Many civil GNSS (Global Navigation Satellite System) applications need secure, assured information for asset tracking, fleet management and the like. But there is also a growing demand for geosecurity location- -based services. Unfortunately, GNSS is vulnerable to malicious intrusion and spoofing. How can users be sure that the information they receive is authentic? Spoofing is the transmission of matched-GNSS-signal- -structure interference in an attempt to commandeer the tracking loops of a victim receiver and thereby manipulate the receiver’s timing or navigation solution. A spoofer can transmit its counterfeit signals from a stand-off distance of several hundred meters, or it can be co-located with its victim. Spoofing attacks can be classified as simple, intermediate, or sophisticated in terms of their effectiveness and subtlety. In an intermediate spoofing attack, a spoofer synchronizes its counterfeit signals with the authentic GNSS signals, so they are code-phase-aligned at the target receiver. In this paper, authors consider the antispoofing algorithms based on finding statistical anomalies in the basic parameters of the satellite signals. At the stage of learning, the system of antispoofing explores the statistical properties of signals and at the phase of spoofing detection, the system used thresholds characteristics of statistical anomalies. The excess of the threshold characteristics provides a basis for probabilistic decision on the presence of spoofing

In the general case measurements performed in navigation are those of position coordinates − points on the trajectory, and trajectory derivatives − speed vector and acceleration vector. Due to the occurrence of systematic and random errors, there is no full conformity of results obtained from measurements by various navigational instruments and systems in the mathematical model of the process of navigation, as well as in specific measurement models. This study attempts to compare trajectories, speeds and accelerations determined by different measurement tools (navigational equipment and systems). The results may be used in an analysis of measurement reliability and of the correct performance of navigational systems and equipment. A comparison of various sources of information also allows to detect and identify systematic errors, so that, consequently, mathematical models of specific phenomena and processes can be verifie

Satellite Navigation Systems (SNSs), the GPS system in particular, were available to civilian users from the beginning. The first community interested was the maritime one, for both professional and recreational purposes. Marine navigation distinguishes between five major phases, among those the port approach and operation in restricted waters and the marine navigation in the port. SNSs, today the GPS system and its differential mode DGPS, and Satellite Based Augmentation Systems (SBAS) as EGNOS and WAAS, provide a wide range of applications in both these phases, e.g. coupling SNS receivers with dedicated sensors installed on the ship’s bridge, e.g. AIS, aid in the berthing and docking of large vessels, by means of the position and the heading reference systems. In maritime restricted area, the SNS position accuracy can be decreased when the masking elevation angle causing by the obstacles is for the user on the ship greater than masking angle of observer’s receiver. This diminution depends on among other things the ship course, observer’s latitude, the height of the obstacle, the distance between the observer and the obstacle, here coast side. Additionally, the problem of availability of the integrity information to users and performances, and future use of the GLONASS system after modernization, Galileo and Compass systems actually under construction, new SBASs, the next DGPS and DGLONASS reference stations, and Eurofix with differential corrections to GPS including integrity messages in coastal navigation are described in the paper

The paper presents an overview of methods for detecting the spoofing of GNSS open service code signals illustrated with the example of C/A GPS signals. GNSS signal spoofing is an attack method where a signal is transmitted that appears authentic but it induces the receiver under attack to compute an erroneous navigation solution, time, or both. Usage of commercially available satellite compasses and two antennas systems for the detection of such threat is described in detail.

For disintegration process control we need a quantity that respects objectively rock-disintegrating tool interaction with the elimination of human factor. From this, basic requirements for the evaluation quantity given below follow: is available in advance or at the moment of disintegration; minimises the influence of human factor on the resultant effect; evaluates objectively the disintegration process. A measure of efficiency of any disintegration process is the consumption of energy usually related to the unit volume of disintegrated rock; on the basis of analysis done theoretical and practical researches orientated towards the disintegration processes and the verification of objectivity when used in situ (in drilling and tunnelling), at present it is minimised specific volume energy that is the most objective evaluation quantity. This quantity has a general validity for dispersion processes, and thus its use even for the evaluation of diggability on the digging wheel of excavator has a rational basis. In connection with the GIS application for controlling the extracted quantity, an optimal tool is offered for the maximum efficiency of excavation process.

