scholarly journals Assessment of the Steering Precision of a Hydrographic Unmanned Surface Vessel (USV) along Sounding Profiles Using a Low-Cost Multi-Global Navigation Satellite System (GNSS) Receiver Supported Autopilot

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3939 ◽  
Author(s):  
Mariusz Specht ◽  
Cezary Specht ◽  
Henryk Lasota ◽  
Piotr Cywiński
Keyword(s):  
Global Navigation Satellite System ◽  
Low Cost ◽  
Satellite System ◽  
Navigation Satellite ◽  
Promising Alternative ◽  
Gnss Receiver ◽  
Automatic Mode ◽  
Control Precision ◽  
Global Navigation ◽  
Global Navigation Satellite

The performance of bathymetric measurements by traditional methods (using manned vessels) in ultra-shallow waters, i.e., lakes, rivers, and sea beaches with a depth of less than 1 m, is often difficult or, in many cases, impossible due to problems related to safe vessel maneuvering. For this reason, the use of shallow draft hydrographic Unmanned Surface Vessels (USV) appears to provide a promising alternative method for performing such bathymetric measurements. This article describes the modernisation of a USV to switch from manual to automatic mode, and presents a preliminary study aimed at assessing the suitability of a popular autopilot commonly used in Unmanned Aerial Vehicles (UAV), and a low-cost multi-Global Navigation Satellite System (GNSS) receiver cooperating with it, for performing bathymetric measurements in automated mode, which involves independent movement along a specified route (hydrographic sounding profiles). The cross track error (XTE) variable, i.e., the distance determined between a USV’s position and the sounding profile, measured transversely to the course, was adopted as the measure of automatic control precision. Moreover, the XTE value was statistically assessed in the publication.

scholarly journals OutFin, a multi-device and multi-modal dataset for outdoor localization based on the fingerprinting approach

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Fahad Alhomayani ◽  
Mohammad H. Mahoor
Keyword(s):  
Global Navigation Satellite System ◽  
Urban Areas ◽  
Satellite System ◽  
Reference Points ◽  
Navigation Satellite ◽  
Data Types ◽  
Entry Barrier ◽  
Promising Alternative ◽  
Global Navigation ◽  
Global Navigation Satellite

AbstractIn recent years, fingerprint-based positioning has gained researchers’ attention since it is a promising alternative to the Global Navigation Satellite System and cellular network-based localization in urban areas. Despite this, the lack of publicly available datasets that researchers can use to develop, evaluate, and compare fingerprint-based positioning solutions constitutes a high entry barrier for studies. As an effort to overcome this barrier and foster new research efforts, this paper presents OutFin, a novel dataset of outdoor location fingerprints that were collected using two different smartphones. OutFin is comprised of diverse data types such as WiFi, Bluetooth, and cellular signal strengths, in addition to measurements from various sensors including the magnetometer, accelerometer, gyroscope, barometer, and ambient light sensor. The collection area spanned four dispersed sites with a total of 122 reference points. Each site is different in terms of its visibility to the Global Navigation Satellite System and reference points’ number, arrangement, and spacing. Before OutFin was made available to the public, several experiments were conducted to validate its technical quality.

scholarly journals Design of a Multiband Global Navigation Satellite System Radio Frequency Interference Monitoring Front-End with Synchronized Secondary Sensors

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2594
Author(s):  
Aiden Morrison ◽  
Nadezda Sokolova ◽  
James Curran
Keyword(s):  
Radio Frequency ◽  
Global Navigation Satellite System ◽  
Low Cost ◽  
Satellite System ◽  
Radio Frequency Interference ◽  
Navigation Satellite ◽  
Inertial Measurement ◽  
Front End ◽  
Global Navigation ◽  
Global Navigation Satellite

This paper investigates the challenges of developing a multi-frequency radio frequency interference (RFI) monitoring and characterization system that is optimized for ease of deployment and operation as well as low per unit cost. To achieve this, we explore the design and development of a multiband global navigation satellite system (GNSS) front-end which is intrinsically capable of synchronizing side channel information from non-RF sensors, such as inertial measurement units and integrated power meters, to allow the simultaneous production of substantial amounts of sampled spectrum while also allowing low-cost, real-time monitoring and logging of detected RFI events. While the inertial measurement unit and barometer are not used in the RFI investigation discussed, the design features that provide for their precise synchronization with the RF sample stream are presented as design elements worth consideration. The designed system, referred to as Four Independent Tuners with Data-packing (FITWD), was utilized in a data collection campaign over multiple European and Scandinavian countries in support of the determination of the relative occurrence rates of L1/E1 and L5/E5a interference events and intensities where it proved itself a successful alternative to larger and more expensive commercial solutions. The dual conclusions reached were that it was possible to develop a compact low-cost, multi-channel radio frequency (RF) front-end that implicitly supported external data source synchronization, and that such monitoring systems or similar capabilities integrated within receivers are likely to be needed in the future due to the increasing occurrence rates of GNSS RFI events.

