GNSS High Precision Systems for Cadastre: development, experiences and Galileo perspectives CLGE Plenary Workshop 29 September 2017 Roberto Capua, Flavio Ferrante DO-11-DO-03 1
Agenda GNSS High Precision Systems Evolutions The Cadastral Land Surveying applications in Italy The Sogei GRDNet Network GPS and Galileo Integrity Monitoring Systems High Precision on Smartphones Galileo Network Upgrade Conclusions and Recommendations 2
The automatic cartographic updating by Pregeo 10 Institutional Software PREGEO procedure evolution 1988 2003 2006 2009 PREGEO PREGEO 8 PREGEO 9 PREGEO 10 Circular n. 2/88 Simplification and standardization of the implementing rules of surveys and cadastral cartography updating procedures and the connected DB census archive too Digital management of cadastral cartography WEGIS Satellite technology use in surveys GPS Private Surveyors Involvment Updating files automatic transmission SISTER video Cadastral cartography automatic updating 2015 Cadastral updating files online trasmission becomes mandatory
The Italian Cadastral Maps Land Surveying Hidden points: GNSS and Topographical instruments hybridisation GNSS Baseline Cadastral Fiducial Points to be surveyed GNSS Base Point 4
Monitoring of Map Update Acts 2008 2016 GNSS Surveys 700,000 600,000 500,000 400,000 300,000 200,000 100,000 Total Map Update Acts Map Update Acts through GNSS 0 Total Map Update Acts Map Update Acts through GNSS % 2008 404 672 52 900 13 2009 385 029 72 621 19 2010 413 674 107 067 26 2011 473 572 162 931 34 2012 386 953 156 179 40 2013 259 359 114 446 44 2014 200 617 93 874 47 2015 177 705 88 256 50 2016 180 324 95 542 53
Land Cadastre Update: PreGeo Procedure Type 2 PREGEO recording Row Final point of a baseline Can record any GNSS Surveying Result!
GNSS Augmentation System Characterization 7
GRDNet (GNSS R&D Network) Deployed in 2003 for providing institutional Real-Time high accuracy positioning Currently covering the central area of Italy (15 GNSS Reference Stations) Single Station, Nearest and VRS Services Fully Standard compliant (NTRIP protocol, RTCM v3.x data format) Open and Scalar Architecture, any kind of GNSS Reference Station Internally developed GNSS Control Centre Software Web Network Performances Monitoring and Control All Reference Stations are Galileo Ready
GRDNet Architecture EGNOS/EDAS Tier-1 GNSS Reference Stations RTCM3 RIMS Raw Data NTRIP/RTCM Real-Time GPS and Galileo Precise Worldwide RS raw data Public Interconnectivity System Users RTSP to http Bridge http Front-End Protocol: NTRIP Data Format: RTCM NTRIP Specific Control Centres OBU LDS IGS NTRIP ftp RINEX files Precise orbits/ clocks Integrity Monitoring Data Storing and Integrity Back-End Tier-2 (Sardinia RSs) Data Storing 1 U Storage Integrity Network Processing GNSS Network Management and Corrections Generation Software Storage Tek
Galileo High Precision Integrity Systems within Horizon 2020 Needed in several current and emerging applications (e.g. Rail, Aviation, Automotive, Automatic Driving): Federated GNSS Network High Precision and High Integrity Augmentation Systems studied for the Rail sector (ERSAT-EAV and RHINOS GSA Projects) 2-Tiers Augmentation: integrating Local Reference Stations and EGNOS RIMS for performing GNSS Signal, Reference Stations and Augmentation Systems Fault Detection and Exclusion EGNOS EDAS RIMS Raw meas. Correction mgs SIS FDE LA FDE GNSS Augmentation Control Centre Augmentation Msgs 10
High Precision and Integrity Current GNSS RTK and Network RTK Systems limitations: High GNSS Reference Stations Maintenance and Fault recovery costs GNSS Geodetic equipments and Service Fees for Surveyors GNSS Network Service Guarantee and Fault Monitoring Reliability, Integrity and Anti-Spoofing as a Cost-Saving factor: HP System Faults (GNSS, Augmentation and Communication!) leading to longer surveying or completely new surveys Integrity as a cost-saving factor (2 persons/day+travel+elaboration): avoiding the risk of a faulted survey for GNSS or Network Faults 11
