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 A New Era in Spatial Data Recording: Low-Cost GNSS

2019 ◽  
Vol 7 (2) ◽  
pp. 169-177 ◽  
Author(s):  
Austin Chad Hill ◽  
Fred Limp ◽  
Jesse Casana ◽  
Elise Jakoby Laugier ◽  
Malcolm Williamson
Keyword(s):  
Spatial Data ◽  
Low Cost ◽  
Three Dimensional ◽  
Global Navigation Satellite Systems ◽  
New Era ◽  
Satellite Systems ◽  
Small Areas ◽  
Rtk Gps ◽  
Global Navigation Satellite ◽  
The Cost

AbstractArchaeologists have long recognized that precise three-dimensional coordinates are critical for recording objects and features across sites and landscapes. Traditionally, for relatively small areas, an optical transit or, more recently, an electronic distance measurement device (EDM) has been used to acquire these three-dimensional points. While effective, such systems have significant limitations in that they require a clear line of site. Real-time kinematic (RTK) GPS/GNSS systems (Global Positioning System/Global Navigation Satellite Systems) have been available for well over a decade, and can provide quick and accurate point measurements over a wide area without many of the limitation of older technologies. The cost of such systems, however, has generally been prohibitive for archaeologists, and so their use has been rare. Recently, a new generation of low-cost systems has become available, making this technology more accessible to a wider user base. This article describes the use, accuracy, and limitations of one such low-cost system, the Emlid Reach RS, to show why this is an important tool for archaeological fieldwork.

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>

scholarly journals A Surface KInematics Buoy (SKIB) for wave-current interactions studies

2018 ◽  
Author(s):  
Pedro Veras Guimarães ◽  
Fabrice Ardhuin ◽  
Peter Sutherland ◽  
Mickael Accensi ◽  
Michel Hamon ◽  
...  
Keyword(s):  
Low Cost ◽  
Short Wave ◽  
Global Navigation Satellite Systems ◽  
Motion Sensor ◽  
Satellite Systems ◽  
Ocean Surface Waves ◽  
Sensing Applications ◽  
Hull Design ◽  
Sensor Package ◽  
Global Navigation Satellite

Abstract. Global Navigation Satellite Systems (GNSS) and modern motion-sensor packages allow the measurement of ocean surface waves with low-cost drifters. Drifting along or across current gradients provides unique measurements of wave-current interactions. In this study, we investigate the response of several combinations of GNSS receiver, motion-sensor package and hull design in order to define a prototype surface kinematic buoy (SKIB) that is particularly optimized for measuring wave-current interactions, including relatively short wave components (relative frequency around 1 Hz) that are important for air-sea interactions and remote sensing applications. The comparison with existing Datawell Directional Waverider and SWIFT buoys, as well as stereo-video imagery demonstrates the accuracy of SKIB. The use of low-cost accelerometers and a spherical ribbed and skirted hull design provide acceptable heave spectra, while velocity estimates from GNSS receivers yield a mean direction and directional spread. Using a low-power acquisition board allows autonomous deployments over several months with data transmitted by satellite. The capability to measure current-induced wave variations is illustrated with data acquired in a macro-tidal coastal environment.

scholarly journals Centimeter-Level Recording for All: Field Experimentation with New, Affordable Geolocation Technology

2019 ◽  
Vol 7 (4) ◽  
pp. 353-365 ◽  
Author(s):  
Peter J. Cobb ◽  
Tiffany Earley-Spadoni ◽  
Philip Dames
Keyword(s):  
Spatial Data ◽  
Field Data ◽  
Low Cost ◽  
Field Application ◽  
Global Navigation Satellite Systems ◽  
Precise Location ◽  
Satellite Systems ◽  
Surface Survey ◽  
Field Experimentation ◽  
Global Navigation Satellite

AbstractThe methodical recording and representation of spatial data are central to archaeological fieldwork and research. Until recently, centimeter-level precise geolocation equipment was the exclusive domain of researchers who could afford setups costing tens of thousands of dollars. However, high-quality measurements are being made more accessible by rapidly evolving technologies. These new tools, when used together with mobile technology for efficiently recording field data, open up the possibility of capturing the precise location of every find during an archaeological surface survey. An important step in reaching the desired outcome—centimeter-level recording for all—is experimentation with a variety of emerging low-cost setups. Accordingly, we tested the Reach and Reach RS, differential global navigation satellite systems (dGNSS) equipment produced by the company Emlid, during a surface survey in Armenia in June 2018. Our field application demonstrates that the use of dGNSS is already possible and that the described advances in precision enable improved recording and representation of spatial data.

scholarly journals Low cost GNSS receivers in time synchronization systems

2018 ◽  
Vol 67 (1) ◽  
pp. 65-72
Author(s):  
Grzegorz Czopik ◽  
Tomasz Kraszewski
Keyword(s):  
Time Synchronization ◽  
Low Cost ◽  
Global Navigation Satellite Systems ◽  
Satellite Systems ◽  
Time Frequency ◽  
Delay Times ◽  
Gnss Receivers ◽  
Frequency Counter ◽  
The One ◽  
Global Navigation Satellite