scholarly journals Effect of Nonlinear Baseline Length Constraint on Global Navigation Satellite System Compass: A Theoretical Analysis

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Yanlong Chen ◽  
Jincheng Fan ◽  
Guobin Chang ◽  
Siyu Zhang
Keyword(s):  
Global Navigation Satellite System ◽  
Low Cost ◽  
Satellite System ◽  
Baseline Length ◽  
Navigation Satellite ◽  
Angle Estimation ◽  
Length Constraint ◽  
Simple Scaling ◽  
Global Navigation ◽  
Global Navigation Satellite

GNSS (global navigation satellite system) compass is a low-cost, high-precision, and temporally stable north-finding technique. While the nonlinear baseline length constraint is widely known to be important in ambiguity resolution of GNSS compass, its direct effect on yaw angle estimation is theoretically analyzed in this work. Four different methods are considered with different ways in which the length constraint is made use of as follows: one without considering the constraints, one with simple scaling, one with indirect statistical scaling, and one with direct statistical scaling. It is found that simple scaling does not have any effect on yaw estimation; indirect and direct statistical scalings are equivalent to each other with both being able to increase the precision. The analysis and the conclusion developed in this work can go in parallel for the case of the tilt angle estimation.

Low-cost, high accuracy Global Navigation Satellite System positioning for understanding floods

2020 ◽  
Author(s):  
Hessel Winsemius ◽  
Andreas Krietemeyer ◽  
Kirsten Van Dongen ◽  
Ivan Gayton ◽  
Frank Annor ◽  
...  
Keyword(s):  
Global Navigation Satellite System ◽  
Low Cost ◽  
Smart Phone ◽  
Satellite System ◽  
Base Station ◽  
Navigation Satellite ◽  
Low Resource Settings ◽  
Low Resource ◽  
Global Navigation ◽  
Global Navigation Satellite

<p>Detailed elevation is a prerequisite for many hydrological applications. To name a few, understanding of urban and rural flood hazard and risk; understanding floodplain geometries and conveyance; and monitoring morphological changes. The accuracy of traditional Global Navigation Satellite System (GNSS) chipsets in smart phones is typically in the order of several meters, too low to be useful for such applications. Structure from Motion photogrammetry methods or Light Detection and Ranging (LIDAR), may be used to establish 3D point clouds from drone photos or lidar instrumentation, but even these require very accurate Ground Control Point (GCP) observations for a satisfactory result. These can be acquired through specialised GNSS rover equipment, combined with a multi-frequency GNSS base station or base station network, providing a Real-Time (RTK) or Post-Processing Kinematics (PPK) solution. These techniques are too expensive and too difficult to maintain for use within low resource settings and are usually deployed by experts or specialised firms.</p><p>Here we investigate if accurate positioning (horizontal and vertical) can be acquired using a very recently released low-cost multi-constellation dual-frequency receiver (ublox ZED-F9P), connected with a simple antenna and a smart phone. The setup is remarkably small and easy to carry into the field. Using a geodetic (high-grade) GNSS antenna and receiver as base station, initial results over baselines in the order of a few km with the low-cost receiver revealed a positioning performance in the centimeter domain. Currently, we are testing the solution using a smart phone setup as base station within Dar es Salaam, to improve elevation mapping within the community mapping project “Ramani Huria”. We will also test the equipment for use in GCP observations within the ZAMSECUR project in Zambia and TWIGA project in Ghana. This new technology opens doors to affordable and robust observations of positions and elevation in low resource settings.</p>

scholarly journals Performance Evaluation of Pedestrian Locations Based on Contemporary Smartphones

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Jalal Ibrahim Al-Azizi ◽  
Helmi Zulhaidi Mohd Shafri
Keyword(s):  
Performance Evaluation ◽  
Environmental Factors ◽  
Global Navigation Satellite System ◽  
Low Cost ◽  
Satellite System ◽  
Navigation Satellite ◽  
Localization Accuracy ◽  
Environment Type ◽  
Global Navigation ◽  
Global Navigation Satellite

Nowadays, a Global Navigation Satellite System (GNSS) unit is embedded in nearly every smartphone. This unit allows a smartphone to detect the user’s location and motion, and it makes functions, such as navigation, tracking, and compass applications, available to the user. Therefore, the GNSS unit has become one of the most important features in modern smartphones. However, because most smartphones incorporate relatively low-cost GNSS chips, their localization accuracy varies depending on the number of accessible GNSS satellites, and it is highly dependent on environmental factors that cause interference such as forests and buildings. This research evaluated the performance of the GNSS units inside two different models of smartphones in determining pedestrian locations in different environments. The results indicate that the overall performances of the two devices were related directly to the environment, type of smartphone/GNSS chipset, and the application used to collect the information.

scholarly journals Precise Point Positioning Algorithm for Pseudolite Combined with GNSS in a Constrained Observation Environment

