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CSRS-PPP – Transitioning to a Modernized Positioning Service in Canada ACLS Webinar June 13, 2018. Brian Donahue, Elyes Hassen, Simon Banville Canadian Geodetic Survey, Natural Resources Canada. OUTLINE. CSRS-PPP Current State Software and Products Usage Statistics Rationale for change
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CSRS-PPP – Transitioning to a Modernized Positioning Service in CanadaACLS WebinarJune 13, 2018 Brian Donahue, Elyes Hassen, Simon Banville Canadian Geodetic Survey, Natural Resources Canada
OUTLINE • CSRS-PPP Current State • Software and Products • Usage Statistics • Rationale for change • CSRS-PPP transition plan (GPSPACE to SPARK) • Accuracy analysis • User Impact • Implementation Timeline • Future Plans
CSRS-PPP Overview NRCan or IGS NRCan GNSS Orbit & Clock Estimation GNSS Modelling and Processing CSRS-PPP Estimated Static or Kinematic Positions IGS GNSS RINEX Data Users
CSRS-PPP – GNSS Positioning Service • CSRS-PPP Service Overview (Current) • PPP Software: GPSPACE v1.05 11216 • Pre-processing: python scripts for RINEX v2 validation (RINEX v3 not processed) • Post-processing: Perl Script calling various utilities • Note: Currently uses same velocity model, geoid models, and transformation parameters as TRX and GPS-H but has separate implementations • New PPP Software (SPARK) running in parallel for validation
CSRS-PPP – GNSS Positioning Service CSRS-PPP Product Summary 1 Latency is measured from the end of the time correction period 2 Horizontal RMS was calculated from static PPP results for 114 3h RINEX observation files 3IGS repro1 – IGS reprocessing campaign where IGS Final products were updated using 2007 processing strategies. Used for solutions prior to Dec. 2007
CSRS-PPP Usage • NRCan has processed over 3 Million GNSS datasets with the CSRS-PPP service since 2003 • 2017 Usage Statistics • ~6000 unique users • Almost 600,000 datasets processed • 89% static, 11% kinematic • 99% dual frequency • 21% NAD83(CSRS), 79% ITRF • 12% CGVD2013, 88% CGVD28 (% of NAD83 solutions) • Note: 2016 user survey respondents reported satisfaction with CSRS-PPP service but some requested support for new GNSS satellite constellations
CSRS-PPP – 2018 Software Transition Why transition to SPARK? • Modern processing engine • Capable of handling all constellations and signals • Supports RINEX v3 • Single frequency code+phase solution • Pathway to PPP-AR and co-operative PPP (faster convergence = shorter observation requirements) • Completely updated pre/post-processing modules • Easier to maintain • Perl script replaced with modular Python and Java tools • RINEX validation includes support for RINEX v3 • post-processing uses common transformation libraries (GPS-H/TRX)
CSRS-PPP – 2018 Software Transition How do SPARK and PACE results compare? • Comparison of 16149 submissions (2018-04-10 to 2018-04-24) • Note: 7% of solutions failed and weren’t compared: • Reasons for failures: • Data submitted not RINEX format • Noisy data (> 90% of data rejected)
CSRS-PPP – 2018 Software Transition How do SPARK and PACE results compare? • Comparison of 13459 submissions (2018-04-10 to 2018-04-24) Solutions were flagged for further analysis if: • Static: 3D-diff > 3D standard deviation at 95% • Kinematic: RMS of vert. diffs > 5 cm
DATA CSRS-PPP – SPARK Accuracy Analysis Process Parameters • 1000 24h-observation RINEX files (sampling rate-30s) • 20 stations from CACS : 15 National - 4 WCDA -1 Regional • 52 days between January 6th and December 28th , 2016 • Reference positions : weekly IGS estimated pos. (SSC file) • Mode : Static & Kinematic • GNSS : GPS only & GPS+GLONASS • Frequency : L1+L2 • Orbits and Clocks : IGS products (finals) • Pole tide corrections (erp) • Tropospheric Zenith Delay (TZD) • Cut-off elevation : 7.5 • Ant/sat offsets : ATX/SVB files • Tropospheric gradient estimation • Ocean Loading OTL * PACE version1.05 11216 ------ SPARK version 2.1.0 (r421) * Data processed between April 9th and April 14th, 2018
CSRS-PPP – SPARK Accuracy Analysis Results Static - GPS + GLONASS 1H 1:00 1:00 Height bias : Correction for signal curvature due to gravity – not applied by PACE 1:00
