Global Navigation Satellite Systems ◽  
Wireless Access ◽  
The Arctic ◽  
Satellite Systems ◽  
Determination Error ◽  
Micromechanical Sensors ◽  
Global Navigation Satellite

Currently, there is a very rapid development of robotics. People use robots in many areas of their activities. Especially valuable is the use of robots in hazardous conditions for humans, in particular in studies in the Arctic. In this case, there is an acute problem of navigation. The use of global navigation satellite systems (GNSS) in the Arctic is difficult due to the small number of satellites and the influence of Aurora. Therefore, we chose the inertial type of navigation for the prototype of the robot. We used LSM330DL micromechanical sensors and Atmega8-16AU microcontroller to create a navigation system. We used wireless access point Ubiquiti Bullet M2HP Titanium to connect the robot with researchers. Tests of a prototype of a robot on a wheeled platform showed that the coordinate determination error does not exceed 6%. Tests of the navigation system were carried out up to -20°C. System components allow operation up to -40°C. The proposed navigation system can be used to create robots for work in the Arctic.

Investigation of Alternative Parameters for Immunity-based UAV Navigation in GNSS-denied Environment

2020 ◽  
Vol 09 (01) ◽  
pp. 65-72
Author(s):  
Mohanad Alnuaimi ◽  
Mario G. Perhinschi
Keyword(s):  
Autonomous Navigation ◽  
Dead Reckoning ◽  
Global Navigation Satellite Systems ◽  
External Information ◽  
Artificial Immune ◽  
Tracking Errors ◽  
Satellite Systems ◽  
Vehicle Position ◽  
Global Navigation Satellite ◽  
Uav Navigation

This paper is focused on analyzing effects of several significant parameters on the performance of an immunity-inspired methodology for autonomous navigation of unmanned air vehicles when measurements from global navigation satellite systems (GNSS) or similar current sources, including external information of opportunity, are not available. An artificial immune system (AIS) provides corrections to a dead reckoning algorithm for adequate estimates of vehicle position and velocity. Parameter effects are assessed and analyzed through simulation in terms of trajectory tracking errors during autonomous flight.

scholarly journals ENHANCED UAV NAVIGATION USING HALL-MAGNETIC AND AIR-MASS FLOW SENSORS IN INDOOR ENVIRONMENT

2019 ◽  
Vol IV-2/W5 ◽  
pp. 187-194 ◽  
Author(s):  
S. Zahran ◽  
A. Moussa ◽  
N. El-Sheimy
Keyword(s):  
Mass Flow ◽  
Navigation System ◽  
System Performance ◽  
Low Cost ◽  
Dead Reckoning ◽  
Global Navigation Satellite Systems ◽  
Flow Sensors ◽  
Air Mass ◽  
Satellite Systems ◽  
Global Navigation Satellite

<p><strong>Abstract.</strong> The use of Unmanned Aerial Vehicles (UAVs) in many commercial and emergency applications has the potential to dramatically alter several industries, and, in the process, change our attitudes regarding their impact on our daily lives activities. The navigation system of these UAVs mainly depends on the integration between the Global Navigation Satellite Systems (GNSS) and Inertial Navigation System (INS) to estimate the positions, velocities, and attitudes (PVT) of the UAVs. However, GNSS signals are not always available everywhere and therefore during GNSS signal outages, the navigation system performance will deteriorate rapidly especially when using low-cost INS. Additional aiding sensors are required, during GNSS signal outages, to bound the INS errors and enhance the navigation system performance. This paper proposes the utilization of two sensors (Hall-magnetic and Air-Mass flow sensors) to act as flying odometer by estimating the UAV forward velocity. The estimated velocity is then integrated with INS through Extended Kalman Filter (EKF) to enhance the navigation solution estimation. A real experiment was carried out with the 3DR quadcopter while the proposed system is attached on the top of the quadcopter. The results showed great enhancement in the navigation system performance with more than 98% improvement when compared to the free running INS solution (dead-reckoning).</p>

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