Heidi Kuusniemi

Performance analysis of a multi-GNSS receiver in the presence of a commercial jammer

In addition to the two existing Global Navigation Satellite Systems (GNSS) GPS and GLONASS, there are two other emerging GNSS constellations Galileo and BeiDou that will offer global coverage sometime within the end of this decade. These redundant multiple constellations transmitting civilian signals in different frequency bands will offer immense possibilities to improve navigation performance in terms of availability, reliability, accuracy and so on. In this paper, the authors analyze the performance of their implemented multi-frequency multi-GNSS software-defined receiver in two different cases: a good Line-Of-Sight (LOS) condition i) without the presence of any intentional jamming, and ii) in the presence of a commercial L1 jammer. The objective here is to analyze the performance of the multi-GNSS receiver in an ideal LOS condition, so the benefits of multi-GNSS could be straightaway realized. In addition to this, the second objective is to highlight one of the key benefits that a multi-frequency multi-GNSS receiver can offer in the occurrence of jamming in one of its frequency bands. To this end, the authors implemented a modified interference detection method based on the level changing rate of the Running Digital Sum (RDS) of the raw data bins. A simple jamming detection based GNSS signal selection mechanism is implemented. It is shown in the paper that the jamming detection based GNSS signal selection mechanism offers a much improved navigation performance than a straightforward multi-GNSS solution.

Operational Scenarios for Maritime Safety in the Baltic Sea: Operational Scenarios for Maritime Safety

The project Enhanced Situational Awareness to Improve Maritime Safety in the Baltic (BONUS ESABALT) is a research and development project funded by the BONUS program for studying the feasibility of a novel system for enhancing maritime safety, focusing on the Baltic Sea as a test-bed for the system and service concept. In this paper, we describe the system architecture for the proposed ESABALT concept. Next, we describe few maritime scenarios in which the proposed system can be beneficial. These scenarios can be grouped under three specialized services of intelligent marine navigation and routing information, efficient emergency response, and environmental monitoring and reporting with emphasis on cross-border cross-sector functionality. The paper also summarizes the test and maritime data collection campaign performed onboard the Viking Line’s cruise ship ‘Amorella’, operating on the Turku – Stockholm – Turku route. The aim of this exercise was to collect data generated by the ship’s own electronic systems, and also to determine the availability and performance of navigation and communication signals along the maritime route. Analysis of this data is expected to enable distillation of the most critical information for crowdsourcing in the maritime scenario. Finally, we discuss the expected societal and economic impact of the proposed system in the Baltic Sea Region maritime domain.

Performance Analysis of a Dual-Frequency Software-Defined BeiDou Receiver with B1 and B2 Signals

The Chinese BeiDou Navigation Satellite System (BDS) is one of the fastest emerging Global Navigation Satellite Systems (GNSS) that offers two civilian navigation signals through its 14 operational satellites as of November 2014. The release of the 2nd version of the BeiDou Interface Control Document (ICD) in December 2013 makes it possible for the researchers worldwide to investigate the performance of the 2nd civilian BeiDou B2 signal along with the legacy BeiDou B1 signal. In this paper, the researchers at the Finnish Geospatial Research Institute (FGI) make an effort to analyze the performance of BeiDou B1 and B2 signals in Finland considering the similarities and differences between the signals that affect the final positioning result. The performance analysis is carried out in a software-defined multi-frequency multi-GNSS research receiver developed at FGI. The data collection and the result analysis are carried out in two steps. In the first step, a hardware multi-frequency multi-GNSS simulator is utilized to verify the performance of the developed software-defined receiver. Afterwards, in the second step, the performance evaluation of BeiDou B1 and B2 signals is carried out with live data sets.

Proof-of-concept demonstrator to Improve Safety of Maritime navigation in the Baltic Sea

This paper describes the proof-of-concept demonstrator implemented as part of the project Enhanced Situational Awareness to Improve Maritime Safety in the Baltic (BONUS ESABALT). The demonstrator represents the system as used in different classes of vessels including leisure craft (small boats), larger ships, and authority vessels. Various validation scenarios are implemented to demonstrate the system functionality, for example application of ESABALT to aid in recovery operations after an oil spill, rerouting in the presence of significant sea-ice, aiding vessel navigation in case of a GNSS interference event, and situations where multiple ships are in distress. The demonstrator is implemented on a laptop computer and using the FURUNO FFSC-200 software environment, FURUNO Finland FICE-100 ice radar and FOIL-200 oil radar, live ship data from AIS receivers, dashboard camera, and the FURUNO Navisimu simulator environment. The simulated data include AIS tracks, radar echo and tracks, and small boat tracks. The paper also describes the implementation challenges, quality of service factors, and results of the economic and non-economic viability analysis of the proposed ESABALT system for potential full-implementation in the future. This study shows that the system would be cost-effective and the benefits to international cooperation, maritime safety, and environmental monitoring would outweigh the management costs necessary to sustain it.

Effect of antenna location on GNSS positioning for ITS applications

The proliferation of GNSS-receiving mobile devices in the consumer market and the growth of the Intelligent Transportation Systems sector have raised a lot of interest in low-cost precise positioning. However, GNSS signal quality is degraded inside the metal body of a vehicle, which is where the antenna of a portable device is to be located. This article investigates the effect of antenna location on precise low-cost GNSS positioning for a road vehicle. We compare a roof-mounted GNSS receiver with an identical receiver having the antenna on the dashboard and a tailored smartphone also located inside the cabin; both the availability of raw carrier phase measurements and the resulting horizontal precise point positioning accuracy are evaluated. The test results show that the 90 % circular error probable is degraded by several meters inside the vehicle. Moreover, most of the evaluated accuracy metrics indicate that the low-cost GNSS receiver with antenna inside the cabin achieved a positioning accuracy at least 50 % better than the smartphone located next to it when using the same satellite systems.

Performance comparison of differential GNSS, EGNOS and SDCM in different user scenarios in Finland

Positioning errors of stand-alone GNSS can be reduced with different real-time augmentation approaches. For many navigation and positioning applications, Satellite-Based Augmentation System (SBAS) and Differential code-based GNSS (DGNSS) can offer substantial improvement in the positioning accuracy. Finland is covered by EGNOS (European Geostationary Overlay Service) even though it is lying at the north-east margin of the coverage area. In addition to EGNOS, the neighboring SBAS system SDCM (System for Differential Corrections and Monitoring) has monitoring stations near Finland. In this work, the researchers at the Finnish Geospatial Research Institute (FGI) conducted some field experiments with mentioned SBASs and National Land Survey of Finlands (NLS) DGNSS service in order to find out reachable accuracies and rough estimates of availability in varying positioning conditions. Interest to SDCM grew due to its vicinity from Finland and also partly due to its ability to provide GLONASS corrections which EGNOS has not yet been able to offer.