CiteULike: dcastro's galileo

Selection of the multiple-dwell hybrid-search strategy for the acquisition of Galileo signals in fading channels

ES Lohan — 2008-07-24T11:59:26-00:00

Personal, Indoor and Mobile Radio Communications, 2004. PIMRC 2004. 15th IEEE International Symposium on, Vol. 4 (2004), pp. 2352-2356 Vol.4.

The acquisition of CDMA signals in adverse mobile communication channels has been studied for more than five decades. However, the introduction of new standard proposals for the future European satellite system (i.e., Galileo) and for the modernized GPS has triggered new interest in fast and reliable acquisition strategies for CDMA systems with very high spreading factors (e.g., length of 10230 chips or higher). Typically, the double-dwell serial search strategies have been preferred for CDMA signal acquisition. Few papers have addressed also the problem of hybrid and parallel search strategies, but typically, the choice of the best number of dwells has not been discussed. The goal of this paper is to introduce a generic method for the computation of the mean acquisition time (MAT) for multiple-dwell hybrid-search acquisition blocks and to compare the performance of several multiple-dwell structures for CDMA systems with high spreading factors. It will be shown here that increasing the number of dwells does not always increase the performance from the point of view of the MAT. We also discuss the influence of various parameters on the selection of the multiple-dwell strategy and we present simulation results for a realistic Galileo signal.

Performance analysis of a stand-alone high-sensitivity receiver

Macgougan — 2008-07-24T11:47:54-00:00

GPS Solutions, Vol. 6, No. 3. (24 December 2002), pp. 179-195.

Abstract. The use of GPS for personal location using wireless devices requires satellite signal measurements both outdoors and indoors. In the outdoor environment propagation paths may range from line-of-sight to shaded or blocked. The indoor environment may range from single-floor wooden constructions to high-rise buildings and underground facilities. In this paper, a high-sensitivity receiver which operates in unaided stand-alone mode is tested under a range of shaded and blocked signal environments, ranging from residential outdoor areas to urban canyons and residential houses. The measurement analysis is performed in both the observation and position domains. The results show that the receiver tested is able to yield measurements with C/N0 degradations in excess of 20 dB-Hz, as compared to line-of-sight measurements. Position results are a function of the geometry of the remaining satellites, which in turn is a function of the environment.

Galileo RF Constellation Simulator Design Verification and Testing

P Boulton — 2008-07-17T15:34:29-00:00

Frequency Control Symposium, 2007 Joint with the 21st European Frequency and Time Forum. IEEE International (2007), pp. 511-516.

The characterisation and certification of Galileo Ground Receiver Chain (GRC) elements for the Galileo satellite-based navigation system is a critical programme activity, particularly for the In-Orbit Verification phase (IOV). Spirent has been contracted by the European Space Agency (ESA) via Thales Alenia Space to provide reference test equipment in the form of RF Constellation Simulators (RFCS) to support certification of the GRC and test user receiver elements. These RFCS are able to support all the Galileo frequencies and services, including open service, commercial service, safety-of-life service and public regulated service (PRS). This paper begins by presenting a brief technical description of the RCFS design and architecture and proceeds to describe the scope of and approach to the formal verification process. Where appropriate, further detail of some of the verification techniques used are presented including a statement of the requirement, the test equipment and procedures involved and a summary of the results obtained. Most specific PRS aspects are excluded from this paper due to their classified status. Initial conclusions are drawn and future work is described.

Loser: Geopositioning - No Payoff For Galileo Navigation System

W Sweet — 2008-06-22T14:52:37-00:00

Spectrum, IEEE, Vol. 45, No. 1. (2008), pp. 48-49.

The idea of a European geopositioning system similar to the U.S. Global Positioning System originated a decade ago. Today the system is five years behind schedule and, in terms of public funding, at least a couple of billion euros over budget.

GIOVE-A SIS Experimentation and Receiver Validation: Laboratory Activities at ESTEC

Massimiliano Spelat — 2008-06-13T06:47:47-00:00

Satellite Communications and Navigation Systems (2008), pp. 241-257.

