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The following topics are dealt with: GNSS challenges over the next 10 years; GPS; Galileo; multipath, interference & propagation; sensor fusion; space receivers; synergy between satellite navigation and communications; and signal processing.
The Orbit Determination and Time Synchronization (ODATIS) tool is a generic operational Precise Orbit Determination package developed by DEIMOS Space S.L.U. ODATIS was conceived and designed from the very beginning as the starting point for the implementation of any Flight Dynamics System, with emphasis on covering all phases of any type of Earth orbiter, in terms of mission operations.
The inception of C2 brought with it new issues to be considered, such as the merger of C2-capable and legacy receivers and the processing of data collected by a C2-capable receiver with satellite clock values generated using a legacy receiver network. Since receiver and satellite hardware delays for C2 measurements may not be necessarily the same of those for P2, a bias between P2 and C2 code measurements...
There is certainly a growing interest for the biggest countries in the world on having their own navigation system, which will result in many satellites and signals available in the near future. Given this fact, it starts making sense to design a multi-constellation GNSS receiver with an architecture that combines simplicity and flexibility. When building the front-end of the receiver, the well established...
There have already been a number of well documented cases where the GNSS signals have been interfered by different sources. A number of different methods has been developed to counteract this. One problem with doing experiments to validate the accuracy of interference detection system is that the GPS L1 band is protected, therefore it is difficult to get permission to deliberately broadcast on those...
The GRAS radio occultation instrument on board MetOp has continuously provided measurement data during almost four years. The measurement data are here used as a means to analyze the signal tracking performance of the GRAS instrument. The results demonstrate that the atmospheric Doppler shift is measured to an accuracy of 1.1 mm/s and that the on-board Doppler model is accurate within 4 m/s (or 20...
In this article the effect of decimation before acquisition stage in conventional Parallel Code Phase Search Acquisition (PCPSA) is discussed. In PCPSA, correlation function of the incoming signal and a locally generated Pseudo Random Noise (PRN) code is extracted by taking the Fast Fourier Transform (FFT) of the incoming signal and multiplying by conjugate FFT of a locally PRN code. Afterward, the...
There is an increasing concern that the open GNSS services are highly vulnerable to malicious and accidental denial of service events by low power jammers and location “spoofers” (meaconing). AJAMS (Anti Jamming and Meaconing System) is a new system concept, developed by Thales, built on the back of the services provided by Galileo, which requires no change to the existing Galileo signals or system...
GNSS is entering into a period of intense change over the next 5-10 years which will impact on users and operators of high-end GNSS equipment. For many years, GPS and GLONASS existed as the only systems. However, all is set to change with the advent of new global and regional systems (Galileo, Compass, IRNSS, GINS and QZSS), augmentation services and test satellites offering combined new and improved...
The evolution of Global Navigation Satellite Systems (GNSS) will see the introduction of new security services both in the civil and military domain. The threat of attacks against GNSS such as spoofing has lead to the design of GNSS signals and receiver technologies that attempt to address the problem both at the signal, data and receiver level. In particular, it is expected that modern GNSS will...
With Galileo, a satellite navigation system will be available that outperforms the current GPS and Glonass systems in terms of technical features, services and reliability. For testing and validation of Galileo-based applications two terrestrial test beds are currently being installed, where the future Galileo satellite navigation system can be used already now. The locations of these installations...
In this paper, an Orthogonal Frequency-Division Multiple Access (OFDMA) signal based on the IEEE 802.16 WiMAX standard with integrated navigation and communication capabilities is presented. The work has been carried out by DEIMOS Space under ESA contract for the Feasibility Study for a Reduced Planetary Navigation and Communication System (PLANCOM), which aims the definition of a local infrastructure...
This paper presents a new low cost GNSS Software (SW) receiver for Microsatellites. TES Electronic Solutions (Bruz, FRANCE) has been chosen by CNES for developing and manufacturing this equipment which should be tested on board the scientific microsatellites named TARANIS and MICROSCOPE that will be launched in 2013 and 2014. The GNSS receiver under development is a high-performance equipment specially...
INS/GNSS integration is a well known technique in navigation and, in general, in time-Position-Velocity-Attitude (tPVA) trajectory determination. It is also known, that INS and GNSS are complementary and that the key to their integration is the correct calibration of the Inertial Measurement Unit (IMU) sensors, of the IMU's Inertial Sensor Assembly (ISA) system parameters (axes misalignments and center...
Radio occultation technique performed with GNSS observables acquired by low Earth orbit satellites offer a great amount of data to carry out experiments and measurements in the framework of Earth survey. A dedicated GNSS-based radio occultation experiment has been designed to be installed onboard the microsatellite ALMASat-EO mission, developed at the Microsatellite Laboratory of the II Faculty of...
This publication explores the influence of a realistic multipath channel model to satellite navigation applications in urban environments. In this context we have discovered that there is a tradeoff between accuracy and robustness concerning the bandwidth. While narrow band signals such as GPS C/A, BOC (1,1) proved to be robust especially under shadowing situations the wideband signals lost lock very...
Current space missions demand to integrate as much functionality as possible. In this paper we present the results of an ongoing research on designing a single chip solution for a reconfigurable multi-band GPS/Galileo receiver front-end to provide flexibility in operation of a spacecraft while minimizing power, mass and cost. This receiver front-end is based on a direct conversion concept and uses...
Through the HybrId NAVigation system (HiNAV) project, Astrium Satellites studies the hybridisation of GNSS and Inertial Measurement Unit (IMU) measurements in a tight aiding / tight hybridisation architecture dedicated to the navigation function of launchers and re-entry spacecrafts. It is also a valuable solution for the safeguard function of launchers. In the frame of this project, the HiNAV product...
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