One of the main vulnerabilities GNSS receivers is their exposure to intentional or unintentional jamming signals, which could even cause service unavailability. Several alternatives counteract these effects were proposed in literature, being most promising those based on multiple antenna architectures. This specially case for high-grade used applications requiring reliability and robustness. article provides an overview possible receiver architectures encompassing arrays associated signal...

In this letter, we obtain the maximum likelihood estimator of position in framework global navigation satellite systems. This theoretical result is basis a completely different approach to positioning problem, contrast conventional two-step estimation, consisting estimating synchronization parameters in-view satellites and then performing estimation with that information. To authors' knowledge, novel copes signal fading, it mitigates multipath jamming interferences. Besides, concept...

This paper addresses the estimation of code-phase (pseudorange) and carrier-phase direct signal received from a direct-sequence spread-spectrum satellite transmitter. The is by an antenna array in scenario with interference multipath propagation. These two effects are generally limiting error sources most high-precision positioning applications. A new estimator code- carrier-phases derived using simplified model maximum likelihood (ML) principle. consists essentially gathering all signals,...

Multipath is known to be one of the most dominant sources accuracy degradation in satellite-based navigation systems. may cause biased position estimates that could jeopardize high-precision applications. This paper considers problem tracking time-variant synchronization parameters both line-of-sight signal (LOSS) and its multipath replicas. In particular, proposed algorithm tracks time-delays, amplitudes, phases proposes a procedure extract Doppler shifts from complex amplitudes. However,...

It is known that satellite radiolocalization was born in the military environment and originally conceived for defense purposes. Nevertheless, commercial explosion (dated to 20 years ago) of global positioning system (GPS) civil market (automotive, tourism, etc.) significantly changed original perspectives this technology. Another big change expected when other navigation systems (GNSSs) such as European Galileo or Chinese COMPASS become operational commercial. In fact, modern GNSSs are...

Carrier synchronization is a fundamental stage in the receiver side of any communication or positioning system. Traditional carrier phase tracking techniques are based on well-known phase-locked loop (PLL) closed-loop architectures, which still methods choice modern receivers. Those well understood, easy to tune, and perform under benign propagation conditions, but their applicability seriously compromised harsh environments, where signal may be affected by high dynamics, shadowing, strong...

<h3>Abstract</h3> Taking the work conducted by global navigation satellite system (GNSS) software-defined radio (SDR) working group during last decade as a seed, this contribution summarizes, for first time, history of GNSS SDR development. This report highlights selected implementations and achievements that are available to public or influenced general development SDR. Aspects related standardization process intermediate-frequency sample data metadata discussed, an update Institute...

This work addresses the signal acquisition problem using an array of antennas in general framework Global Navigation Satellite Systems (GNSS) receivers. We propose a statistical approach, Neyman-Pearson (NP) detection theory and generalized likelihood ratio test (GLRT), to obtain new detector which is able mitigate temporally uncorrelated interferences even if unstructured moderately uncalibrated. The key feature assumption arbitrary unknown covariance noise matrix, attempts capture behavior...

Recently, direct position estimation (DPE) has arisen as a potential approach to deal with the positioning problem in global navigation satellite system receivers. The conventional solution is obtained two steps: synchronization parameters are estimated and then trilateration procedure charge of computing user's position, based on those parameters. In contrast, DPE estimates receiver's directly from digitized signal. was seen provide GNSS receivers appealing capabilities, such multipath...

Bayesian filtering is a statistical approach that naturally appears in many signal processing problems. Ranging from Kalman filter to particle filters, there plethora of alternatives depending on model assumptions. With the exception very few tractable cases, one has resort suboptimal methods due inability analytically compute recursion general dynamical systems. This why it attracted attention researchers order develop efficient algorithms implement it. We focus our interest into recently...

We describe an architecture for a multi-camera, multi-resolution surveillance system. The aim is to support set of distributed static and pan-tilt-zoom (PTZ) cameras visual tracking algorithms, together with central supervisor unit. Each camera (and possibly pan-tilt device) has dedicated process processor. Asynchronous interprocess communications archiving data are achieved in simple effective way via repository, implemented using SQL database. Visual from views stored dynamically into...

This paper shows the applicability of recently-developed Gaussian nonlinear filters to sensor data fusion for positioning purposes. After providing a brief review Bayesian filtering, we specially address square-root, derivative-free algorithms based on assumption and approximation rules numerical integration, namely Gauss--Hermite quadrature rule cubature rule. Then, propose motion model observations taken by an Inertial Measurement Unit, that takes into account its possibly biased behavior,...

