GNSS Signal Quality Monitoring in Finland (GNSS-Finland) Presenter: Dr. Zahidul Bhuiyan Department of Navigation and Positioning Finnish Geospatial Research Institute National Land Survey of Finland
GNSS-Finland Project – In a Nutshell ▪ Main Objective: To monitor GNSS signal quality information in Finland as perceived by Finnish National Reference Network (FinnRef) of 47 stations ▪ Project Duration: 5 months (February’ 2019 – June’ 2019) ▪ Project Funder: Finnish Transport and Communications Authority (Traficom) ▪ Project Coordinator: Finnish Geospatial Research Institute, National Land Survey of Finland GNSS Signal Quality Monitoring in Finland @’GNSS Interference’ Seminar 2
Background Information ▪ GNSS-Signal Quality Evaluation in Finland – a preliminary study was conducted in 2017 in order to portray an overall picture of user requirements for GNSS signal quality monitoring in Finland ▪ Over 2000 persons were contacted – 398 responded to web-survey and 4 in-person interviews were conducted ▪ The results showed that a significant majority of the respondents would benefit or definitely benefit from knowing the current status of GNSS/EGNOS over Finland ▪ Final Report on ” GNSS Signal Quality Evaluation in Finland – Preliminary Study ” can be downloaded from Ministry of Transport and Communications’ website. GNSS Signal Quality Monitoring in Finland @’GNSS Interference’ Seminar 3
End Users Perspective on Benefits of the GNSS-Finland service ▪ It would provide users a cost-effective and reliable source of information as compared to more expensive commercial services It would help to identify areas affected by intentional signal jamming, if there is any ▪ ▪ It would help users to plan the most optimum time and place to perform their GNSS- enabled field operations in Finland , by avoiding expected signal degradation or disruption time windows It would help users to effectively know the magnitude of the errors in the measurements ▪ already taken ▪ It would help users build new applications and services based on this information ▪ It would help users to notify their own customers of upcoming or ongoing disruptions ▪ Potential for outreach to uninformed users , thus helping to increase the uptake of EGNSS-enabled solutions into their products and services. GNSS Signal Quality Monitoring in Finland @’GNSS Interference’ Seminar 4
Rationale for GNSS-Finland Project - GNSS-Finland will use the Finnish National GNSS network “FinnRef” for monitoring GNSS signal quality over Finland. Once implemented, the service can offer near real-time updates about the GNSS status and historical trends. - Similar services exist in other countries, however we need a service dedicated to and owned by Finland. - GNSS information is also not monitored at this level of detail from other national agencies - Critical infrastructures that depends on GNSS for its positioning or timing requirements should be equipped with interference monitoring, detection, and alert service, and also should have alternative non-GNSS back-up solution GNSS Signal Quality Monitoring in Finland @’GNSS Interference’ Seminar 5
Finnish National Reference Network (FinnRef) ▪ 47 CORS → Basis for the national reference frame, EUREF-FIN, few stations also serve as IGS stations, and also co-located with EGNOS RIMS ▪ All GNSS and multiple frequencies are observed ▪ Real-time positioning service ‘FINPOS’ uses FinnRef data to provide DGNSS, Network RTK measurement data ▪ Data format available in RINEX and real-time streams (RTCM MSM (GPS+GLO+GAL+BDS) GNSS Signal Quality Monitoring in Finland @’GNSS Interference’ Seminar 6
GNSS-Finland: Process Flow FinnRef stations RTCM messages (47) Raw observations True position Signal strength User Interface: Doppler GNSS Data analysis Pseudoranges Carrier-phase Health Flags PVT computation Quality Measurement Index - Signal strength degradation - Position deviation - Signal level fault - System level fault GNSS Signal Quality Monitoring in Finland @’GNSS Interference’ Seminar 7
GNSS-Finland: Architectural Overview RTCM GNSS-Finland service FinnRef stations service Windows console app (47) C++ Connector Data transfer library C++ <=> Java Users Frontend Server Web application Server application JavaScript (ES6) Java Database Postgres GNSS Signal Quality Monitoring in Finland @’GNSS Interference’ Seminar 8
