GNSS signal acquisition in the presence of sign transitions

The next generation of Global Navigation Satellite Systems (GNSS), such as Galileo [1] and GPS modernization [2], will use signals with equal code and bit periods, which will introduce a potential sign transition in each segment of the signal processed in the acquisition block. If FFT is used to perform the correlations a sign transition occurring within the integration time may cause a splitting of the main peak of the Cross Ambiguity Function (CAF) into two smaller lobes along the Doppler shift axis [3]. In this paper a method to overcome the possible impairments due to the lobe splitting is proposed and validated by simulatio

Optimal Planning and Operation Scheduling of Battery Storage Units in Distribution Systems

In the last years, the electricity system has been subject to a paradigm change, due to increasing share of installed renewable energy sources-based power plants. This fact is leading electrical system - which proper operation was however affected by the intermittent nature of renewables - to become more “green”. The union of energy chain de-carbonization with service reliability opens new opportunities for storage systems, although their relatively high cost highlighted the importance of optimal decisions in sizing, placing and operation of such systems. For addressing these aspects, appropriate mathematical models and optimization methods are needed: in this paper, a novel and efficient hybrid optimization algorithm is introduced, to solve i) sizing, ii) placement and iii) operation of arbitrary storage systems. This method is then applied to a low voltage grid, to demonstrate the effectiveness of the proposed methodology

Comparison between Galileo CBOC Candidates and BOC(1,1) in Terms of Detection Performance

Many scientific activities within the navigation field have been focused on the analysis of innovative modulations for both GPS L1C and Galileo E1 OS, after the 2004 agreement between United States and European Commission on the development of GPS and Galileo. The joint effort by scientists of both parties has been focused on the multiplexed binary offset carrier (MBOC) which is defined on the basis of its spectrum, and in this sense different time waveforms can be selected as possible modulation candidates. The goal of this paper is to present the detection performance of the composite BOC implementation of an MBOC signal in terms of detection and false alarm probabilities. A comparison among the CBOC and BOC(1,1) modulations is also presented to show how the CBOC solution, designed to have excellent tracking performance and multipath rejection capabilities, does not limit the acquisition process

Comparative Analysis of Acquisitions Techniques for BOC Modulated Signals

This work will address the analysis of acquisition schemes and algorithms useful for acquiring the Galileo BOC modulated signals and its performance. A modified acquisition strategy based on the Bump Jumping algorithm will be addressed. The impact of the side lobes (in terms of detection probability and false alarm probability) in different system conditions is evaluated. In order to compare the various acquisition systems and to identify the schemes that can be successfully used in the acquisition of Galileo signals, a simulation based analysis has been performed to identify the best strategy (and the relative parameters) that can work with the Galileo signal trading the receiver complexity with the expected performanc

Acquisition Performance Analysis for BOC Modulated Signals

The advent of the new European satellite navigation system Galileo and the current study of a new generation of GPS satellites are increasing the interest towards navigation related systems, services and applications. Both the systems foresee improved performances with respect to the present GPS C/A code, mainly achieved by using novel modulation schemes for the signals-In-Space. The Binary Offset Carrier (BOC) modulation, different (and longer) codes, and pilot channels have been proposed as a mean to reduce the mutual interference on common carriers, and also as a way to improve the expected performance. On the receiver side these system design choices have a relevant impact on the receiver architecture which as now to deal with different signals. One of the core techniques affected by these choices is certainly the acquisition stage, which has the goal to detect the presence of a certain satellite and to provide a rough estimation of the local code alignment and Doppler shift. This work will address the comparison of the acquisition schemes useful for acquiring the Galileo BOC modulated signals It is well known that several 1

Quality Monitoring for Multipath Affected GPS Signals

Abstract. The ability to monitor and detect any disturbances on the PRN code signals transmitted from the navigation satellite constellation is of primary importance. It is known that the tracking performance of a navigation receiver stems from the correlation property of the PRN code signals transmitted. These anomalies can be detected in several different ways, either observing the outputs of navigation user receivers, or processing the received signal within the receiver. Quality control is the process that defines how well the solution of a problem is known and in the context of navigation, it consists of assuring an agreed level of accuracy, reliability and robustness for the measurements. In this work a modified version of the conventional tracking scheme will be proposed with the aim of monitoring the quality of th

Acquisition and tracking of Galileo IOV E5 signals: experimental results and performance evaluation

An assessment of the Galileo In-Orbit Validation (IOV) signals on the E5 band is presented in this paper, investigating the signal features compared with the expected characteristics as described in the Galileo Interface Control Document (ICD) specifications. In detail, the results in terms of signal acquisition and tracking during multiple satellite passes are discussed, providing also a description of the experimental setup used in order to separately receive and process E5a and E5b signals. The analysis covers the received signal strength versus the satellite elevation, the modulation format, and the presence of navigation data and secondary code chips. Since at time of writing both the two Galileo IOV satellites (PFM and FM2) are broadcasting E5 signals, the results obtained processing their E5a and E5b signals are discussed. In addition, these signals are also compared with those currently transmitted by the two experimental Galileo satellites, GIOVE-A and GIOVE-

Efficient Signal Acquisition and Tracking for a Real Time GPS/Galileo Software Receiver

In a Global Navigation Satellite System (GNSS) receiver the acquisition algorithms as well as the signal tracking play an important role in the receiver functioning. When the receiver is implemented in software radio technology the demanding computational complexity becomes a critical issue as much as the algorithms performance and stability. This paper presents the solutions adopted for the signal acquisition and tracking for the N-Gene fully software receiver. The acquisition algorithm is a variant of the classical "fast acquisition algorithm" where the signal correlation is obtained in time domain by means of two Fast Fourier Transforms (FFTs) and a single Inverse Fast Fourier Transform (IFFT). A solution for improving the tracking performance in case of low C/N0, is also proposed. The work on the signal tracking focuses on a robust normalization of the discrimination functions within the tracking loops. The algorithms are presented highlighting case by case the advantages both in terms of computational complexity, robustness and performanc

Quality Monitoring for Multipath Affected Signals Using an Extended Kalman Filter

The ability to monitor and detect any disturbances on the PRN code signals transmitted from the navigation satellite constellation is of primary importance. It is known that the tracking performance of a navigation receiver stems from the correlation property of the PRN code signals transmitted. These anomalies can be detected in several different ways, either observing the outputs of navigation user receivers, or processing the received signal within the receiver. Quality control is the process that defines how well the solution of a problem is known and in the context of navigation, it consists of assuring an agreed level of accuracy, reliability and robustness for the measurements. In this work a modified version of the conventional tracking scheme will be proposed with the aim of monitoring the quality of the measurements at the signal processing level. The proposed tracking scheme is able to give a measure of the distortion of the correlation function and consequently, of the reliability of the signal tracked. In particular the problem of multipath distortion is considered The amplitude and multipath delay can be estimated with an extension of the linear Kalman Filter which can be implemented inside the traditional DLL architecture. Simulations show that due to its prediction capability, Kalman Filter enhances the robustness of the system when weak signals are present or there is loss of lock on the signals, trading off the performance improvement with an increase in complexity of the new architecture. The recognition of a multipath corrupted signal estimating the amplitude and delay of the reflection can be used to select the more reliable pseudo-range measurements for the evaluation of the positioning equations. Mitigation of the multipath effects may be performed where the number of tracked signals is not sufficien