GNSS High Precision Surveying Faults HP Surveying Faults On-Field GNSS HP Network GNSS SIS: Shadowing Multipath Foliage Attenuation Ephemeris and Clock Signal Deformations Ionospheric Anomalies Interferences Spoofing Mobile Comm. (RTK) Reference Station HW Faults Control Centre Software Fault Reference Station to Control Centre Comm Faults SIS and Augmentation Fault Detection and Exclusion to be integrated within the GNSS Network Galileo CS Authentication Services (OS-NMA) Multi-Constellation benefit 12
Web Integrity Monitoring through EGNOS Available to any user 13
2-Tiers GNSS Signal and Network Fault Detection and Exclusion Available to any user Threshold for Alarm Residual Testing Real-Time Monitoring Galileo Satellite Monitoring: Lowest residuals! 14
RTCM SC-104 WG «Integrity Monitoring for High Precision applications» 17 participating RTCM Members Main objectives of the WG are: Definition of Integrity Standard messages for High Precision Applications to be inserted within the RTCM 3.x standard Definition of Guidelines for the development of High Precision and High Integrity Local Augmentation Systems Liason with other Standardization Bodies (e.g. RTCA, SAE) 15
Single-Frequency COTS Low Cost RTK Receivers Hardware Receivers: Low-Cost, Single-Frequency RTK on the Market Time To Fix Ambiguities in the order of a 4-5 minutes if: Short baselines (Physical or VRS Stations) Medium-High number of visible satellites (7-9) Dual-Frequency chipset for smartphones yet on the Market! Software Receivers/SDR (Software Dedined Radio): Full SDR: Software program on a PC or a Tablet GPS/EGNOS RTK Going toward smartphone and Galileo integration 16
High Precision for Everyone Google announced raw GNSS measurements output from smartphones and tablets running Android Nougat Smartphones Processing limitations: Bias in the carrier-phase measurements High Pseudorange noise (tens of meters) Carrier Phase affected by frequent outliers GNSS antenna uses linear polarization: weak resistance to multipath Duty cycle to be disabled for allowing continuous Phase Galileo Ready equipments still on the Market 17
High Precision on Smartphone: close to surveying Released the first Dual Frequency, multiconstellation chipset for smartphones on 21 September 2017 Signals: GPS L1/L5 GLONASS L1 Beidou B1 Galileo E1/E5a QZSS L5 Low power consumption High Precision (Code and Phase) Higher performances in Urban areas (multipath resistance, higher avaiability) We are closer to a smartphone RTK survey! 18
Precise Point Positioning (PPP) Precise Point Positioning (PPP) through a Single Receiver (no Reference Station connection) Real-Time Precise Orbits and Clocks from Augmentation Service Providers and sparse Regional/Global Reference Station Networks (low cost) Other errors to be modelled (Phase-Windup, Ocean loading and Earth tides, relativistic effects, Sagnac effect) Convergence to 10 cm in 20-40 min (no Ambiguity Fix) The next objective: Real-Time PPP-RTK and cm level positioning! PPP Control Centre Precise Orbits, Clocks, Biases Ambiguity Fix 19
High Precision on Smarthphones: where are we? Carrier smoothed+iono estimation PPP experiment in literature: Precise satellite clock and orbits Global Ionospheric Maps Relativistic effects, Earth tides modelling Ionospheric Delay local estimation App available for testing PPP Source GPS World Banville, Diggelen, 2016 Current Limitations: Battery life Pseudoranges noise Smartphone Antenna Source GPS World Banville, Diggelen, 2016 Code only: IGSRTS+SBAS Smartphone is a candidate for low cost PPP-RTK Source: BlackdotGNSS 20