Features of GNSS-Finland (1/2) ▪ The core software is implemented in C++, Java and JavaScript utilizing Spring Framework and React.js library ▪ The data storage is based on PostgreSQL and PostGIS. ▪ Connects to the real-time RTCM data streams for all FinnRef stations ▪ Reads and decodes the retrieved messages in near real time ▪ Provides transparent interaction between GNSS Finland Service and the back-end Server ▪ Supports RTCM 3.x data standard, NTRIP over TCP/IP communication protocol ▪ Performs PVT computation for all stations (have not yet tested for all 47 stations) GNSS Signal Quality Monitoring in Finland @’GNSS Interference’ Seminar 9
Features of GNSS-Finland (2/2) ▪ Can offer GPS-only and Galileo-only PVT solution ▪ Position deviation at individual FinnRef station ▪ Periodically sends data to the server ▪ Interference detection algorithm based on the degradation on the received GNSS signal strength ▪ Two levels of users: 1. General User: can view generic monitoring information 2. Authenticated User: will have access to a more sophisticated service (mostly intended for public regulatory authorities) ▪ Provision for automatic alerting to authenticated user in case of any anomaly detection on GNSS signals GNSS Signal Quality Monitoring in Finland @’GNSS Interference’ Seminar 10
GNSS-Finland Service (Main View) ▪ Overall Signal Quality status over Finland using color-coded FinnRef stations ▪ Green – GNSS signal quality is excellent, ▪ Yellow – GNSS signal quality is satisfactory, ▪ Red – GNSS signal quality is poor. ▪ Grey – Station data is not processed. GNSS Signal Quality Monitoring in Finland @’GNSS Interference’ Seminar 11
GNSS-Finland Service (Station view): Position Accuracy Tab ▪ Shows site-specific monitoring information in more details: ▪ Position deviation ▪ Average C/N 0 of all tracked satellites ▪ Number of visible satellites ▪ Number of satellites used in position fix ▪ Doppler GNSS Signal Quality Monitoring in Finland @’GNSS Interference’ Seminar 12
GNSS-Finland Service (Station View): Signal Quality Tab (1/2) ▪ Shows average C/N 0 for all GPS satellites and Galileo satellites separately ▪ Interference monitoring status: ‘ No interference detected ’ / ‘ Interference detected! ’ GNSS Signal Quality Monitoring in Finland @’GNSS Interference’ Seminar 13
GNSS-Finland Service (Station View): Signal Quality Tab (2/2) ▪ A simulated interference scenario in order to test interference detection algorithm GNSS Signal Quality Monitoring in Finland @’GNSS Interference’ Seminar 14
Future Steps ▪ GNSS signal quality monitoring for other signals – GLONASS, BeiDou ▪ Signal quality monitoring for multiple frequencies: GPS L1, L5, Galileo E1, E5, etc. ▪ EGNOS signal quality monitoring ▪ DGNSS correction data monitoring ▪ Automatic email alert to authorized user for signal anomaly detection (in case of global-scale jamming or spoofing detection) ▪ Historic trend analysis of GNSS data at a given time frame at a given station ▪ Ionospheric status monitoring ▪ Automatic fault classification: (system-specific fault, signal-specific fault, service-level fault, etc.) ▪ Possibility to include any new CORS station within the GNSS-Finland service GNSS Signal Quality Monitoring in Finland @’GNSS Interference’ Seminar 15
State-of-the-art Services in the World List of References 1 [ALBERDING] Germany https://www.alberding.eu/en/GNSSStatus.html 2 [Leica SpiderQC] Sweden http://leica-geosystems.com/products/gnss-systems/software/leica-spiderqc http://hds.leica-geosystems.com/en/Leica-GNSS-QC- 3 [Leica GNSS QC] Sweden Software_29436.htm?pagemode=print 4 [DLR – SWACI] Germany http://swaciweb.dlr.de/data-and-products/public/tec/tec-eu/?L=1 5 [SeSolstorm] Norway http://sesolstorm.kartverket.no/ 6 [SGO] Finland http://www.sgo.fi/index.php 7 [ESSP-EGNOS] EU https://egnos-user-support.essp-sas.eu/new_egnos_ops/index.php 8 [SWEPOS] Sweden https://swepos.lantmateriet.se/ 9 [ROB] Belgium http://gnss.be/ the project was shut down some months ago as EUROCONTROL stopped funding 10 [EDCN] EU it 11 [EUREF] EU http://epncb.oma.be/ [Trimble GNSS 12 USA http://www.gnssplanningonline.com/ planning] [US Coast Guard 13 USA http://www.navcen.uscg.gov/?pageName=GPSmain NavCen] 14 [AUGUR] EU http://augur.ecacnav.com/augur/app/home [NOAA Space 15 Weather Prediction USA http://www.swpc.noaa.gov/ Center] 16 [EuGSC] EU https://www.gsc-europa.eu/system-status/Constellation-Information
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