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In this paper results of research on RTK (Real Time Kinematic) technique used to develop small and lightweight receiver of GNSS (Global Navigation Satellite System) signals is presented. Experiments with such receivers show that they are able to deliver good quality position estimation of micro aerial vehicles in 3D space during a flight. The standard deviation of the position measurement is less...
Satellite navigation is very widespread in civil society; many devices and services exploit this technology and several systems are in use or in development phase. GNSS receiver, embedded in devices used in daily life (smartphones, cars and so on), works in several conditions and operational scenarios. Ensuring good positioning accuracy is challenging, especially in environment where receiver measurements...
Cooperative maneuvers between trains like platooning or dynamic merging and splitting of train sets have the potential to increase efficiency and flexibility in railway operations. However, such maneuvers are safety critical and require continuously accurate relative position and velocity information. This information cannot be provided by infrastructure based train control systems like the European...
The problem of relative positioning is introduced and some solutions are proposed. The topic is studied as applied to the Global Positioning System (GPS). Unlike usual GPS positioning, in relative positioning, the navigator's location in some Earth-bound coordinates is not the desired result, but instead, the position of one GPS user relative to another. The relative position is given in user-centered...
Global Positioning System (GPS) is the emerging technology extending its applications in the field of surveying, navigation, military etc., and these applications demands multiple levels of accuracy ranging from tens of meters to sub-millimetre level. Hence there is a need to develop systems, methods and a technique to meet the demand of high accuracy.GPS provides its services in two different standards,...
The Global Navigation Satellite System (GNSS) has been widely used by militaries as well as civilians. Generally, the locating accuracy is high, but the system is lack of immunity against spoofing attack, which may deceive the receiver into error positioning. In order to deal with the problem, a maximum particle weight monitoring scheme based on particle filter (PF) is proposed for spoofing detection...
This paper proposes a weighted total least squares approach based on both pseudorange and carrier phase measurements. The paper makes use of the weighted total least squares solution to solve the global positioning system (GPS) navigation equation determining the user position. The total least squares estimation considers both measurements vector and observable data matrix errors which common least...
Quantification of the multipath-induced error in GNSS code-based range measurements is usually entrusted to curves as the multipath error envelope (MEE). Although very useful for comparative evaluations, these metrics do not include any realistic information on the propagation channel statistical characterization and consequently cannot be used to quantify the multipath error in an absolute way. A...
Many well-known and efficient technologies for satellite-based localization in open space there exist; however, their accuracy and availability depend on several factors, such as the characteristics of the devices used, the surrounding environment, and the distance from reference stations. In the ALARP (A railway automatic track warning system based on distributed personal mobile terminals) system,...
Multipath error analysis under realistic conditions is often a necessary part of receiver performance assessment. To evaluate the effects of multipath it is necessary to isolate it form other errors. This paper re-visits the use of code-minus-carrier phase measurements for multipath error isolation and describes the steps necessary to get an output that can be easily analyzed during Global Navigation...
DGPS transmits pseudorange correction (PRC) to user receivers to improve the position precision. Spoofer generates a fake GPS signal and transmits this signal to the target receiver. If a DGPS reference receiver is spoofed, not only reference position but also many user positions are affected. Moreover, DGPS reference station is easy to spoof because its position is known and fixed. Therefore, the...
A dual one-way ranging system (DOWR) can provide very high precision ranging between two carrier phase transceiver-receiver systems. In microwave ranging system, the accuracy of inter-satellite ranging is mainly limited by the stability of the oscillator and the accuracy of phase measurement. In K/Ka band, the Micron level ranging requests that the phase measure achieves 0.0006rad measurement precision...
A simulation model will be described and employed to study the propagation channel of the Global Positioning System. Initially, a digital elevation model, building databases, and a vegetation model are processed to generate azimuth-elevation maps of path states (clear, shadowed and blocked) for a large number of observers. At each simulation step, satellite positions are updated using an orbit predictor...
A basic requirement for a satellite's formation is the precise knowledge of the spacecraft's relative configuration. The design of the navigation subsystem is significantly affected by this peculiar issue: in fact, the accuracy required for the fulfillment of the formation tasks is much greater than the one usually required for a single satellite.
The modification of the longwave ASF (Additional Secondary Factor) is the key to ensure the precision of longwave navigation system, but at present there does not exist the effective way to measure the ASF, because of the effect of the geography. So the paper put forward the way that can measure the ASF, resulted from the theory of wavelet and least square, based on the integrated longwave and microwave...
GPS (Global positioning System) is a 3D positioning system using space satellites. Recently, the use of GPS in the city as the navigation system is rising continuously. However the measurement error is large when the receiver is used near the buildings such as in urban canyon. This reason is that the receiver is not able to measure a pseudo range accurately because of receiving reflected wave (multipath)...
Multi-path reflections can cause GPS receiver devices to mis-calculate their location. Errors due to multi-path will tend to bias the position estimate from the true value. The redundancy of satellites can be utilized to identify a single source of error. The estimated residual error is an artifact of the least squares estimate process. After the estimate is computed, the residual estimate error from...
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