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1120 ◽  
Author(s):  
Chuanzhen Sheng ◽  
Xingli Gan ◽  
Baoguo Yu ◽  
Jingkui Zhang
Keyword(s):  
High Precision ◽  
Global Navigation Satellite System ◽  
Low Cost ◽  
Estimation Algorithm ◽  
Satellite System ◽  
Navigation Satellite ◽  
Global Navigation ◽  
Point Positioning ◽  
Global Navigation Satellite ◽  
Better Than

In urban canyon environments, Global Navigation Satellite System (GNSS) satellites are heavily obstructed with frequent rise and fall and severe multi-path errors induced by signal reflection, making it difficult to acquire precise, continuous, and reliable positioning information. To meet imperative demands for high-precision positioning of public users in complex environments, like urban canyons, and to solve the problems for GNSS/pseudolite positioning under these circumstances, the Global Navigation Satellite System (GNSS) Precision Point Positioning (PPP) algorithm combined with a pseudolite (PLS) was introduced. The former problems with the pseudolite PPP technique with distributed pseudo-satellites, which relies heavily on known points for initiation and prerequisite for previous high-precision time synchronization, were solved by means of a real-time equivalent clock error estimation algorithm, ambiguity fixing, and validation method. Experiments based on a low-cost receiver were performed, and the results show that in a weak obstructed environment with low-density building where the number of GNSS satellites was greater than seven, the accuracy of pseudolite/GNSS PPP with fixed ambiguity was better than 0.15 m; when there were less than four GNSS satellites in severely obstructed circumstances, it was impossible to obtain position by GNSS alone, but with the support of a pseudolite, the accuracy of PPP was able to be better than 0.3 m. Even without GNSS, the accuracy of PPP could be better than 0.5 m with only four pseudolites. The pseudolite/GNSS PPP algorithm presented in this paper can effectively improve availability with less GNSS or even without GNSS in constrained environments, like urban canyons in cities.

scholarly journals A Low-Cost Global Navigation Satellite System Positioning Accuracy Assessment Method for Agricultural Machinery

2022 ◽  
Vol 12 (2) ◽  
pp. 693
Author(s):  
Dorijan Radočaj ◽  
Ivan Plaščak ◽  
Goran Heffer ◽  
Mladen Jurišić
Keyword(s):  
Global Navigation Satellite System ◽  
Accuracy Assessment ◽  
Low Cost ◽  
Satellite System ◽  
Base Station ◽  
Navigation Satellite ◽  
Agricultural Machinery ◽  
Positioning Accuracy ◽  
Global Navigation ◽  
Global Navigation Satellite

The high-precision positioning and navigation of agricultural machinery represent a backbone for precision agriculture, while its worldwide implementation is in rapid growth. Previous studies improved low-cost global navigation satellite system (GNSS) hardware solutions and fused GNSS data with complementary sources, but there is still no affordable and flexible framework for positioning accuracy assessment of agricultural machinery. Such a low-cost method was proposed in this study, simulating the actual movement of the agricultural machinery during agrotechnical operations. Four of the most commonly used GNSS corrections in Croatia were evaluated in two repetitions: Croatian Positioning System (CROPOS), individual base station, Satellite-based Augmentation Systems (SBASs), and an absolute positioning method using a smartphone. CROPOS and base station produced the highest mean GNSS positioning accuracy of 2.4 and 2.9 cm, respectively, but both of these corrections produced lower accuracy than declared. All evaluated corrections produced significantly different median values in two repetitions, representing inconsistency of the positioning accuracy regarding field conditions. While the proposed method allowed flexible and effective application in the field, future studies will be directed towards the reduction of the operator’s subjective impact, mainly by implementing autosteering solutions in agricultural machinery.

Detection of Intermediate Spoofing Attack on Global Navigation Satellite System Receiver Through Slope Based Metrics

2020 ◽  
Vol 73 (5) ◽  
pp. 1052-1068
Author(s):  
Abdul Malik Khan ◽  
Naveed Iqbal ◽  
Adnan Ahmed Khan ◽  
Muhammad Faisal Khan ◽  
Attiq Ahmad
Keyword(s):  
False Alarm ◽  
False Alarm Rate ◽  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
High Stakes ◽  
Gnss Receiver ◽  
Spoofing Detection ◽  
Global Navigation ◽  
Global Navigation Satellite

A spoofing attack on a global navigation satellite system (GNSS) receiver is a threat to a significant community of GNSS users due to the high stakes involved. This paper investigates the use of slope based metrics for the detection of spoofing. The formulation of slope based metrics involves monitoring correlators along with tracking correlators in the receiver's channel, which are slaved to the prompt tracking correlator. In this study, using some candidate metrics, detectors have been formed through the analysis of simulated spoofing attacks. A theoretical variance of each metric has also been calculated as a reference for the threshold. A threshold is estimated using the measured variance from the clean signals, for specific false alarm rate. By using the measured threshold, detectors are formed based on slope metrics. These detectors have been tested using TEXBAT data. The results show that the differential slope metrics have good performance. The results have also been compared with some other techniques of spoofing detection.

Sign in / Sign up

Export Citation Format

Share Document