The European Space Agency (ESA) and the Surrey Satellite Technology LTD (SSTL) have completed the on-orbit preparation and activated the payload of GIOVE-A, the first Galileo satellite launched last December, the 28th. After successful launch and platform commissioning achievement, GIOVE-A started signals transmission on 12 January 2006. For the time being the quality of the signal broadcast by GIOVE-A is under examination by mean of sophisticated equipments and facilities, including the ESA ground station in Redu (Belgium) and the Rutherford Appleton Laboratory (RAL) Chilbolton Observatory in the United Kingdom. It is clear that the European Galileo satellite navigation system is moving into a crucial phase concerning the development process; therefore the possibility of testing and validating hardware/software tools (e.g. user receivers) will play a key role from the manufacturers point of view. In this context the navigation laboratory at ESA's European Space Research and Technology Centre (ESTEC), in the Netherlands, could be considered relevant in the receivers validation procedures, as well as in the Signal-In-Space (SIS) experimentation activity, where the GSTB-v2 Experimental Test Receiver (GETR) plays a key role. The paper will provide the overview of the set-up available in the navigation laboratory at ESTEC, describing the equipments composing the test bench. The Galileo Signal Validation Facility (GSVF-v2) will be presented pointing out the capabilities in the Galileo-like signal generation. In particular, the Galileo L1 Open Service (OS) signal will be analyzed, and the corresponding GETR tracking performance will be presented in terms of code tracking noise curves, autocorrelation function and multipath envelope. Tracking performance for the Galileo L1 OS signal in multipath environments will be evaluated in terms of static and dynamic contributions. Finally, some screenshots of the GETR graphical user interface (while tracking GIOVE-A signals) will also be included in the paper, as the prove that the entire set-up has been fully integrated with the Space Engineering's Galileo antenna for the reception and process of live GIOVE-A signals.

Design and Validation of Digital Channels for a Galileo Receiver Prototype

F Rossi — 2008-05-18T14:17:34-00:00

Digital System Design: Architectures, Methods and Tools, 2006. DSD 2006. 9th EUROMICRO Conference on (2006), pp. 545-549.

This paper describes the design activity for the digital baseband processing of a prototype receiver for the Galileo system. According to the applied hardware-software partitioning, the high rate elaborations have been implemented on a dedicated hardware, a Xilinx Virtex2 FPGA, while the remaining low rate processing has been programmed on an analog device DSP. A customarily designed prototype board has been used to validate the receiver under real working conditions: a dynamic GPS and Galileo scenario. Particularly, the paper focuses on the receiver digital channel, which is the critical core of the FPGA, from VHDL modeling to hardware implementation and testing

A Theoretical Survey of the Spreading Modulation of the New GPS Signals (L1C, L2C, and L5)

IF Progri — 2008-05-18T12:33:34-00:00

ION NTM 2007 Proceedings (2007)

Simulation & verification of new architectures for Galileo Navigation Signal Demodulation

S Fischer — 2008-05-18T12:17:05-00:00

ION GNSS 2003 (2003)

Galileo receivers - challenges and performance

M Hollreiser — 2008-05-13T10:06:32-00:00

Microwave Conference, 2004. 34th European, Vol. 1 (2004), pp. 321-324.

Design and practical implementation of multifrequency RF front ends using direct RF sampling

ML Psiaki — 2008-05-07T06:08:30-00:00

Microwave Theory and Techniques, IEEE Transactions on, Vol. 53, No. 10. (2005), pp. 3082-3089.

The use of direct RF sampling has been explored as a means of designing multifrequency RF front ends. Such front ends will be useful to multifrequency RF applications such as global navigation satellite system receivers that use global positioning system (GPS) L1, L2, and L5 signals and Galileo signals. The design of a practical multifrequency direct RF sampling front end is dependent on having an analog-to-digital converter whose input bandwidth accommodates the highest carrier frequency and whose maximum sampling frequency is more than twice the cumulative bandwidth about the multiple carrier signals. The principle of direct RF sampling is used to alias all frequency bands of interest onto portions of the Nyquist bandwidth that do not overlap. This paper presents a new algorithm that finds the minimum sampling frequency that avoids overlap. This design approach requires a multifrequency bandpass filter for the frequency bands of interest. A prototype front end has been designed, built, and tested. It receives a GPS coarse/acquisition code at the L1 frequency and GPS antispoofing precision code at both L1 and L2. Dual-frequency signals with received carrier-to-noise ratios in excess of 52 dB-Hz have been acquired and tracked using this system.

Enhanced decoding for the Galileo low-gain antenna mission

S Dolinar — 2008-04-15T18:05:18-00:00

Information Theory, 1994. Proceedings., 1994 IEEE International Symposium on (1994), 344.