Many civil GNSS (Global Navigation Satellite System) applications need secure, assured information for asset tracking, fleet management and the like. But there is also a growing demand for geosecurity locationbased services. Unfortunately, GNSS is vulnerable to malicious intrusion and spoofing. How can users be sure the information they receive is authentic? Spoofing is the transmission of matched-GNSS-signalstructure interference in an attempt to commandeer the tracking loops of a victim receiver and thereby manipulate the receiver’s timing or navigation solution. A spoofer can transmit its counterfeit signals from a stand-off distance of several hundred meters or it can be co-located with its victim. Spoofing attacks can be classified as simple, intermediate, or sophisticated in terms of their effectiveness and subtlety. In an intermediate spoofing attack, a spoofer synchronizes its counterfeit signals with the authentic GNSS signals so they are code-phase-aligned at the target receiver. In this paper we consider the anti-spoofing algorithms based on spoofing detection via Dual-Receiver.

The article presents a method of stochastic modeling of a GNSS position error. Pre-liminary results of DGPS error simulation are presented, a simulation algorithm is de-scribed as well as its application in sea traffic engineering research.

The paper presents the results of empirical study on the precision of public transport vehicles' localization in areas with different degrees of urbanization. The pa-per also discusses the premises for the creation of fleet management system for public transport and typical configurations of such systems. Particular attention is devoted to the localization of public transport vehicles in the street network. Finally, the paper presents the approach to city bus localization adopted in a project of the system for public transport management in Warsaw.

The vessel’s position and its heading are necessary to display its shape on an electronic chart. This paper describes an experimenal determination of heading accuracy. There are two types of pilot navigation systems: stationary and portable, and they may use various sources of heading data. Particularly a gyrocompass and GPS compass were tested and verified by the heading determined by two RTK receivers.

The paper presents an analysis of the current GNSS constellation geometry (comprising 28 active GPS satellites) performed in the Port of Świnoujście. The geome-try disturbances resulting from the harbour infrastructure were taken into consideration and values of mask angles were determined depending on ship’s position in the fairway and GPS antenna location. On this basis the availability of GPS position in the Port of Świnoujście was evaluated. The statistical analysis of satellites locations’ impact on the geometrical quality of GNSS receiver’s position was made after grouping available satellites’ parameters into four main sectors (N, E, S, and W).

The paper presents an accuracy evaluation analysis of the ship;s heading measured between two GPS antennas of automatic GPS and code DGPS type. The usefulness of the above mentioned GPS techniques for the vessel's navigation and piloting systems in confined waters has also been evaluated.

Position determination of Global Navigation Satellite Systems (GNSS) depends on the stability and accuracy of the measured time. However, since satellite vehicles (SVs) travel at velocities significantly larger than the receivers and, more importantly, the electromagnetic impulses propagate through changing gravitational poten- tials, enormous errors stemming from relativity-based clock offsets would cause a position error of about 11 km to be accumulated after one day. Based on the premise of the constancy of light, two major relativistic effects are described: time dilation and gravitational-frequency shift. Following the individual interests of the author, formulas of both are scrupulously derived from general- and special-relativity theory principles; moreover, in the penultimate section, the equations are used to calculate the author’s own numerical values of the studied parameters for various GNSSs and one Land Navigation Satellite System (LNSS).

One of the main problems in modern navigation of both manned and unmanned transport systems is that of transport safety. Differential GNSS technology has been used to improve the accuracy of transport positioning, in which position is calculated relative to a fixed reference station with a known position XYZ. Unfortunately, GNSS is vulnerable to malicious intrusion. GNSS signals and/or correction signals from the reference station can be spoofed by false signals, and special receivers have been used to provide defenses against such attacks. But how can the roving receiver (i.e. the user) be sure that the information they receive is authentic? Spoofing is the transmission of a matched-GNSS-signal-structure and/or signals to a reference station in order to cause interference and attempt to commandeer the tracking loops of a victim receiver, thereby allowing manipulation of the receiver’s timing or navigation solution. A spoofer can transmit its counterfeit signals from a stand-off distance of several hundred meters, or it can be co-located with its victim. In this article we consider the principles of spoofing detection using Differential GNSS, in which a correction signal from the reference station is used for the detection of spoofing

Signals from Global Navigation Satellite Systems are the primary source for Position, Navigation and Time (PNT) information onboard any vessel today. As these signals are prone to interference, a maritime backup system is needed to provide reliable PNT data, R(anging)-Mode is such a system. It utilizes existing maritime radio beacons or base stations of the Automatic Identification System (AIS) by adding ranging components to the legacy signals. The first modified radio beacons transmit medium frequency (MF) R-Mode signals in northern Germany. This paper has described the current state of the authors’ research and development activities at the receiver level for MF R-Mode signals. The receiver platform has been introduced, which was based on off-theshelf components and the implemented algorithms for distance estimation have been explained. Furthermore, the results of the first ranging measurements have been presented, which have shown the general suitability of the R-Mode technology as a source for maritime positioning and timing data.