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We describe the developments of a propagation receiver for the Alphasat Q-band copolar beacon that is expected to be operational from April 2015. The receiver link budget and the expected attenuation dynamic range are presented. The RF hardware and a simplified approach to one axis only antenna pointing system solution are detailed. Solutions to acquire and detect the beacon signal are discussed....
We consider GNSS meaconing detection with multiple COTS receivers. Recently proposed detectors that use the receivers' reported positions are extended, to allow for the use of additional metrics, such as pseudo range. An actual meaconing attack is performed to evaluate the performance of the proposed detectors, using either position or pseudo range data. The attack is performed with a GPS simulator,...
The localization, that allows to precisely know the orientation and position of a system in the environment, is still challenging in urban environments due to satellite occlusion. This phenomenon reduces the data redundancy and provides bad satellite geometry and reflected signals, called multipaths, that distort the measurements and make them erroneous. The RAIM method, integrated in most GPS receivers,...
Global Positioning System (GPS) carrier-phase (CP) time transfer, as a widely accepted high-precision time transfer method, frequently shows a data-batch boundary discontinuity of up to 1 ns, because of the inconsistency of the phase ambiguities between two consecutive data batches. To eliminate the data-batch boundary discontinuity, several techniques have been proposed in recent years. The question...
Ranging signals in the urban environment suffer from significant attenuation and additive errors caused by reflections. Special design considerations for ranging-based positioning systems that operate in the Urban Canyon are presented. The tradeoff between acquisition sensitivity and acquisition time is presented. The integrity of the measurements is improved by verifying that the signals exhibit...
Vehicle-Mounted Earth Station (VMES) terminals are new terminals and interference from these terminals is time varying. Recommendations (Recs.) ITU-R S.1857 and S.2029 were developed to assess and limit the time-varying interference from these terminals. In this paper we consider the effects of interference due to motion-induced antenna pointing errors using the traditional "worst-case"...
As an important simulation platform for wireless communication, OPNET Modeler implements the wireless channel by 14 wireless channel pipeline stages for terrestrial mobile communication system, but does not support the proper realization of Long Term Evolution (LTE) based satellite communication system. In this paper, we analyze the differences between these two communication systems from the aspect...
In this paper, we consider the problem of interference mitigation in GNSS navigation. In this work, we introduce the novel concept of multi-beamforming as our approach to multi-channel receiver design in order to enable dynamic tracking of satellite vehicles within the field of view. Special attention is given to beamwidth control. The receiver is equiped with two stages of operation. In the first...
A precise position and attitude information is essential for autonomous driving of any vehicle. Low-cost GNSS receivers and antennas can provide a precise attitude and drift-free position information. However, severe code multipath, frequent half cycle slips and losses of lock might temporarily reduce the accuracy. Inertial sensors are robust to GNSS signal interruption and very precise over short...
The market trends towards the use of smaller dish antennas for TV satellite receivers, as well as the growing density of broadcasting satellites in orbit require the application of robust adjacent satellite interference (ASI) cancellation algorithms at the receivers. The wider beamwidth of a small size dish and the growing number of satellites in orbit impose an overloaded scenario, i.e., a scenario...
Civilian GPS signals are currently used in many critical applications, such as precise timing for power grids and telecommunication networks. Spoofing may cause their improper functioning. It is a threat which emerges with the growing availability of GPS constellation simulators and other devices which may be used to perform such attack. Development of the effective countermeasures, covering detection...
With the increase in the international satellite navigation system, satellite navigation frequency resources are already in short supply, and due to commercial, disaster relief and other reasons, the design of the navigation signals and use are more sophisticated, complex. In the same basic bandwidth, there may be multi-navigation signals, by analyzing the intrasystem interference, the designed reasonableness...
In urban environment, Global Navigation Satellite System (GNSS) signals are impaired by non-line-of-sight fading conditions and by the presence of potential sources of electromagnetic disturbance. This paper analyzes the impact of the wireless propagation medium and aggregate network interference by measuring the degradation of the acquisition performance expressed in terms of receiver operating characteristics...
A multi-constellation GNSS RF front-end with an integer-N PLL has been implemented for Compass and GPS applications in a 0.35μm SiGe BiCMOS process. A LNA in common-emitter topology with a noise figure of 1.7dB is integrated on the chip. An inter-N PLL based frequency synthesizer is designed to generate different local oscillator (LO) signals for down-converting the received Compass/GPS signals in...
A non-coherent vector delay/frequency-locked loop architecture for GNSS receivers is proposed. Two dynamics models are considered: PV (position and velocity) and PVA (position, velocity, and acceleration). In contrast with other vector architectures, the proposed approach does not require the estimation of signals amplitudes. Only coarse estimates of the carrier-to-noise ratios are necessary.
It is known that signal acquisition can be treated as a two-dimensional search and all the possible results are located in the search plane as different cells. In this paper, the theoretical expression of the cross-ambiguity function (CAF) is analyzed, and the property of the approximate expression is exploited, while it is seldom addressed in previous GNSS receiver architectures. Based on the property...
Pre-correlation differential detection (PDD) scheme is studied for global navigation satellite systems (GNSS) receiver design. By performing a differential detection at the chip or sample level before correlation process, the effect of both data and residual carrier is eliminated which in turn allows for frequency independent code phase acquisition. Hence the search space and computational complexity...
High-accuracy Total Electron Content (TEC) measurements are important for several applications, including GNSS time transfer with accuracies better than 10 ns. In addition, it is important to provide uncertainty estimates to algorithms that use the TEC measurements. Dual-frequency TEC errors are dominated by satellite inter-frequency biases, satellite inter-code biases, receiver inter-frequency biases,...
Criteria for intermodulation products falling within the receiver of an X-band satellite earth terminal are historically governed by MIL-STD-188-164 and STANAG 4484. These specifications limit received intermodulation products from a simple two-tone transmitter measurement. X-band earth terminals that satisfy the challenging criteria qualify for multi-carrier operation. This paper investigates the...
This article describes a GNSS monitoring station over the L band. The monitoring is performed in two different ways: over the signal's spectrum by means of statistical analysis and in the range domain determining the horizontal protection level. The horizontal protection level ensures that the user's location is within a certain range with a certain probability and is used as input in decision making...
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