scholarly journals GNSS and LNSS Positioning of Unmanned Transport Systems: The Brief Classification of Terrorist Attacks on USVs and UUVs

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 401
Author(s):  
Łukasz Lemieszewski ◽  
Aleksandra Radomska-Zalas ◽  
Andrzej Perec ◽  
Larisa Dobryakova ◽  
Evgeny Ochin

As the demand for precision positioning grows around the world and spreads across various industries, initiatives are being taken to increasingly protect Global Navigation Satellite System (GNSS) receivers from intruders of all kinds, from unintentional industrial interference to advanced GNSS spoofing systems. The timing and cost of these forthcoming satellite navigation safety efforts are difficult to decipher due to the large number of new signals and constellations being deployed. However, it is safe to say that the newly designed anti-jamming and anti-spoofing GNSS systems open up new opportunities for innovative technologies. The false acoustic signal delay is equal to the sum of the spoofer receiving antenna delay, processing delay, and propagation delay from the spoofer to the victim. The victim finds the same location as the spoofer’s receiving antenna, and receivers located in different locations will have the same XYZ. The article presents classifications of terrorist attacks of this type.

2020 ◽  
Author(s):  
Caneren Gul ◽  
Taylan Ocalan ◽  
Nursu Tunalioglu

<p>Today, traditional Precise Point Positioning (PPP) method with high-cost geodetic grade Global Navigation Satellite System (GNSS) receivers has been used commonly for surveying, navigation, geodesy, geophysics and other engineering applications where dm-cm level accuracy is required. On the other hand, while smartphones have created a growing economic market in the world, they serve positioning, navigation and timing (PNT) services in varying accuracy levels to the users besides many other facilities. One of the most significant components of the smartphones involving multi-sensors for outdoor point-positioning and navigation is the embedded GNSS chipset. Especially, the world’s first dual-frequency GNSS smartphone produced by Xiaomi in May 2018, so-called Xiaomi Mi 8, brings a new aspect to PNT applications. In this study, a smartphone with dual-frequency embedded GNSS chipset was used to analyze the performance of PPP-Ambiguity Resolution (PPP-AR) method in engineering surveys. With respect to study aim, simultaneous static GNSS observations gathered with a geodetic grade GNSS receiver and a smartphone were conducted within a test setup. The static GNSS observations were repeated for 3 days and the campaign duration was 2 hours per day at the same daily time interval. All the raw GNSS observations were converted into Receiver Independent Exchange Format (RINEX) and processed by the relative point positioning method as a reference solution initially. Later, all observations were processed by the PPP-AR method. A widely used online post-processing GNSS service, namely CSRS-PPP, which was updated in August 2018 (GPSPACE to SPARK) were employed for PPP-AR solutions. As a conclusion, we analyze the performance of the embedded dual frequency GNSS chipset and assess the feasibility of them in different engineering surveys.</p><p><strong>Keywords:</strong> Smartphone Positioning, PPP-AR, Embedded GNSS Chipset, Dual-frequency, Engineering Surveys</p>


With pursuits to furnish secure and satisfied driving, various advanced driver assistance system (ADAS) has been developed over the preceding decades. They offer a broad range of offerings such as anti-lock braking systems (ABS), lane keeping assist (LKA), blind spot facts gadget (BLIS), cruise control (CC), adaptive cruise manage (ACC), etc. Modern vehicles are outfitted with part of sensors device like radar, ultrasonic, photography camera, light detection and ranging (LIDAR), etc., and Global Navigation Satellite System (GNSS) receivers such as a Global Positioning System (GPS) receiver, to support the operation of ADAS. Connecting these systems and competencies to manipulate the actuators of the vehicles, evolves toward automatic using systems, the place vehicles are in a position to navigate themselves besides a human driver concerned. Furthermore, trends in wireless communication allow motors to be connected, both vehicle device -to-vehicle device (V2V) and vehicle unit -to- infrastructure part (V2I). The connections furnish records about the surroundings beyond the vary of sensors. For instance, being aware that the car in front of the previous vehicle is braking at its most power, approves the ego vehicle to begin braking early to avoid or mitigate a severe rear-end collision. Consequently, two linked and automated using standards have been added in the context of cooperative wise transport device (C-ITS). C-ITS includes facts and verbal exchange applied sciences into the transport systems. C-ITS strives for safer, greater efficient, and extra sustainable transport systems. Being related will increase the consciousness of cars about their surroundings. To acquire the dreams and decorate transport systems, interplay and cooperation between actors are key factors. To enable this, dependable communication is required, due to the fact that vehicles riding in automated mode can totally alternate facts with each different via wireless communication. Ultimately, those key elements and reliability extend the complexity of the system, which desires to be tested and evaluated.


Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2503
Author(s):  
Taro Suzuki ◽  
Yoshiharu Amano

This paper proposes a method for detecting non-line-of-sight (NLOS) multipath, which causes large positioning errors in a global navigation satellite system (GNSS). We use GNSS signal correlation output, which is the most primitive GNSS signal processing output, to detect NLOS multipath based on machine learning. The shape of the multi-correlator outputs is distorted due to the NLOS multipath. The features of the shape of the multi-correlator are used to discriminate the NLOS multipath. We implement two supervised learning methods, a support vector machine (SVM) and a neural network (NN), and compare their performance. In addition, we also propose an automated method of collecting training data for LOS and NLOS signals of machine learning. The evaluation of the proposed NLOS detection method in an urban environment confirmed that NN was better than SVM, and 97.7% of NLOS signals were correctly discriminated.


Author(s):  
S. Maier ◽  
T. Gostner ◽  
F. van de Camp ◽  
A. H. Hoppe

Abstract. In many fields today, it is necessary that a team has to do operational planning for a precise geographical location. Examples for this are staff work, the preparation of surveillance tasks at major events or state visits and sensor deployment planning for military and civil reconnaissance. For these purposes, Fraunhofer IOSB is developing the Digital Map Table (DigLT). When making important decisions, it is often helpful or even necessary to assess a situation on site. An augmented reality (AR) solution could be useful for this assessment. For the visualization of markers at specific geographical coordinates in augmented reality, a smartphone has to be aware of its position relative to the world. It is using the sensor data of the camera and inertial measurement unit (IMU) for AR while determining its absolute location and direction with the Global Navigation Satellite System (GNSS) and its magnetic compass. To validate the positional accuracy of AR markers, we investigated the current state of the art and existing solutions. A prototype application has been developed and connected to the DigLT. With this application, it is possible to place markers at geographical coordinates that will show up at the correct location in augmented reality at anyplace in the world. Additionally, a function was implemented that lets the user select a point from the environment in augmented reality, whose geographical coordinates are sent to the DigLT. The accuracy and practicality of the placement of markers were examined using geodetic reference points. As a result, we can conclude that it is possible to mark larger objects like a car or a house, but the accuracy mainly depends on the internal compass, which causes a rotational error that increases with the distance to the target.


2018 ◽  
Vol 6 (1) ◽  
pp. 11
Author(s):  
Jakub Machuta ◽  
Jakub Kraus

Global Navigation Satellite System (GNSS) has become an integral part of air navigation. Delay of the GNSS signal in ionospheric layer is one of the most serious problems in using GNSS. Not only accuracy but also the safety is very important in air navigation, and for that reason the augmentation of basic GNSS is used to meet higher requirements of aviation industry. This paper discusses Satellite-Based Augmentation System (SBAS) avionics with special emphasis on correction of signal delay in ionospheric layer as one of the most significant error fixes and compares it with other GNSS based on-board equipment - with basic GNSS (GPS) in terms of accuracy and with Ground-Based Augmentation System (GBAS) generally. This article should therefore show reader the differences between the methods of calculating ionospheric corrections by SBAS and GBAS and explain the reasons of these methods, taking into account the area of intended use of both systems.


Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 4059
Author(s):  
Nobuaki Kubo ◽  
Kaito Kobayashi ◽  
Rei Furukawa

The reduction of multipath errors is a significant challenge in the Global Navigation Satellite System (GNSS), especially when receiving non-line-of-sight (NLOS) signals. However, selecting line-of-sight (LOS) satellites correctly is still a difficult task in dense urban areas, even with the latest GNSS receivers. This study demonstrates a new method of utilization of C/N0 of the GNSS to detect NLOS signals. The elevation-dependent threshold of the C/N0 setting may be effective in mitigating multipath errors. However, the C/N0 fluctuation affected by NLOS signals is quite large. If the C/N0 is over the threshold, the satellite is used for positioning even if it is still affected by the NLOS signal, which causes the positioning error to jump easily. To overcome this issue, we focused on the value of continuous time-series C/N0 for a certain period. If the C/N0 of the satellite was less than the determined threshold, the satellite was not used for positioning for a certain period, even if the C/N0 recovered over the threshold. Three static tests were conducted at challenging locations near high-rise buildings in Tokyo. The results proved that our method could substantially mitigate multipath errors in differential GNSS by appropriately removing the NLOS signals. Therefore, the performance of real-time kinematic GNSS was significantly improved.


Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4948
Author(s):  
Krzysztof Czaplewski ◽  
Zbigniew Wisniewski ◽  
Cezary Specht ◽  
Andrzej Wilk ◽  
Wladyslaw Koc ◽  
...  

Satellite geodetic networks are commonly used in surveying tasks, but they can also be used in mobile surveys. Mobile satellite surveys can be used for trackage inventory, diagnostics and design. The combination of modern technological solutions with the adaptation of research methods known in other fields of science offers an opportunity to acquire highly accurate solutions for railway track inventory. This article presents the effects of work carried out using a mobile surveying platform on which Global Navigation Satellite System (GNSS) receivers were mounted. The satellite observations (surveys) obtained were aligned using one of the methods known from classical land surveying. The records obtained during the surveying campaign on a 246th km railway track section were subjected to alignment. This article provides a description of the surveying campaign necessary to obtain measurement data and a theoretical description of the method employed to align observation results as well as their visualisation.


Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4375
Author(s):  
Veton Hamza ◽  
Bojan Stopar ◽  
Tomaž Ambrožič ◽  
Goran Turk ◽  
Oskar Sterle

Global Navigation Satellite System (GNSS) technology is widely used for geodetic monitoring purposes. However, in cases where a higher risk of receiver damage is expected, geodetic GNSS receivers may be considered too expensive to be used. As an alternative, low-cost GNSS receivers that are cheap, light, and prove to be of adequate quality over short baselines, are considered. The main goal of this research is to evaluate the positional precision of a multi-frequency low-cost instrument, namely, ZED-F9P with u-blox ANN-MB-00 antenna, and to investigate its potential for displacement detection. We determined the positional precision within static survey, and the displacement detection within dynamic survey. In both cases, two baselines were set, with the same rover point equipped with a low-cost GNSS instrument. The base point of the first baseline was observed with a geodetic GNSS instrument, whereas the second baseline was observed with a low-cost GNSS instrument. The results from static survey for both baselines showed comparable results for horizontal components; the precision was on a level of 2 mm or better. For the height component, the results show a better performance of low-cost instruments. This may be a consequence of unknown antenna calibration parameters for low-cost GNSS antenna, while statistically significant coordinates of rover points were obtained from both baselines. The difference was again more significant in the height component. For the displacement detection, a device was used that imposes controlled movements with sub-millimeter accuracy. Results, obtained on a basis of 30-min sessions, show that low-cost GNSS instruments can detect displacements from 10 mm upwards with a high level of reliability. On the other hand, low-cost instruments performed slightly worse as far as accuracy is concerned.


2021 ◽  
Vol 14 (1) ◽  
pp. 44
Author(s):  
Kan Wang ◽  
Ahmed El-Mowafy ◽  
Weijin Qin ◽  
Xuhai Yang

Nowadays, integrity monitoring (IM) is required for diverse safety-related applications using intelligent transport systems (ITS). To ensure high availability for road transport users for in-lane positioning, a sub-meter horizontal protection level (HPL) is expected, which normally requires a much higher horizontal positioning precision of, e.g., a few centimeters. Precise point positioning-real-time kinematic (PPP-RTK) is a positioning method that could achieve high accuracy without long convergence time and strong dependency on nearby infrastructure. As the first part of a series of papers, this contribution proposes an IM strategy for multi-constellation PPP-RTK positioning based on global navigation satellite system (GNSS) signals. It analytically studies the form of the variance-covariance (V-C) matrix of ionosphere interpolation errors for both accuracy and integrity purposes, which considers the processing noise, the ionosphere activities and the network scale. In addition, this contribution analyzes the impacts of diverse factors on the size and convergence of the HPLs, including the user multipath environment, the ionosphere activity, the network scale and the horizontal probability of misleading information (PMI). It is found that the user multipath environment generally has the largest influence on the size of the converged HPLs, while the ionosphere interpolation and the multipath environments have joint impacts on the convergence of the HPL. Making use of 1 Hz data of Global Positioning System (GPS)/Galileo/Beidou Navigation Satellite System (BDS) signals on L1 and L5 frequencies, for small- to mid-scaled networks, under nominal multipath environments and for a horizontal PMI down to , the ambiguity-float HPLs can converge to 1.5 m within or around 50 epochs under quiet to medium ionosphere activities. Under nominal multipath conditions for small- to mid-scaled networks, with the partial ambiguity resolution enabled, the HPLs can converge to 0.3 m within 10 epochs even under active ionosphere activities.


2018 ◽  
Vol 44 (2) ◽  
pp. 36-44 ◽  
Author(s):  
Massimiliano Pepe

In recent years, the use of low cost GNSS receivers is becoming widespread due to their increasing performance in the spatial positioning, flexibility, ease of use and really interesting price. In addition, a recent technique of Global Navigation Satellite System (GNSS) survey, called Network Real Time Kinematic (NRTK), allows to obtain to rapid and accurate positioning measurements. The main feature of this approach is to use the raw measurements obtained and stored from a network of Continuously Operating Reference Stations (CORS) in order to generate more reliable error models that can mitigate the distance-dependent errors within the area covered by the CORS. Also, considering the huge potential of this GNSS positioning system, the purpose of this paper is to analyze and investigate the performance of the NTRK approach using a low cost GNSS receiver, in stop-and-go kinematic technique. By several case studies it was shown that, using a low cost RTK board for Arduino environment, a smartphone with open source application for Android and the availability of data correction from CORS service, a quick and accurate positioning can be obtained. Because the measures obtained in this way are quite noisy and, more in general, increasing with the baseline, by a simple and suitable statistic treatment, it was possible to increase the quality of the measure. In this way, this low cost architecture could be applied in many geomatics fields. In addition to presenting the main aspects of the NTRK infrastructure and a review of several types of correction, a general workflow in order to obtain quality data in NRTK mode, regardless of the type of GNSS receiver (multi constellations, single or many frequencies, etc.) is discussed.


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