Flight-testing of a cooperative UGV-to-UAV strategy for improved positioning in challenging GNSS environments
TL;DR: During a set of field tests, the positioning error of a UAV that is confronted with unfavorable GNSS satellite geometry is shown to be reduced by more than five-fold through the use of ranging updates from a UGV.
About: This article is published in Aerospace Science and Technology.The article was published on 2018-11-01 and is currently open access. It has received 27 citations till now. The article focuses on the topics: Unmanned ground vehicle & Flight test.
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26 Feb 2021
TL;DR: This paper systematically reviews the advances in UAV–UGV coordination systems during the period of 2015–2020 and offers a comprehensive investigation and analysis of the recent research.
Abstract: Coordination between unmanned aerial vehicles (UAVs) and unmanned ground vehicles (UGVs) has received increasing attention in recent years. The list of successful applications of UAV–UGV coordinati...
50 citations
TL;DR: Simulation results of two refueling rendezvous situations validate that the proposed method is capable of converging to the solutions within a second, which shows great potential for real-time applications.
36 citations
TL;DR: The stability and the properties of the proposed cooperative encirclement hunting guidance algorithm are analyzed by employing Lyapunov theories, and numerical simulation results illustrate the effectiveness of achieved cooperative encircling hunting guidance strategies.
30 citations
29 Sep 2020
TL;DR: This paper demonstrates the use of a PPA device—the SCAMP vision chip—combining perception and compute capabilities on the same device for aiding in real-time navigation and control of aerial robots.
Abstract: Environments in which GPS signals cannot be received pose problems for the control and guidance of robots. These might include operations underground, underwater or in hostile GPS-denied areas. Pixel Processor Array (PPA) cameras - in conjunction with other sensors - can be used to address the problem of establishing location, tracking and control. In this paper we use a PPA - the SCAMP vision chip - to demonstrate the marriage of perception and compute capabilities on the same device for the purposes of real-time navigation and control of aerial robots. A PPA consists of a parallel array of Processing Elements (PEs), each of which features light capture, processing and storage capabilities. This allows various image processing tasks to be efficiently performed directly on the sensor itself. Within this paper we demonstrate visual odometery and target identification running sequentially on-board a single PPA vision chip at frame rates in the region of 400\,Hz. Results are given for outdoor multirotor test flights, with comparisons shown against the baseline GPS results. This capability to run multiple algorithms at adaptive rates, in conjunction with the High Dynamic Range (HDR) of the SCAMP PPA provides a sensor that is well suited to addressing the challenge of outdoor Small Unmanned Aerial Systems (SUAS) flight in GPS denied environments. HDR can be used in situations where there is a rapid transition from indoor to outdoor environments, and images in which there are significant variations in light level across a single frame. Additionally, the PPA only needs to output specific information such as the optic flow and target position, rather than having to output entire images. This significantly reduces the bandwidth required for communication between the sensor and on-board flight computer, further enabling a high frame rate and low power operation. In future applications, multiple SCAMP PPAs could be used to provide wide angle optic flow, target identification and feature tracking within minimal additional overhead penalties in terms of weight and computational requirements.
11 citations
Cites methods from "Flight-testing of a cooperative UGV..."
...This has been approached using a Unmanned Ground Vehicle (UGV) by Sivaneri and Gross (2018), a similar idea was used by Causa et al. (2018) with multiple UAS....
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TL;DR: This work aims at establishing the theoretical basis to quantify the navigation performance for different CN integration architectures, and the results show its feasibility and effectiveness.
10 citations
References
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Proceedings Article•
01 Jan 2009TL;DR: This paper discusses how ROS relates to existing robot software frameworks, and briefly overview some of the available application software which uses ROS.
Abstract: This paper gives an overview of ROS, an opensource robot operating system. ROS is not an operating system in the traditional sense of process management and scheduling; rather, it provides a structured communications layer above the host operating systems of a heterogenous compute cluster. In this paper, we discuss how ROS relates to existing robot software frameworks, and briefly overview some of the available application software which uses ROS.
8,387 citations
Book•
01 Dec 2010TL;DR: This advanced tutorial will describe the GPS signals, the various measurements made by the GPS receivers, and estimate the achievable accuracies, and focus on topics which are more unique to radio navigation or GPS.