Due to a malfunctioning high-gain antenna, the Galileo spacecraft is transmitting all its data through a low-gain antenna, and the data rate will seldom exceed 100 bits per second during its two-year tour of Jupiter's satellites. To offset some of the performance loss, the spacecraft's computer will be extensively reprogrammed to include new data compression and coding algorithms. The baseline coding system for the low gain antenna mission uses a Reed-Solomon (RS) outercode of block length 255 concatenated with a (14, 1/4) convolutional inner code, and interleaves the RS symbols to depth eight. The convolutionally encoded symbols are decoded by a maximum likelihood (Viterbi) decoder, and each RS codeword is decoded algebraically. Two types of decoding enhancements were proposed as feasible due to the low data rate. The first type of redecoding is confined to the RS decoder and utilizes information from neighboring codewords within the same interleaved block to erase unreliable symbols in undecoded words. The second type involves redecoding by the Viterbi decoder, using information fed back from codewords successfully decoded by the RS decoder

Comparison of the sensitivity limits for GPS and Galileo receivers in multipath scenarios

A Schmid — 2008-04-15T18:03:01-00:00

Position Location and Navigation Symposium, 2004. PLANS 2004 (2004), pp. 503-509.

The global navigation satellite systems (GNSS) market is anticipated by most market researchers to experience exponential growth in the consumer segment, to the largest extend through the introduction of location based services (LBS). LBS - including the U.S. E-911 mandate - require position fixes at demanding rural sites, such as urban canyon, moderate indoor, and in vehicles without external antennae. The satellite signals are not only attenuated, but also subjected to strong multipath fading. Developing GPS/Galileo receivers for high-volume markets requires support for LBS, which in turn necessitates enhanced receiver sensitivity and multipath robustness. Which business cases are feasible is therefore partially determined by the maximally achievable sensitivity under various multipath scenarios. These sensitivity limits form a baseline for the receiver design. This paper algebraically derives the sensitivity limits for acquisition (i.e. synchronization) of direct sequence spread spectrum positioning signals under multipath propagation conditions. The derived formulas are then evaluated exemplarily for the parameters of the openly accessible L1-band GPS and Galileo signals, while they are also valid for other positioning signals. As commonly applied in wireless communications, the multipath environment is modelled with stochastic Ricean fading processes. The derived sensitivity limits are based on the stochastic models for multipath and noise, being transformed by RF-downconversion, despreading, coherent integration, envelope detection, noncoherent integration, and Neyman-Pearson detection. These results are also provided as plots of probability of detection versus carrier power to noise power spectral density, parameterized for various noncoherent integration times and Ricean factors.

Feedforward delay estimators in adverse multipath propagation for Galileo and modernized GPS signals

Elena Lohan — 2008-02-22T07:32:24-00:00

EURASIP J. Appl. Signal Process., Vol. 2006, No. 1. (January uary), pp. 157-157.

Girasole Receiver Development for Safety of Life Applications

Livio Marradi — 2008-02-14T18:11:57-00:00

Satellite Communications and Navigation Systems (2008), pp. 313-327.

The GIRASOLE Safety of Life Receiver is developed in the frame of the Galileo Joint Undertaking (GJU) Research and Development activities, in the context of the European Commission 6th Framework Programme 2nd call by ALCATEL ALENIA SPACE Italia (AASI), manufacturer leader of advanced, high performance GPS/EGNOS/Galileo receivers for space and safety-critical applications. Differently from GPS, which relies on an external signal (EGNOS), one of the most appealing features of Galileo is the signal embedded integrity. As this characteristic provides the users with information about the availability and correctness of the Galileo system and signal, Galileo is particularly attractive for all the critical applications that undergo the general name of Safety of Life, or SoL for brevity. The Safety of Life Services (SoL) are targeted at users who need assurance of service performance in real-time. Typically they are safety critical users, for example Aviation, Maritime and Rail, whose applications or operations require stringent performance levels. Other applications can be envisaged like emergency and road. In these types of applications, the receiver plays an important role since is one of the key elements of the safety chain. The main characteristic of such type of receivers is their capability to detect failures that can come from different sources like the Signal In Space, the environment (ionosphere, troposphere, interference and multipath effects), the constellation etc. and be capable to interpret the integrity information broadcast by the satellites. In the frame of its 2nd Call, the Galileo Joint Undertaking (GJU) has launched several activities aiming to provide basic technological elements (i.e. receivers) useful for the different services offered by Galileo. Within this frame, GJU has selected the GIRASOLE project as the one aiming at development of receivers for SoL application. In the framework of the project, Alcatel-Alenia-Space Italia S.p.A. (AAS-I) is leading a Consortium of several companies from eight different countries all over the world. The GIRASOLE project aims to allow strategic developments of technologies and basic elements of a Safety of life (SoL) Galileo Receiver. The GIRASOLE system architecture is based on GARDA heritage, a project developed by AASI-Milano under GJU contract (1st call) with the key objective to build an advanced user receiver prototype, configurable to simultaneously track Galileo/GPS/SBAS satellites, supporting all Galileo frequencies and modulations. The possibility to have Galileo receivers prototypes available at an early stage will provide benefits for standardization and certification of the receivers within each user communities, while facilitating the market penetration of Galileo. The receiver processes Galileo signals on the L1, E5b bands and GPS/EGNOS signals on the L1 band. It also provides combined Galileo + GPS Navigation solution, Integrity calculations (HMI, critical satellite prediction and Navigation warning) using Galileo and EGNOS Integrity message, interference and multipath mitigation, support to the use of Local Elements and output raw measurements data of each satellite.