Summary Low‐power devices are usually highly constrained in terms of CPU computing power, memory, and GPGPU resources for real‐time applications to run. In this paper, we describe RAPID, a complete framework suite computation offloading help low‐powered overcome these limitations. RAPID supports on Linux Android devices. Moreover, the implements lightweight secure data transmission operations. We present architecture framework, showing integration modules. show by extensive experiments that...

Ionospheric scintillation is one of the major threats and most challenging propagation scenarios affecting Global Navigation Satellite Systems (GNSS) related applications. The fact that this phenomenon causes severe degradations only in equatorial high latitude regions has led to very few contributions dealing with fundamental mitigation problem, being paramount importance safety critical applications advanced integrity receivers. goal paper twofold, first bring together relevant on GNSS...

Taking the work conducted by Global Navigation Satellite System (GNSS) Software Defined Radio (SDR) working group during last decade as a seed, this contribution summarizes for first time history of GNSS SDR development. It highlights selected implementations and achievements that are available to public or influenced general The relation standardization process Intermediate Frequency (IF) sample data metadata is discussed, recent update Institute (ION) standard recapitulated. focuses on...

This paper presents the design, proof-of-concept implementation, and preliminary performance assessment of an affordable real-time High-Sensitivity (HS) Global Navigation Satellite System (GNSS) receiver. Specifically tailored to capture track weak Galileo E1b/c signals, this receiver aims support research endeavors focused on advancing GNSS signal processing algorithms, particularly in scenarios characterized by pronounced attenuation. Leveraging System-on-Chip Field-Programmable Gate Array...

GNSS receivers compute its position by a two-steps procedure. First, synchronization parameters are estimated and, then, geometrical problem is solved to obtain receiver's position. This the approach typically taken due simplicity and modularity. However, recent results pointed out potential pitfalls of such approach. In that vein, Direct Position Estimation arise as alternative, computing directly from digitized signal. The latter performed single-step procedure, obtaining Maximum...

The performance of Global Navigation Satellite Systems (GNSS) is known to be severely affected in multipath scenarios, providing a biased position solution which could jeopardize possible geodetic-grade applications. Indeed, estimation and/or mitigation has attracted the attention many researchers recent years. Nevertheless, few been given detection multipath. That say, acknowledging that scenario corrupted by multiple propagation paths, and thus using adequate techniques combat its effect....

Carrier synchronization is of paramount importance in any communications or positioning system. Mass-market Global Navigation Satellite System (GNSS) receivers typically implement traditional carrier tracking techniques based on well-established phase-locked loop architectures, which are only reliable quite benign propagation conditions. Under nonnominal harsh conditions, the signal may be affected by shadowing, strong fading, multipath severe ionospheric scintillation, and thus,...

This letter deals with carrier synchronization in Global Navigation Satellite Systems. The main goals are to design robust methods and obtain accurate phase estimates under ionospheric scintillation conditions, being of paramount importance safety critical applications advanced receivers. Within this framework, the estimation versus mitigation paradigm is discussed together a new adaptive Kalman filter-based architecture that copes signals corrupted by scintillation. A key point model...

The use of a Direct Position Estimation approach has recently deserved some attention in the satellite-based navigation topic. In this paper, core idea is to merge motion model based on observations an Inertial Measurement Unit, accounting for possible biased measures, with signal parameterized by position receiver. Indeed, be estimated. Bayesian nonlinear filtering theory reviewed paper. Particularly, we focus our study particle and square-root derivative-free algorithms Gaussian assumption...

The prediction of the potential impact a wind farm on existing radiocommunication services before its installation allows planning alternative solutions to ensure coexistence energy and telecommunication facilities. Although some guidelines for safeguarding have been recently published, precise specific service can only be determined case-by-case basis, due multiple factors that must considered in analysis. This paper presents software tool accurate analysis degradation different systems....

Ionospheric scintillation is the name given to disturbance caused by electron density irregularities along propagation path of electromagnetic waves through ionosphere. These non-nominal conditions mainly cause carrier phase variations and amplitude fades. It important point out that both degradations are correlated, thus deep fades rapid (the so-called canonical fades) occur in a simultaneous random manner. Regarding synchronization problem under harsh conditions, such as high dynamics,...

This paper presents an open source implementation of a GNSS software receiver that targets Galileo E1B and E1C signals. After discussing the signal structure general architecture proposed receiver, we provide detailed descriptions main processing algorithms involved in acquisition tracking such navigation Experimental results with signals broadcast by in-orbit satellites validate approach. The connection to external (that allows in-the-loop testing implemented popular commercial tools) is...