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Bandpass Continuous-Time Delta-Sigma Modulator forWireless Receiver IC
Huey Jen Lim,Simon Sheung Yan Ng,Minkyu Je
International Journal of Information and Electronics Engineering , 2013, DOI: 10.7763/ijiee.2013.v3.252
Abstract: Bandpass ADC is well known to be adopted in thenarrowband receiver design in order to reduce the systemcomplexity, increase integration and improve performance bydigitizing the bandpass signal directly without prior conversionto baseband. A fully differential feedforward fourth-ordercontinuous-time bandpass delta-sigma modulator is presented.The proposed single-bit modulator can receive 172.8kHz IFsignals by using an oversampling clock frequency of 5.53MHzwith an OSR of 128. Simulated result showing that dynamicrange of 78dB within bandwidth of 21.6kHz is achieved and thecurrent consumption is around 1.2mA at 1.5V power supply.The design had been implemented in 0.13μm 1P6M CMOSprocess with MIM capacitors.
The Utilization of Novel Bandpass Sigma-delta Modulator for Capacitance Pressure Sensor Signal Processing
J. Haze,L. Fujcik,R. Vrba,M. Pavlik
Radioengineering , 2008,
Abstract: The paper deals with a novel approach to processing of pressure sensor signals. A bandpass sigma-delta modulator is used for this purpose. This technique is relatively new and it is not used widely, because this kind of modulator is usually utilized for wireless and video applications. Since the bandpass sigma-delta modulator works within its defined band it is resistant to offsets of its sub-circuits. The main stages of this modulator are implemented by means of switched-capacitor (SC) technique. The article presents the basic ideas of this approach and simulation results of the first order of ideal and real modulator. The paper also shows the design of the phase locked loop (PLL) block for synchronization of sensor signal and modulator driving signal. The simple evaluation board was fabricated for confirmation of the proposed principle. Also shown are the results of the chip testing, the modulator layout and the design and test results of the second order of bandpass sigma-delta modulator briefly.
SDR Joint GPS/Galileo Receiver from Theory to Practice
International Journal of Aerospace Sciences , 2012, DOI: 10.5923/j.aerospace.20120101.01
Abstract: This paper deals with a Software Defined Radio (SDR) receiver capable to process GPS and Galileo signals jointly. A large set of possible solution can be implemented, with the main aim of assessing the performance of the receiver for the considered architectures. For this reason, software receivers, either real-time or non-real-time, are fundamental tools to enable research and new developments in the field of GNSSs. In this paper our intent is to discuss some of the choices one can face when implementing an SDR GNSS receiver, switching from the theory to the practice. We focus our attention on the pseudorange construction and the Position, Velocity and Time (PVT) estimation stage, discussing different algorithms to implement these blocks. Our aim is to offer an insight on the options to implement those stages of the receiving chain, in a practical vision which is difficult to find in the available literature.
Economic Galileo E5 Receiver
P. Kovar,P. Kacmarik,F. Vejrazka
Radioengineering , 2012,
Abstract: The Galileo system introduces an extremely wideband civil E5 signal for high precision navigation. The structure of the receiver for the E5 signal is complicated due to the signal complexity and the large bandwidth. It is possible to process the whole E5 signal or process separately E5a and E5b parts combining obtained results afterwards (we call here such method as piece-wise processing). The second procedure has three times worse standard deviation of the pseudorange then first one. The main goal of the paper is to present a design of an E5 receiver which we will call the economic E5 receiver (ecoE5). It is built from jointly controlled correlators for the processing of the E5a and E5b signals which are parts of the E5 signal. Control of these partial E5a and E5b correlators is realized by only one delay and one phase lock loops. The performance, i.e. the pseudorange noise and multipath errors, of the receiver equipped with the ecoE5, is only slightly worse (the standard deviation of the pseudorange noise is 10 - 20% larger) than the performance of the optimal E5 receiver and it is much better than the performance of the receiver combining the piecewise (E5a and E5b) measurements. The ecoE5 receiver hardware demands are about one quarter of the hardware demands of the classical E5 receiver.
