scholarly journals Antennas as Precise Sensors for GNSS Reference Stations and High-Performance PNT Applications on Earth and in Space

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4192
Author(s):  
Stefano Caizzone ◽  
Miriam Schönfeldt ◽  
Wahid Elmarissi ◽  
Mihaela-Simona Circiu
Keyword(s):  
Performance Indicators ◽  
High Performance ◽  
Autonomous Driving ◽  
Global Navigation Satellite Systems ◽  
Space Applications ◽  
Research Issues ◽  
Satellite Systems ◽  
Open Research ◽  
Application Fields ◽  
Global Navigation Satellite

Satellite navigation is more and more important in a plethora of very different application fields, ranging from bank transactions to shipping, from autonomous driving to aerial applications, such as commercial avionics as well as unmanned aerial vehicles (UAVs). In very precise positioning, navigation, and timing (PNT) applications, such as in reference stations and precise timing stations, it is important to characterize all errors present in the system in order to account possibly for them or calibrate them out. Antennas play an important role in this respect: they are indeed the “sensor” that capture the signal in space from global navigation satellite systems (GNSS) and thereby strongly contribute to the overall achievable performance. This paper reviews the currently available antenna technologies, targeting specifically reference stations as well as precise GNSS antennas for space applications, and, after introducing performance indicators, summarizes the currently achievable performance. Finally, open research issues are identified, and possible approaches to solve them are discussed.

scholarly journals Seamless Vehicle Positioning by Lidar-GNSS Integration: Standalone and Multi-Epoch Scenarios

2021 ◽  
Vol 13 (22) ◽  
pp. 4525
Author(s):  
Junjie Zhang ◽  
Kourosh Khoshelham ◽  
Amir Khodabandeh
Keyword(s):  
Autonomous Driving ◽  
Measurement Model ◽  
Urban Environments ◽  
Global Navigation Satellite Systems ◽  
High Definition ◽  
Satellite Systems ◽  
The Road ◽  
Gnss Receivers ◽  
Vehicle Positioning ◽  
Global Navigation Satellite

Accurate and seamless vehicle positioning is fundamental for autonomous driving tasks in urban environments, requiring the provision of high-end measuring devices. Light Detection and Ranging (lidar) sensors, together with Global Navigation Satellite Systems (GNSS) receivers, are therefore commonly found onboard modern vehicles. In this paper, we propose an integration of lidar and GNSS code measurements at the observation level via a mixed measurement model. An Extended Kalman-Filter (EKF) is implemented to capture the dynamic of the vehicle movement, and thus, to incorporate the vehicle velocity parameters into the measurement model. The lidar positioning component is realized using point cloud registration through a deep neural network, which is aided by a high definition (HD) map comprising accurately georeferenced scans of the road environments. Experiments conducted in a densely built-up environment show that, by exploiting the abundant measurements of GNSS and high accuracy of lidar, the proposed vehicle positioning approach can maintain centimeter-to meter-level accuracy for the entirety of the driving duration in urban canyons.

Computer Modelling of Autonomous Satellite Navigation Characteristics on Geostationary Orbit

2019 ◽  
pp. 311-338
Author(s):  
Fedir Shyshkov ◽  
Valeriy Konin
Keyword(s):  
Computer Modelling ◽  
Satellite Navigation ◽  
Research Data ◽  
Global Navigation Satellite Systems ◽  
Geostationary Orbit ◽  
Space Environment ◽  
Space Applications ◽  
Satellite Systems ◽  
Spacecraft Navigation ◽  
Global Navigation Satellite

Satellite systems are a fast-developing and broad field of study. The use of global navigation satellite systems for relatively autonomous spacecraft navigation holds a lot of interest for researchers. It is extremely expensive to research space applications as live experiments. Therefore, computer modelling comes in handy when there is a need to analyze important factors in space environment. The chapter describes the radionavigation field model that uses the off-nadir satellites. This model allows estimation of the availability and accuracy characteristics of autonomous satellite navigation in space up to the geostationary orbit in order to provide the necessary research data.

scholarly journals Integrity and Collaboration in Dynamic Sensor Networks

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2400 ◽  
Author(s):  
Steffen Schön ◽  
Claus Brenner ◽  
Hamza Alkhatib ◽  
Max Coenen ◽  
Hani Dbouk ◽  
...  
Keyword(s):  
Sensor Networks ◽  
Urban Areas ◽  
Research Training ◽  
Training Group ◽  
Autonomous Driving ◽  
Global Navigation Satellite Systems ◽  
Satellite Systems ◽  
Global Navigation Satellite ◽  
Map Data ◽  
Dynamic Sensor Networks