Abstract: The Global Positioning System (GPS) is a satellite-based navigation and time transfer system developed by the U.S. Department of Defense. It serves marine, airborne, and terrestrial users, both military and civilian. Specifically, GPS includes the Standard Positioning Service (SPS) which provides civilian users with 100 meter accuracy, and it serves military users with the Precise Positioning Service (PPS) which provides 20-m accuracy. Both of these services are available worldwide with no requirement for a local reference station. In contrast, differential operation of GPS provides 2- to 10-m accuracy to users within 1000 km of a fixed GPS reference receiver. Finally, carrier phase comparisons can be used to provide centimeter accuracy to users within 10 km and potentially within 100 km of a reference receiver. This advanced tutorial will describe the GPS signals, the various measurements made by the GPS receivers, and estimate the achievable accuracies. It will not dwell on those aspects of GPS which are well known to those skilled in the radio communications art, such as spread-spectrum or code division multiple access. Rather, it will focus on topics which are more unique to radio navigation or GPS. These include code-carrier divergence, codeless tracking, carrier aiding, and narrow correlator spacing.
2,203 citations
TL;DR: The LAMBDA method as mentioned in this paper is based on the integer least square principle and requires no application-dependent restrictions or assumptions, and can be used to estimate integer GPS ambiguities.
Abstract: This paper provides an overview of the Least-squares AMBiguity Decorrelation Adjustment (LAMBDA) method for the estimation of integer GPS ambiguities. The method's performance is discussed, together with the theoretical concepts on which it is based. The method is based on the integer least-squares principle and requires no application-dependent restrictions or assumptions. The actual integer estimation is preceded by a decorrelation step in order to make it more efficient. Especially for short time spans, a large gain in efficiency is obtained. The decorrelation of the ambiguities enables one to refrain from any approximation as far as the shape of the search space is concerned; i.e., the search is performed within the ellipsoidal space induced by the covariance matrix of the float ambiguities. The decorrelated ambiguities also make it possible to scale the search space such that, to a large degree of accuracy, it contains only the k best vectors of integer ambiguities.
112 citations
01 Sep 2014
TL;DR: In this paper, a method of integrating the measurements from a LIDAR and a MEMS IMU was proposed to provide attitude, velocity position for a small UAV in an indoor frame during the outage of GNSS.
Abstract: Simultaneous Localization and Mapping (SLAM) based on LIDAR and MEMS IMU is a kind of autonomous integrated navigation technology. It can provide attitude, velocity position for a small UAV in an indoor frame during the outage of GNSS. A method of integrating the measurements from a LIDAR and a MEMS IMU was proposed in the paper. LIDAR measurements are a set of ranges and scan angles. The angle rates and accelerations from MEMS IMU are used to drive the simplified strapdown INS equations. The first step of the method is environment features extracting from the measurements of LIDAR and constructing a feature map. Then, the model of errors of LIDAR measurement due to the change of the scan plane during the attitude manoeuver is established and compensated based on aiding information from MEMS INS and the assumption about the structural indoor environment. The relative position parameters derived from environmental features delay matching algorithm and the differences of measurements of LIDAR at adjacent times are used to estimate the error of MEMS INS and MEMS sensors by a Kaiman Filter. A LIDAR/MEMS IMU prototype was designed to verify the practicability of the integrated navigation system of LIDAR and MEMS IMU. Some experiments were carried out in a room and the results demonstrated the potential use of the LIDAR/MEMS IMU integration navigation system.
104 citations
TL;DR: The optimal navigation performance of the mapper/navigator framework in the presence of timing discrepancies is analyzed, and a practical upper bound on the resulting position error is derived.
Abstract: A framework for navigation using cellular code division multiple access (CDMA) signals is studied in this paper. Theoretical lower bounds on the navigation performance using pseudorange measurements drawn from the cellular CDMA base transceiver stations (BTSs) are derived. Moreover, the navigation performance for a mapper/navigator framework is studied in the presence of timing discrepancies between the mapper and navigator. In this framework, a mapping receiver (mapper) estimates the stochastic dynamic clock biases of the BTSs and shares these estimates with a navigating receiver (navigator). The optimal navigation performance of the mapper/navigator framework in the presence of timing discrepancies is analyzed, and a practical upper bound on the resulting position error is derived. Experimental results for a ground vehicle and unmanned aerial vehicles (UAVs) are presented. The ground vehicle results show a mean distance difference of 5.51 m between the cellular CDMA-only navigation solution and a GPS navigation solution in the absence of clock bias discrepancies. The UAV results show an improvement of 10.57 m in the root-mean-square error of the cellular CDMA navigation solution, when the sector clock bias discrepancies are accounted for utilizing the statistical model relating observed clock biases from different sectors of the same BTS cell.
70 citations