An Improved Model for Single-Frequency GPS/GALILEO Precise Point Positioning  [PDF]
Akram Afifi, Ahmed El-Rabbany
Positioning (POS) , 2015, DOI: 10.4236/pos.2015.62002
Abstract: This paper introduces a new precise point positioning (PPP) model, which combines single-fre- quency GPS/Galileo observations in between-satellite single-difference (BSSD) mode. In the absence of multipath, all receiver-related errors and biases are cancelled out when forming BSSD for a specific constellation. This leaves the satellite originating errors and atmospheric delays un- modelled. Combining GPS and Galileo observables introduces additional biases that have to be modelled, including the GPS to Galileo time offset (GGTO) and the inter-system bias. This paper models all PPP errors rigorously to improve the single-frequency GPS/Galileo PPP solution. GPSPace PPP software of Natural Resources Canada (NRCan) is modified to enable a GPS/Galileo PPP solution and to handle the newly introduced biases. A total of 12 data sets representing the GPS/Galileo measurements of six IGS-MEGX stations are processed to verify the newly developed PPP model. Precise satellite orbit and clock corrections from IGS-MEGX networks are used for both GPS and Galileo measurements. It is shown that sub-decimeter level accuracy is possible with single-frequency GPS/Galileo PPP. In addition, the PPP solution convergence time is improved from approximately 100 minutes for the un-differenced single-frequency GPS/Galileo solution to approximately 65 minutes for the BSSD counterpart when a single reference satellite is used. Moreover, an improvement in the PPP solution convergence time of 35% and 15% is obtained when one and two reference satellites are used, respectively.
Effect of Narrowband Interference on Galileo E1 Signal Receiver Performance  [PDF]
Jie Zhang,Elena-Simona Lohan
International Journal of Navigation and Observation , 2011, DOI: 10.1155/2011/959871
Abstract: Satellite navigation technology is becoming essential for civil application. The high-accuracy navigation service is demanded. However, the satellite signal may be exposed to the signal from other systems, which are sharing the same frequency band. This is a potential threat for the performance of navigation devices. The aim of this paper is to present an interference impact assessment in the context of global navigation based on the new modulation Composite Binary Offset Carrier (CBOC) that will be used for Galileo E1 civil signal. The focus is on the analysis of the Galileo CBOC-modulated signal robustness against narrowband interference. 1. Introduction Satellite navigation is a process of providing autonomous global geospatial position with coverage all over the world. The navigation technology is essential for several civil applications, such as in the transportation field (e.g., road, rail, and aviation). Other applications, such as precision agriculture, wildlife behavior monitoring, surveying, and time-based applications are also based on the estimation of users’ Position, Velocity, and Time (PVT) [1]. These applications, especially the ones dealing with safety, require high accuracy of users’ PVT estimation. The Global Navigation Satellite Systems (GNSSs) signals are allocated to Radio Navigation Satellite Services (RNSSs) and Aeronautical Radio Navigation Services (ARNSs) on a worldwide coprimary basis. However, the Global Navigation Satellite Systems (GNSSs) signals may be exposed to potential interference from other services that are sharing the similar frequency band. They could likely represent potential threats for GNSS devices. The interference may degrade the GNSS receivers’ performance and compromise the safety. Potential interferences are largely emanated from unintentional source or intentional jamming and spoofing of GNSS signal. Radio frequency interference (RFI) is one of the unintentional interference sources, whose frequency might be located in the satellite signal bands. RFI is normally classified as either wideband or narrowband, depending on whether its bandwidth is large or small relative to the bandwidth of the desired GNSS signal. Wideband interference can be a Gaussian waveform as in the case of Ultra-Wideband (UWB) systems or harmonic from television transmission overcoming the front-end filter of a GNSS receiver [2]. Narrowband interference could originate from Amplitude Modulation (AM) or Frequency Modulation (FM) station. The interference represents an impairing factor in GNSS application mainly due to the low power
В.П. Харченко,О.Г. Кукуш,?.А. Знаковська
Proceedings of National Aviation University , 2012,
Abstract: In this article the upgraded mathematical model for identification of constellation of navigating satellites GPS, GLONASS and GALILEO is presented. This model may be used for more adequate aeronavigation means integrity definition. Рассмотрена модернизированная математическая модель для идентификации созвездия навигационных спутников GPS, GLONASS, GALILEO. Показано, что модель может быть использована для более адекватного определения целостности аэронавигационных средств. Розглянуто модерн зовану математичну модель для дентиф кац суз р’я нав гац йних супутник в GPS, GLONASS, GALILEO. Показано, що модель може бути застосована для б льш адекватного визначення ц л сност аеронав гац йних засоб в.