Global Navigation Satellite Systems (GNSS) deliver absolute position and velocity, as well as time information (P, V, T). However, in urban areas, the GNSS navigation performance is restricted due to signal obstructions and multipath. This is especially true for applications dealing with highly automatic or even autonomous driving. Subsequently, multi-sensor platforms including laser scanners and cameras, as well as map data are used to enhance the navigation performance, namely in accuracy, integrity, continuity and availability. Although well-established procedures for integrity monitoring exist for aircraft navigation, for sensors and fusion algorithms used in automotive navigation, these concepts are still lacking. The research training group i.c.sens, integrity and collaboration in dynamic sensor networks, aims to fill this gap and to contribute to relevant topics. This includes the definition of alternative integrity concepts for space and time based on set theory and interval mathematics, establishing new types of maps that report on the trustworthiness of the represented information, as well as taking advantage of collaboration by improved filters incorporating person and object tracking. In this paper, we describe our approach and summarize the preliminary results.

Computer Modelling of Autonomous Satellite Navigation Characteristics on Geostationary Orbit

2021 ◽  
pp. 425-452
Author(s):  
Fedir Shyshkov ◽  
Valeriy Konin
Keyword(s):  
Computer Modelling ◽  
Satellite Navigation ◽  
Research Data ◽  
Global Navigation Satellite Systems ◽  
Geostationary Orbit ◽  
Space Environment ◽  
Space Applications ◽  
Satellite Systems ◽  
Spacecraft Navigation ◽  
Global Navigation Satellite

Satellite systems are a fast-developing and broad field of study. The use of global navigation satellite systems for relatively autonomous spacecraft navigation holds a lot of interest for researchers. It is extremely expensive to research space applications as live experiments. Therefore, computer modelling comes in handy when there is a need to analyze important factors in space environment. The chapter describes the radionavigation field model that uses the off-nadir satellites. This model allows estimation of the availability and accuracy characteristics of autonomous satellite navigation in space up to the geostationary orbit in order to provide the necessary research data.

scholarly journals GNSS-R with Low-Cost Receivers for Retrieval of Antenna Height from Snow Surfaces Using Single-Frequency Observations

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5536 ◽  
Author(s):  
Simone Rover ◽  
Alfonso Vitti
Keyword(s):  
Low Cost ◽  
Test Site ◽  
Global Navigation Satellite Systems ◽  
Single Frequency ◽  
Satellite Systems ◽  
Management Plans ◽  
Gnss Reflectometry ◽  
Application Fields ◽  
Global Navigation Satellite ◽  
Gnss Observations

Snowpack is an important fresh water storage; the retrieval of snow water equivalents from satellite data permits to estimate potentially available water amounts which is an essential parameter in water management plans running in several application fields (e.g., basic needs, hydroelectric, agriculture, hazard and risk monitoring, climate change studies). The possibility to assess snowpack height from Global Navigation Satellite Systems (GNSS) observations by means of the GNSS reflectometry technique (GNSS-R) has been shown by several studies. However, in general, studies are being conducted using observations collected by continuously operating reference stations (CORS) built for geodetic purposes and equipped with geodetic-grade instruments. Moreover, CORS are located on sites selected according to criteria different from those more suitable for snowpack studies. In this work, beside an overview of key elements of GNSS reflectometry, single-frequency GNSS observations collected by u-blox M8T GNSS receivers and patch antennas from u-blox and Tallysman have been considered for the determination of antenna height from the snowpack surface on a selected test site. Results demonstrate the feasibility of GNSS-R even with non-geodetic-grade instruments, opening the way towards diffuse GNSS-R targeted applications.

scholarly journals GPS/Galileo Multipath Detection and Mitigation Using Closed-Form Solutions

2009 ◽  
Vol 2009 ◽  
pp. 1-20 ◽  
Author(s):  
Khaled Rouabah ◽  
Djamel Chikouche
Keyword(s):  
High Performance ◽  
High Accuracy ◽  
Global Navigation Satellite Systems ◽  
Line Of Sight ◽  
Satellite Systems ◽  
Closed Form Solutions ◽  
Gnss Positioning ◽  
Simulation Results ◽  
Multipath Detection ◽  
Global Navigation Satellite

We propose an efficient method for the detection of Line of Sight (LOS) and Multipath (MP) signals in global navigation satellite systems (GNSSs) which is based on the use of virtual MP mitigation (VMM) technique. By using the proposed method, the MP signals' delay and coefficient amplitudes can be efficiently estimated. According to the computer simulation results, it is obvious that our proposed method is a solution for obtaining high performance in the estimation and mitigation of MP signals and thus it results in a high accuracy in GNSS positioning.