Real Cadastral Map Update through SDR (ION GNSS 2016) Example of Comparison with GNSS surveys in the Cadastral DB High PDOP (>6), 5 sats, Urban Canyons, Foliage, frequent CS TFFA < 17 min Correct fixes: in the order of 75% 21
Number of satellites Improvements from Galileo for High Precision Surveying Increased Availability in Urban Areas through GPS+Galileo Satellite Visibility (Visibility mask angle = 30 ) 12 10 8 6 4 2 GPS+GALILEO 0 0 5 10 15 20 Time of Day (hours) GPS Antispoofing: OS-NMA and Commercial Authentication services on E6, increased robustness and antispoofing for professional applications Improved Multipath Resistance Istantaneous Fixing: through Galileo Third frequency (TCAR) Precise Point Positioning: broadcasting of part of PPP corrections from Galileo satellites directly (no external communication) 22
Galileo only RTK Results Galileo RTK Fixed Solution Vallermosa Villasor (Sardinia-Italy) Baseline: 12.5 Km Galileo Satellite Visibility 23
Galileo Network-RTK Control Centre Issues Network Ambiguity Resolution at Control Centre: GPS-Galileo Intersystem Biases to be estimated Galileo GTRF to other Reference Frames Conversion Frequency Extensions and Measurement record generalization Computational Burden Improved Integrity Monitoring Performances E1 Ambiguity Fixing E5 Ambiguity Fixing 7 6 5 4 E7 E8 E12 E19 E26 E30 6 4 2 E7 E8 E12 E19 E26 E30 3 2 0 1-2 0-1 -4-2 1000 1500 2000 2500 3000 3500 4000 4500 0 1000 2000 3000 4000 5000 24
ROVER/SDR NETWORK Galileo Integration RoadMap for GRDNet and SDR 25
Galileo Integration Issues and constraints for High Precision Surveying Manufacturers constraints: Most of manufacturers are integrating E1, E5a, E5b, E5 Galileo Signals E6 implemented only by one manufaturer Commercial Services ICD The use of Galileo measurements for RTK for some manufacturers is optional and subject to the payment of a firmware update Some manufacturers do not correctly decode Galileo Ephemeris (both geodetic and Mass Market receivers) Galileo Services for Network-RTK Operators: GGSP: Galileo Precise Orbits and Clocks solutions, as well as ERP parameters for PPP and Control Network Adjustment using Galileo GTRF: INSPIRE Directive recommends the use of ETRF2000 for Public Administration services; could be important having the transformation parameters from GTRF to ETRF2000 provided directly by the GGSP 26
Suggestions for improving the introduction of Galileo To involve GNSS High Precision Service Providers and Land Administrations in the Galileo Commercial Services Validation Phase (GGSP Products validation) To involve GNSS Network Operators in Galileo Broadcasting channel tests: very interesting to test the Commercial Services broadcasting capability, compliance to current RTCM standards or update to meet the available message length To help Network Operators to sustain Reference Stations firmware upgrade in the early period after Galileo FOC (Agreement with Manufacturers) EGNOS/EDAS: introduce multiple-frequency capability To promote the integration of Networks to be used for different applications (Federated Network) To ensure that Galileo for RTK is included by default by all manufacturers into their products (no additional cost for surveyors and Network Operators) 27
Conclusions and Recommendations High Precision techniques are evolving from NRTK to PPP-RTK High Integrity and Anti-Spoofing relevant for Service Guarantee GNSS Federated Augmentation Network for cost sharing Galileo relevant improvements in terms of Availability, Multipath resistance, Integrity Galileo Authentication Services for mitigating spoofing threats Galileo Broadcasting of corrections messages (RTCM MSM) for low cost PPP Dual Frequency Smartphone chipset on the Market: we are closer to Smartphone GPS+Galileo Land Surveying 28