Behavioral Modeling and Simulation of Cascade Multibit ΣΔ Modulator for Multistandard Radio Receiver  [PDF]
Sonia Zouari, Houda Daoud, Mourad Loulou, Patrick Loumeau, Nouri Masmoudi
Circuits and Systems (CS) , 2013, DOI: 10.4236/cs.2013.41011

In this paper, a cascade Sigma-Delta (ΣΔ) Analog to Digital Converter (ADC) for multistandard radio receiver was presented. This converter is supposed to be able to support GSM, UMTS, Wifi and WiMAX communication standards. The Sigma-Delta modulator makes use of 4 bit quantizer and Data-Weighted-Averaging (DWA) technique to attain high linearity over a wide bandwidth. A top-down design methodology was adopted to provide a reliable tool for the design of reconfigurable high-speed ΣΔMs. VHDL-AMS language was used to model the analog and mixed parts of the selected 2-1-1 cascade ΣΔ converter and to verify their reconfiguration parameters based on behavioural simulation. This multistandard architecture was high level sized to adapt the modulator performance to the different standards requirements. The effects of circuit non-idealities on the modulator performance were modeled and analyzed in VHDLAMS to extract the required circuit parameters.

Comparison of multipath mitigation based on Galileo receiver

ZHANG Li-fen,TIAN Zeng-shan,

计算机应用研究 , 2009,
Abstract: In order to minimize the influence of multipath signal, several approaches can be taken into account. Among them are the use of special multipath limiting antennas,multi-antenna spatial processing or carrier smoothing to reduce code multipath. However, the most important mitigation approaches are receiver-internal correlation techniques.This paper provided a survey of current receiver-internal correlation techniques which were narrow correlator technique and high resolution correlator code tracking technique.From the simulation results,the receiver-internal correlation techniques are able to minimize multipath,and the high resolution correlator code tracking technique is better than the narrow correlator technique in the multipath mitigation.
Improved Between-Satellite Single-Difference Precise Point Positioning Model Using Triple GNSS Constellations: GPS, Galileo, and BeiDou  [PDF]
Akram Afifi, Ahmed El-Rabbany
Positioning (POS) , 2016, DOI: 10.4236/pos.2016.72006
Abstract: This paper introduces a new dual-frequency precise point positioning (PPP) model, which combines the observations of three different GNSS constellations, namely GPS, Galileo, and BeiDou. Our model is based on between-satellite single-difference (BSSD) linear combination, which cancels out some receiver-related biases, including receiver clock error and non-zero initial phase bias of the receiver oscillator. The reference satellite can be selected from any satellite system GPS, Galileo, and BeiDou when forming BSSD linear combinations. Natural Resources Canada’s GPS Pace PPP software is modified to enable a combined GPS, Galileo, and BeiDou PPP solution and to handle the newly introduced biases. A total of four data sets at four IGS stations are processed to verify the developed PPP model. Precise satellite orbit and clock products from the IGS-MGEX network are used to correct both of the GPS and Galileo measurements. It is shown that using the BSSD linear combinations improves the precision of the estimated parameters by about 25% compared with the GPS-only PPP solution. Additionally, the solution convergence time is reduced to 10 minutes for both BSSD scenarios, which represent about 50% improvement in comparison with the GPS-only PPP solution.
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