Jaron Samson

Innovative interference mitigation approaches: Analytical analysis, implementation and validation

This paper focuses the attention on the problem of Radio Frequency Interference (RFI) mitigation in the framework of GNSS. The paper concentrates on interference mitigation algorithms to be applied within the digital part of a GNSS receiver. The first part of the paper focuses on the mitigation of RFI based on Wavelets. The theoretical fundamentals of the approach are presented, introducing the continuous and the discrete wavelet transformations, and its application to the mitigation of pulsed interferences is demonstrated. The mitigation of strong pulses as well as of low power Distance Measurement Equipment (DME) pulses is discussed and the results obtained for both the cases are presented. In the second part of the paper the mitigation of Continuous Wave Interference (CWI) by means of Notch Filtering is studied, presenting the fundamental steps of this method and presenting its benefits by means of simulation results.

Experimental assessment of Distance Measuring Equipment and Tactical Air Navigation interference on GPS L5 and Galileo E5a frequency bands

This paper will provide an experimental assessment of Global Navigation Satellite System (GNSS) receiver operations under interference generated by other Aeronautical Radio Navigation Systems (ARNS) such as Distance Measuring Equipment (DME) and Tactical Air Navigation (TACAN) transmitting within the GPS L5 and Galileo E5a frequency bands. In detail, results in terms of C/N0 degradation and error on the pseudorange measurements will be presented. Afterwards, an innovative interference mitigation technique will be introduced and its benefits against the aviation interference environment considered, will be assessed at receiver level by means of software implementation and simulation. Finally, a quick analysis of the potential DME/TACAN interference impact on GNSS receiver in demodulating the Space Based Augmentation System (SBAS) navigation messages, will be described.

Impact of high-end receivers in a peer-to-peer cooperative localization system

This paper introduces the concept of peer-to-peer cooperation as an aiding technique in GNSS positioning and addresses the impact of the presence of professional receivers in the network. The impact of their higher accuracy is evaluated for the cases of both GNSS-data only and hybrid data exchange. Kalman Filters are considered as the data fusion engine.

Description of an Interference Test Facility (ITF) to assess GNSS receivers performance in presence of interference

The E5 and E6 bands, which will be used by Galileo, will have to be shared with many ground-based applications in the aeronautical, communications and military domains. It becomes crucial to evaluate the effects of interference from terrestrial sources on the performance of GNSS Receivers. In order to solve this issue, the data recording in different locations (e.g. urban, rural and airport) in addition to the ability to replay and generate GNSS signals with identified interference may help the investigation of advanced interference mitigation techniques and the testing of their implementation in the receivers. The objective of this paper is to present the Interference Test Facility (ITF), a test-bed to assess GNSS receiver performance in presence of interference. This project aimed at developing an interference test facility to be used to generate (simulate or replay) interference and to assess the performance of the GNSS receivers when they have to face an intentional or non intentional interference. The paper introduces the hardware description of the ITF platform and its main functionalities. The paper addresses also a panorama of the potential interference signals in the GPS and Galileo bands and a test campaign that was performed to collect data representative of the interferences that may impact the GNSS receivers in various environments (urban, airport, etc.). This data collection was used further in the ITF project during the validation phase in order to demonstrate the capacity of the ITF platform to replay real interference signals. This validation consisted in demonstrating the equivalence of the impact of simulated and real interference.

Distributed-weighted multidimensional scaling for hybrid Peer-to-Peer localization

This paper presents a hybrid localization algorithm for a Peer-to-Peer (P2P)-Positioning scenario, where “peers” are devices equipped with both a GNSS (Global Navigation Satellite System) receiver and a wireless communications interface. Through their GNSS receiver, peers obtain pseudorange estimates from satellites while they use their wireless interface both to communicate with each other and to obtain terrestrial range estimates. The proposed algorithm is an extended version of the distributed-weighted multidimensional scaling (dwMDS) [1] algorithm to be compatible with the hybrid P2P scenario where unknown peers infer their own positions by fusing both GNSS pseudorange and terrestrial range estimates. Simulation results show that the proposed hybrid dwMDS (hdwMDS) algorithm out-performs the cooperative version of the least squares algorithm. Moreover, they show the related benefits in term of positioning performance in a cooperative scenario in comparison to a non cooperative one based on GNSS-only positioning.

Indoor positioning in peer-to-peer networks

We present two algorithms for indoor positioning in peer-to-peer networks. The setup is a network of two types of devices: reference devices with a known location, and user devices that can determine distances to reference devices and each other. We present two algorithms for positioning estimation in such a peer-to-peer network. The first one is purely geometric and reduces determining the best estimate for the position of a device to a least squares problem. The second approach can be considered as a probabilistic version of the geometric approach. We estimate the probability density function that a device is located at a position, given a probability density function for the positions of the other devices in the network, and a probability density function of the measured distances.

Improved GNSS positioning exploiting a vehicular P2P infrastructure

This paper considers the possibility to exploit external altitude measurements to improve the performance of a Kalman based GNSS receiver. The altitude measurements are provided by means of a peer to peer network, that is supposed to be based on the evolution of the 802.11 standard for the vehicular environment, namely the WAVE (802.11p). The performance of such a system are investigated for different characteristics of the aiding measurement and for a different number and disposals of the aiding peers. The aiding measurement is obtained starting from the altitude measurements that the other peers in the network send to the aided user. The experiments highlight the need for a parameter that points out the effectiveness and the consistency of the computed aiding measurement, taking into account many parameters such as the number of peers, their distribution in the user cluster and the number of satellites available for the solution computation. To this purpose, a reliability index is defined and the performance of a system that relies on this index are shown.