CSRS-PPP – SPARK Accuracy Analysis Results Static - GPS + GLONASS 1H 1:00 1:00 1:00
CSRS-PPP – SPARK Accuracy Analysis Results Static - GPS + GLONASS 3H
CSRS-PPP – SPARK Accuracy Analysis Results Static - GPS + GLONASS 3H
CSRS-PPP – SPARK Accuracy Analysis Results Static - GPS + GLONASS 24H
CSRS-PPP – SPARK Accuracy Analysis Results Static - GPS + GLONASS 24H
CSRS-PPP – SPARK Accuracy Analysis Results Kinematic – GPS + GLONASS – Obs time : 1h RMS of estimated positions over all epochs
CSRS-PPP – SPARK Accuracy Analysis Results Kinematic – GPS + GLONASS – Obs time : 3h RMS of estimated positions over all epochs
CSRS-PPP – SPARK Accuracy Analysis Results Kinematic – GPS + GLONASS – Obs time : 23h45 RMS of estimated positions over all epochs
CSRS-PPP – SPARK Accuracy Analysis • Accuracy analysis conclusions • Validated accuracy of new CSRS-PPP engine • SPARK 24h static solutions were within 2mm horizontal and 4mm vertical of truth • Confirmed equal or better quality SPARK vs. PACE • Horizontal equivalent (< 1mm) • Vertical 4-5mm bias in PACE • 20 – 30% improvement in kinematic solutions with SPARK
CSRS-PPP – 2018 Software Transition What will be the impact on users? Submission interfaces will not change (web, PPP direct, Python script)
CSRS-PPP – 2018 Software Transition What will be the impact on users? • Some outputs will change • Summary file (.sum) will be the most significant change • MTM outputs for Canadian NAD83 solutions will now be merged directly into original sum and pos files SPARK: Summary of results HTML PDF report PDF Summary file (txt) .sum Position file (txt) .pos Position file (csv) .csv Help file (txt) .txt Residuals .res PACE: Summary of results HTML PDF report PDF Summary file (txt) .sum Position file (txt) .pos Position file (csv) .csv Residuals .res MTM.sum (Canada only, NAD83) MTM.pos (Canada only, NAD83) full_output.zip res.zip
PACE SPARK
SPARK summary text file (.sum) 3-character codes
SPARK summary text file (.sum) POS- positions (including ref system, epoch, apriori, estimate, and sigma) PRJ – projected coordinates for UTM and MTM OHT – orthometric height
CSRS-PPP – 2018 Software Transition • User Impact Summary • Improvement of 4-5mm in height • No differences to submission applications • Some outputs slightly changed (e.g. PDF report) • Summary text file (.sum) completely updated with 3 character codes • Residual file format still under consideration
CSRS-PPP – 2018 Software Transition What is the timeline for transitioning? • Mid-2017 to present – SPARK running in parallel • Developed new reporting tools • New preprocessing and solution validation modules • Completed several accuracy analysis solutions • On-going submission analysis and SPARK improvements • June 2018 – Communicate transition details to clients • Various presentations • Direct mail notice coming • Updating website information • Beta testers • Late July 2018 – Implement switchover and continue to run PACE in parallel
Future Plans - Towards Fast Convergence Nextstep for CSRS-PPP service Satellite orbit and clock corrections Standard PPP + Satellite code and phase biases (Decoupled-Clock Model) PPP with ambiguity resolution (PPP-AR) Optional regional network Ionosphere (STEC) Permanent reference stations User Rapid PPP convergence / Improved single-frequency solutions
PPP-AR Precision (24h Static Solutions) Nearly 40 stations in eastern Canada-US processed over a 10-year period. This plot shows the repeatability of daily positions after removing linear and seasonal trends. AR improves east component by ~30%
PPP-AR Convergence Analysis 7 days of data: August 14-20 2016 ~40 globally distributed stations using 30-sec data divided in hourly sessions 4 solutions analyzed:
PPP-AR Convergence Results Only 12 Block IIF satellites in orbit
Acknowledgements • CSRS-PPP Operations & Transition Team • Simon Banville • Justin Farinaccio • Elyes Hassen • Omid Kamali • François Lahaye • Philippe Lamothe • Hieu Nguyen • Eliane Tessier
Questions? General information Web: webapp.geod.nrcan.gc.ca Email: nrcan.geodeticinformationservices.rncan@canada.ca