The Concept of the GALILEO Receiver

Adam Lipka — 2008-02-14T16:24:55-00:00

EUROCON, 2007. The International Conference on "Computer as a Tool" (2007), pp. 1106-1112.

The developing of the global European satellite navigation system GALILEO proves to be one of the most significant challenges these days. The following paper provides a brief description of a system itself but first of all it discusses the concept of a GALILEO receiver which takes advantage of the SDR (Software Defined Radio) technology. Both necessary algorithm as well as the concept of a hardware realization are presented. In the final part a conclusion is presented.

Receiver architecture synergies between future GPS/Galileo and UMTS/IMT-2000

G Heinrichs — 2008-02-11T09:41:27-00:00

Vehicular Technology Conference, 2002. Proceedings. VTC 2002-Fall. 2002 IEEE 56th, Vol. 3 (2002), pp. 1602-1606 vol.3.

The location requirements for emergency callers outside urban areas can hardly be fulfilled without Global Navigation Satellite Systems (GNSS). Consequently, interest in positioning techniques based on use of a GNSS such as GPS or on the cellular network infrastructure itself is growing rapidly in the mobile telephone community. The technical similarity based on the use of DS-CDMA spread-spectrum technology opens the door for the combination of GNSS with cellular network-based wireless location and positioning. The paper seeks to provide some initial answers to the question of whether mobile handset architecture synergies exist for the combination of GNSS with UMTS/cdma2000 cellular wireless networks. In this respect, we pay particular attention to the RAKE receiver architecture employed in mobile CDMA cellular handsets.

MBOC: The New Optimized Spreading Modulation Recommended for GALILEO L1 OS and GPS L1C

GW Hein — 2008-02-08T23:57:44-00:00

Position, Location, And Navigation Symposium, 2006 IEEE/ION (2006), pp. 883-892.

Synthesis of a Galileo and Wi-Max Three-Band Fractal-Eroded Patch Antenna

R Azaro — 2007-12-31T18:19:52-00:00

Antennas and Wireless Propagation Letters, IEEE, Vol. 6 (2007), pp. 510-514.

<para> In this letter, the synthesis of a three-band patch antenna working in $E_5$-$L_1$ Galileo and Wi-Max frequency bands is described. The geometry of the antenna is defined by performing a Koch-like erosion in a classical rectangular patch structure according to a Particle Swarm strategy to optimize the values of the electrical parameters within given specifications. In order to assess the effectiveness of the antenna design, some results from the numerical synthesis procedure are described and a comparison between simulations and experimental measurements is reported. </para>

Quad-band patch antenna for Galileo and Wi-Max services

E Zeni — 2007-12-31T18:18:03-00:00

Electronics Letters, Vol. 43, No. 18. (2007), pp. 960-962.

GALILEO system overview

Trautenberg — 2007-11-22T15:26:33-00:00

Acta Astronautica, Vol. 55, No. 3-9. ( 2004), pp. 643-647.

This paper presents a brief description of the GALILEO services and summarizes the main performance parameters. The current status of the system architecture definition is presented in a concise overall view on the various elements of the system and their functions with a main focus on the GALILEO ground segment.