scholarly journals ASSESSMENT OF CAR COLLABORATIVE POSITIONING WITH UWB AND VISION

2021 ◽  
Vol XLIII-B1-2021 ◽  
pp. 221-227
Author(s):  
A. Masiero ◽  
C. Toth ◽  
J. Gabela ◽  
G. Retscher
Keyword(s):  
Autonomous Driving ◽  
Global Navigation Satellite Systems ◽  
Navigation Systems ◽  
Common People ◽  
Positioning Systems ◽  
Satellite Systems ◽  
Vehicle To Vehicle ◽  
The Absolute ◽  
Global Navigation Satellite ◽  
Consumer Devices

Abstract. During the last decades the role of positioning and navigation systems is drastically changed in the everyday life of common people, influencing people behavior even multiple times each day. One of the most common applications of this kind of systems is that of terrestrial vehicle navigation: the use of GPS in the automotive navigation sector started thirty years ago, and, nowadays, it commonly assists drivers in reaching most of their non-standard destinations. Despite the popularity of global navigation satellite systems (GNSS), their usability is quite limited in certain working conditions, such as in urban canyons, in tunnels and indoors. While the latter case is typically not particularly interesting for the automotive sector, the first two scenarios represent important cases of interest for automotive navigation. In addition to the market request for increasing the usability of navigation systems on consumer devices, the recent increasing eagerness for autonomous driving is also attracting a lot of researchers’ attention on the development of alternative positioning systems, able to compensate for the unavailability or unreliability of GNSS. In accordance with the motivations mentioned above, this paper focuses on the development of a positioning system based on collaborative positioning between vehicles with UltraWide-Band devices and vision. To be more specific, this work focuses on assessing the performance of the developed system in successfully accomplishing three tasks, associated to different levels of gathered information: 1) assessing distance between vehicles, 2) determining the vehicle relative positions, 3) estimating the absolute car positions. The obtained results show that a) UWB can be reliably used (error of few decimeters error) to assess distances when vehicles are relatively close to each other (e.g. less than 40 m), b) the combination of UWB and vision allows to obtain good results in the computation of relative positions between vehicles, c) UWB-based collaborative positioning can be used for determining the absolute vehicle positions if a sufficient number of UWB range measurements can be ensured (sub-meter error for vehicles connected with a static UWB infrastructure, whereas error at meter level for those exploiting only vehicle-to-vehicle UWB communications).

Novel Integrity Concept for CAT III Precision Approaches and Taxiing: Extended GBAS (E-GBAS)

2011 ◽  
Vol 64 (4) ◽  
pp. 695-710 ◽  
Author(s):  
Wolfgang Schuster ◽  
Washington Ochieng
Keyword(s):  
Measurement Errors ◽  
High Performance ◽  
Performance Monitoring ◽  
Global Navigation Satellite Systems ◽  
Monitoring Scheme ◽  
Satellite Systems ◽  
Accuracy Requirement ◽  
Ground Station ◽  
Full Benefit ◽  
Global Navigation Satellite

Future air navigation envisages increased use of Global Navigation Satellite Systems (GNSS) together with advanced communications and surveillance technologies to facilitate the required increase in capacity, efficiency and safety without adversely impacting the environment. The full benefit of GNSS is expected from its ability to support en-route to en-route or gate-to-gate air navigation. This presents challenges particularly for the phases of flight with stringent required navigation performance. Significant work has so far been devoted to the phases of flight up to CAT I. However, more work is required for CAT III precision landing (with an accuracy requirement at the metre level) and taxiing (with an accuracy requirement at sub-metre level) and both with very high integrity and continuity requirements. The main limitation in using GBAS for CAT III landings is the potential decorrelation of the measurement errors between the GBAS ground station (GGS) and the user. The threats in this respect are the atmospheric anomalies. Periods of strong solar activity can cause large local spatial and temporal gradients in the delays induced on the GNSS signals by the ionosphere. The local nature of the effects results in significant decorrelation between GGS measurements and the user. Therefore, a reliable ground based ionospheric anomaly monitoring scheme is required to guarantee integrity.This paper critically reviews state-of-the-art monitors, identifies their limitations and addresses them by proposing a high-performance monitoring scheme for the ionosphere. Preliminary analyses suggest that the proposed scheme has the potential to enable GNSS to meet the navigation requirements for CAT III and taxiing.

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