The GNSS (GNSS — Global Navigation Satellite Systems) receivers can be utilized to obtain accurate time markers. The preliminary results of the cheap GNSS receivers’ tests are presented in the paper. The one receiver’s price (including antenna) does not exceed 30 $. The studies on the use of receivers in the time synchronization systems were executed. Three identical models of receiver modules were used. The 1PPS (1PPS — 1 Pulse Per Second) signals available on the receiver’s output were used. The 1PPS’s main time characteristics were described. Delay times between different receivers 1PPS signals were measured. Measurements were taken using 1 GHz oscilloscope and precise time/frequency counter T3200U. Keywords: time synchronization, 1PPS, GNSS, GPS time

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 Enhanced Drone Navigation in GNSS Denied Environment Using VDM and Hall Effect Sensor

2019 ◽  
Vol 8 (4) ◽  
pp. 169 ◽  
Author(s):  
Shady Zahran ◽  
Adel Moussa ◽  
Naser El-Sheimy
Keyword(s):  
Hall Effect ◽  
Low Cost ◽  
Integrated System ◽  
Global Navigation Satellite Systems ◽  
Satellite Systems ◽  
Hall Effect Sensor ◽  
Aerial Vehicle ◽  
Heading Estimation ◽  
Global Navigation Satellite ◽  
Vehicle Dynamic Model

The last decade has witnessed a wide spread of small drones in many civil and military applications. With the massive advancement in the manufacture of small and lightweight Inertial Navigation System (INS), navigation in challenging environments became feasible. Navigation of these small drones mainly depends on the integration of Global Navigation Satellite Systems (GNSS) and INS. However, the navigation performance of these small drones deteriorates quickly when the GNSS signals are lost, due to accumulated errors of the low-cost INS that is typically used in these drones. During GNSS signal outages, another aiding sensor is required to bound the drift exhibited by the INS. Before adding any additional sensor on-board the drones, there are some limitations that must be taken into considerations. These limitations include limited availability of power, space, weight, and size. This paper presents a novel unconventional method, to enhance the navigation of autonomous drones in GNSS denied environment, through a new utilization of hall effect sensor to act as flying odometer “Air-Odo” and vehicle dynamic model (VDM) for heading estimation. The proposed approach enhances the navigational solution by estimating the unmanned aerial vehicle (UAV) velocity, and heading and fusing these measurements in the Extended Kalman Filter (EKF) of the integrated system.

Multi-Sensor Integrated Navigation in Urban and Indoor Environments

2018 ◽  
pp. 397-442 ◽  
Author(s):  
Mohamed Atia
Keyword(s):  
Sensor Fusion ◽  
Global Navigation Satellite Systems ◽  
Measurement Unit ◽  
Indoor Environments ◽  
Integrated Navigation ◽  
Satellite Systems ◽  
Tightly Coupled ◽  
Sensor Processing ◽  
Global Navigation Satellite ◽  
Dense Urban Environment

The art of multi-sensor processing, or “sensor-fusion,” is the ability to optimally infer state information from multiple noisy streams of data. One major application area where sensor fusion is commonly used is navigation technology. While global navigation satellite systems (GNSS) can provide centimeter-level location accuracy worldwide, they suffer from signal availability problems in dense urban environment and they hardly work indoors. While several alternative backups have been proposed, so far, no single sensor or technology can provide the desirable precise localization in such environments under reasonable costs and affordable infrastructures. Therefore, to navigate through these complex areas, combining sensors is beneficial. Common sensors used to augment/replace GNSS in complex environments include inertial measurement unit (IMU), range sensors, and vision sensors. This chapter discusses the design and implementation of tightly coupled sensor fusion of GNSS, IMU, and light detection and ranging (LiDAR) measurements to navigate in complex urban and indoor environments.

scholarly journals Performance Characterization of GNSS/IMU/DVL Integration under Real Maritime Jamming Conditions

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2954 ◽  
Author(s):  
Ralf Ziebold ◽  
Daniel Medina ◽  
Michailas Romanovas ◽  
Christoph Lass ◽  
Stefan Gewies
Keyword(s):  
Inertial Sensors ◽  
Unscented Kalman Filter ◽  
Low Cost ◽  
Primary Source ◽  
Global Navigation Satellite Systems ◽  
Measurement Unit ◽  
Doppler Velocity ◽  
Satellite Systems ◽  
Tightly Coupled ◽  
The Baltic

Currently Global Navigation Satellite Systems (GNSSs) are the primary source for the determination of absolute position, navigation, and time (PNT) for merchant vessel navigation. Nevertheless, the performance of GNSSs can strongly degrade due to space weather events, jamming, and spoofing. Especially the increasing availability and adoption of low cost jammers lead to the question of how a continuous provision of PNT data can be realized in the vicinity of these devices. In general, three possible solutions for that challenge can be seen: (i) a jamming-resistant GNSS receiver; (ii) the usage of a terrestrial backup system; or (iii) the integration of GNSS with other onboard navigation sensors such as a speed log, a gyrocompass, and inertial sensors (inertial measurement unit—IMU). The present paper focuses on the third option by augmenting a classical IMU/GNSS sensor fusion scheme with a Doppler velocity log. Although the benefits of integrated IMU/GNSS navigation system have been already demonstrated for marine applications, a performance evaluation of such a multi-sensor system under real jamming conditions on a vessel seems to be still missing. The paper evaluates both loosely and tightly coupled fusion strategies implemented using an unscented Kalman filter (UKF). The performance of the proposed scheme is evaluated using the civilian maritime jamming testbed in the Baltic Sea.

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