GPS/Galileo Multipath Detection and Mitigation Using Closed-Form Solutions

We propose an efficient method for the detection of Line of Sight (LOS) and Multipath (MP) signals in global navigation satellite systems (GNSSs) which is based on the use of virtual MP mitigation (VMM) technique. By using the proposed method, the MP signals' delay and coefficient amplitudes can be efficiently estimated. According to the computer simulation results, it is obvious that our proposed method is a solution for obtaining high performance in the estimation and mitigation of MP signals and thus it results in a high accuracy in GNSS positioning

Unambiguous Multipath Mitigation Technique for BOC(n,n) and MBOC-Modulated GNSS Signals

We propose an efficient scheme for side peaks cancelation and multipath (MP) mitigation in binary offset carrier (n,n) (BOC(n,n)) and multiplexed BOC (MBOC) modulated signals. The proposed scheme reduces significantly the band of variation of MP errors in global navigation satellite system (GNSS). It consists of two versions. The first one is based on the use of maximum likelihood estimator (MLE) of MP signals and reference correlation functions (CFs) like that of pseudorandom noise (PRN) code without BOC subcarrier. In the second version, the former (MLE) is used with the reference BOC(n,n) or MBOC CFs. Unlike traditional BOC(n,n) and MBOC, that have CFs containing multiple peaks leading to potential tracking ambiguities, our proposed scheme does not contain any side peaks. In addition, all the MP signals with medium and long delays have no effect on the estimation of the pseudorange. On the other hand, all the methods proposed for mitigating MP in no-BOC scheme are practical for our scheme due to its CF which is similar to that of the PRN code. The computer simulation results show that the proposed scheme has superior performances in the reduction of the errors produced in the process of the delay estimation of line of sight (LOS) and caused by MP propagation. In fact, the performances of the proposed scheme are better with regard to that of the traditional BOC(n,n) and MBOC. Moreover, in the presence of noise, our proposed scheme keeps better performances than the common side peaks cancelation methods

General analytical models characterizing MBOC modulated signal

International audienc

Electrochemical Synthesis of an Organometallic Material Based on Polypyrrole/MnO2 as High-Performance Cathode

International audienceWe report herein the design ofpromising composite material as a cathode in a rechargeable battery by combining the properties of polypyrrole (PPy) and MnO2 particles.The compositeswerepreparedbyelectropolymerization of the pyrrole monomer followed by electrodeposition of a manganese salt suspension bytwo methods.The first method involved the formation of MnO2in situ in the PPy/ITO electrode, while the second method involved first a preliminary adsorption of Mn2+ions in the polymer, followed by anelectrochemical ofthe electrode. Themorphology of the resulting composite materials (PPy/MnO2) was studied by Energy-dispersive X-ray spectroscopy (EDS), X-ray diffractometry (XRD), scanning electron microscopy (SEM),Fourier-transform infrared (FTIR).The investigations of the electrochemical properties of the compositeelectrodes show thatthe presenceof MnO2play an important role in improving the surfaceof polymer films, which leads to lower charge transfer resistance and higher electrode activity.Forthe optimal synthesismethod, the electrode generates a maximum current of up to -7.9 mA.cm-2for the oxygen reduction reaction, which is eight times the current density delivered by the electrode without PPy