On the Acquisition Ambiguity for Galileo BOC(n,n) Modulated Signals

G Avellone — 2007-11-14T19:20:29-00:00

Communications, 2007. ICC '07. IEEE International Conference on (2007), pp. 4438-4443.

GRANADA validation of optimized Multiple Gate Delay structures for Galileo SinBOC(1,1) signal tracking

Xuan Hu — 2007-11-14T19:19:57-00:00

Telecommunications, 2007. ITST '07. 7th International Conference on ITS (2007), pp. 1-5.

Multipath is an issue of paramount importance in the GNSS context, and the dominant error source for the Delay Lock Loop (DLL) used for code tracking. This paper introduces an optimized Multiple Gate Delay (MGD) code tracking implementation in the modified GRANADA Bit-true Software Receiver Simulator. Then the tracking performance of the optimized MGD structure is presented via GRANADA simulation results. This tracking performance is also compared with the tracking performance of High Resolution Correlator (HRC) and of the narrow correlator or narrow Early-Minus-Late (nEML) structures. The tracking performance criteria include Multipath Error Envelopes (MEEs) and Root Mean Square Error (RMSE) for both multipath static channels and fading channels. It is shown that the optimized MGD structure has a better performance than nEML and HRC in the multipath channels, and that the GRANADA Bit-true Software Receiver Simulator is a useful tool for testing the performance.

Employment of a multipath receiver structure in a combined GALILEO/UMTS receiver

R Bischoff — 2007-11-12T14:12:04-00:00

Vehicular Technology Conference, 2002. VTC Spring 2002. IEEE 55th, Vol. 4 (2002), pp. 1844-1848 vol.4.

Current navigation systems like GPS (Global Positioning System) and its Russian counterpart GLONASS (Global Navigation Satellite System) only evaluate the direct signal path. The receivers treat the reflected paths also reaching the receiver antenna as disturbance which has to be suppressed. Multipath affects the tracking accuracy by resulting in a degeneration of the S-curve of the DLL (delay locked loop). Nowadays the future European systems GALILEO and GPSIIF/III with two new signals are on the way to the market and it is time to think about new receiver structures. Therefore we investigated if it is possible to use multipath for navigation constructively.

CN/sub 0/ estimation and near-far mitigation for GNSS indoor receivers

G Lopez-Risueno — 2007-10-25T08:55:32-00:00

Vehicular Technology Conference, 2005. VTC 2005-Spring. 2005 IEEE 61st, Vol. 4 (2005), pp. 2624-2628 Vol. 4.

This paper covers two key points in indoor and dense-urban positioning using Global Navigation Satellite Systems: CN/sub 0/ estimation, and near-far estimation problem. For the former, a novel CN/sub 0/ estimator adequate to deal with the low signal levels encountered in indoor and dense-urban environments is described. For the latter, the results of a novel near-far problem mitigation technique are presented. Both simulations and live data have been used to illustrate the advantages of the proposed algorithms.

Galileo civil signal modulations

Emilie Rebeyrol — 2007-10-23T09:30:08-00:00

GPS Solutions, Vol. 11, No. 3. (31 July 2007), pp. 159-171.

Abstract Spectrum limitations for navigation systems require that the various navigation signals broadcast by the Galileo system must be combined and must utilize bandwidth-efficient modulations. At the L1 band, one of the most important questions is how to combine all the Open Service signals and the Public Regulated Service signal at the payload level, while maintaining good performance at reception. The Interplex modulation, a particular phase-shifted-keyed/phase modulation (PSK/PM), was chosen to transmit these signals because it is a constant-envelope modulation, thereby allowing the use of saturated power amplifiers with limited signal distortion. The Interplex modulation was also taken as baseline at the E6 band to transmit the three channels and the services associated on the same carrier frequency. At the E5 band, the modulation must combine two different services on a same constant envelope composite signal, while keeping the simplicity of a BOC implementation. The constant envelope Alternate Binary Offset Carrier (ALTBOC) modulation was chosen as the solution to transmit the Galileo E5 band signal. The main objective of this paper is to study these Galileo modulations. After the introduction, the E5 band signals are described, followed by the Alternate BOC modulation which has been chosen to transmit them. The second part describes the general formulation of the Interplex modulation and its key parameters for an optimal multiplexing of the Galileo L1 band signals. Since the Galileo Open Service signals at the L1 band are still not yet completely specified, different test cases are considered and their impact on the resulting choice for the Interplex modulation parameters is exposed.