1. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 1 / 37 GNSS: how should we measure parcels in 2010 ? Cozmin LUCAU, Krasimira GANISHEVA, Beata HEJMANOWSKA GeoCAP, JRC Ispra

2. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 2 / 37 Outline 1.GNSS …. overview 2.Research objectives 3.Field measurements 4.Results for area measurement and point position accuracy  impact of corrections: EGNOS, DGPS  impact of measurement method: continuous, stop&go, vertex 5.Conclusions & perspectives

3. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 3 / 37 Outline 1.GNSS …. overview 2.Research objectives 3.Field measurements 4.Results for area measurement and point position accuracy  impact of corrections: EGNOS, DGPS  impact of measurement method: continuous, stop&go, vertex 5.Conclusions & perspectives

4. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 4 / 37 1. GNSS …. overview STANDALONE GNSS 1 & 2 CARRIER PHASE CODE GPS GAGAN MSAS GLONASS WAAS GALILEO EGNOS POST-PROCESSING DGPS REAL-TIME DUAL FREQUENCY L1 VERTEX STOP&GO CONTINUOUS L1/L2 EUPOS IGS EUREF RINEX RADIO GSM 300 € 10 000 € SINGLE FREQUENCY COMPASS

5. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 5 / 37 1. GNSS …. overview STANDALONE GNSS 1 & 2 CARRIER PHASE CODE GPS GAGAN MSAS GLONASS WAAS GALILEO EGNOS POST-PROCESSING DGPS REAL-TIME DUAL FREQUENCY L1 VERTEX STOP&GO CONTINUOUS L1/L2 EUPOS IGS EUREF RINEX RADIO GSM 300 € 10 000 € SINGLE FREQUENCY COMPASS Several measurements methods Several types of receivers Several measurement modes … … … Global Navigation Satellite Systems

6. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 6 / 37 1. GNSS …. overview Specific needs Adapted tool

7. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 7 / 37 1. GNSS …. overview GNSS receiver complexity (price) Area measurementGNSS 100 € 15 000 €

8. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 8 / 37 1. GNSS …. overview Measurement mode standalone EGNOS DGPS - real time - post-processing GPS 24 (32) satellites GLONASS 18 (25) satellites 2(3) satellites + ground stations EUPOS (http://www.eupos.org/) EUREF (http://www.epncb.oma.be/) National/regional/local networks (IGN, RENAG, GPSLombardia, FLEPOS, etc.) GALILEO 2014  30 satellites GNSS receiver complexity (price) Area measurementGNSS

9. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 9 / 37 1. GNSS …. overview Measurement mode standalone EGNOS DGPS - real time - post-processing GNSS receiver complexity (price) Measurement method continuous stop&go vertex time / accuracy (2-3 min vs 6-7 min) Area measurementGNSS

10. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 10 / 37 Outline 1.GNSS …. overview 2.Research objectives 3.Field measurements 4.Results for area measurement and point position accuracy  impact of corrections: EGNOS, DGPS  impact of measurement method: continuous, stop&go, vertex 5.Conclusions & perspectives

11. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 11 / 37 2. Research objectives better understanding of GNSS to increase the performances of field measurement (area estimation AND boundary position) LPIS update ?? Correct area estimation !!! !!! Wrong boundary position !!! BUT ? ? ?

12. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 12 / 37 2. Research objectives assessment of GNSS measurement mode on area measurements results  STANDALONE  EGNOS  DGPS better understanding of GNSS to increase the performances of field measurement (area estimation AND boundary position) assessment of GNSS measurement method on area measurements results  CONTINUOUS  STOP&GO  VERTEX assessment of point position accuracy impact on area measurements results

13. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 13 / 37 Outline 1.GNSS …. overview 2.Research objectives 3.Field measurements 4.Results for area measurement and point position accuracy  impact of corrections: EGNOS, DGPS  impact of measurement method: continuous, stop&go, vertex 5.Conclusions & perspectives

14. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 14 / 37 3. Field measurements - 3 fields: A, B, C (± same area but different shapes and visibility conditions)

15. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 15 / 37 3. Field measurements A: regular shape, with trees mask on South part B: regular shape, with good visibility

16. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 16 / 37 3. Field measurements A: regular shape, with trees mask on South part

17. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 17 / 37 3. Field measurements B: regular shape, with good visibility

18. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 18 / 37 3. Field measurements C: irregular shape with good visibility

19. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 19 / 37 3. Field measurements - 3 fields: A, B, C (± same area but different shapes and visibility conditions) Reference position of each point was measured using Trimble 5700 with Zephyr antenna in RTK mode (estimate horizontal accuracy < 1 cm) A: 8 points B: 6 points C: 28 points

20. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 20 / 37 3. Field measurements - 3 fields: A, B, C (± same area but different shapes and visibility conditions) Pegs used for key points materialization on the field.

21. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 21 / 37 3. Field measurements - 3 fields: A, B, C (± same area but different shapes and visibility conditions) For C field, between C5 and C6 points, no pegs installed (grass border used). For C field, vertex/stop&go method the operator decides which point needs to be measured to preserve the shape of the feature.

22. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 22 / 37 3. Field measurements - 3 fields: A, B, C (± same area but different shapes and visibility conditions) - 2 GeoXT receivers: one standalone – GeoXT 1 (2005 series) and one using EGNOS corrections – GeoXT 2 (2008 series) recording data simultaneously by 2 operators standalone logging interval: 1s SN ratio: 39 max PDOP: 6.0 elevation mask: 15˚ EGNOS corrections logging interval: 1s SN ratio: 39 max PDOP: 6.0 elevation mask: 15˚ Same configuration EXCEPT recording mode GeoXT 1GeoXT 2 ????? 2005 series2008 series

23. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 23 / 37 3. Field measurements - 3 fields: A, B, C (± same area but different shapes and visibility conditions) - 2 GeoXT receivers: one standalone – GeoXT 1 (2005 series) and one using EGNOS corrections – GeoXT 2 (2008 series) recording data simultaneously by 2 operators - 3 sets of measurements, each set with 4 repetitions (CW and ACW) : - first continuous (A, B, C), - then Stop&Go (1 sec per point) / vertex (5 sec per point), (A, B, C) Each set was carried out at different time period in order to cover at more large satellites conditions; Satellite configuration stable for a given set, max 35 minutes for C field (17 points for stop&go/vertex method) * - stop&go method included

24. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 24 / 37 3. Field measurements - 3 fields: A, B, C (± same area but different shapes and visibility conditions) - 2 GeoXT receivers: one standalone – GeoXT 1 (2005 series) and one using EGNOS corrections – GeoXT 2 (2008 series) recording data simultaneously by 2 operators - 3 sets of measurements, each set with 4 repetitions (CW and ACW) : - first continuous, - then Stop&Go (1 sec per point) / vertex (5 sec per point) Each set was carried out at different time period in order to cover at more large satellites conditions; Satellite configuration stable for a given set, max 35 minutes for C field (17 points for stop&go/vertex method) - both standalone and EGNOS corrected data were post-processed using our base station data  4 data sets DGPS 2 (GeoXT 2) DGPS 1 (GeoXT 1) EGNOS corrected (GeoXT 2) standalone (GeoXT 1) 4 data sets

25. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 25 / 37 3. Field measurements: summary - 3 fields: A, B, C - 2 GeoXT receivers: one standalone, one using EGNOS corrections recording data simultaneously* by 2 operators - 3 sets of measurements, each set with 4 repetitions (CW and ACW) : - first continuous, - then Stop&Go (1 sec per point) / vertex (5 sec per point) 2 measured data sets (stand alone & EGNOS)  4 data sets (with post processing) * - for continuous mode the operators are at 2-3 meters one after other and for stop&go/vertex method the recording of the data was carried out on neighbors points.

26. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 26 / 37 Outline 1.GNSS …. overview 2.Research objectives 3.Field measurements 4.Results for area measurement and point position accuracy  impact of corrections: EGNOS, DGPS  impact of measurement method: continuous, stop&go, vertex 5.Conclusions & perspectives

27. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 27 / 37 4. Results A. Area measurement: continuous method For continuous method the impact of corrections (DGPS) is visible but not very consistent StandaloneEGNOSDGPS1DGPS2 EGNOS corrections does not improve the result Outliers eliminated

28. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 28 / 37 4. Results A. Area measurement: vertex / stop&go method StandaloneEGNOSDGPS1DGPS2 The vertex method is more accurate than stop&go, except when EGNOS is used With EGNOS, vertex (5s) = stop&go (1s)

29. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 29 / 37 4. Results A. Area measurement: continuous versus vertex / stop&go StandaloneEGNOSDGPS1DGPS2 Use continuous method with Use vertex method EGNOS DGPS Use stop&go method EGNOS DGPS standalone

30. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 30 / 37 4. Results A. Area measurement ContinuousStop&GoVertex For stop&go and vertex methods, use differential correction (EGNOS and DGPS)

31. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 31 / 37 4. Results A. Area measurement : multi-year results for GeoXT receivers StandaloneEGNOSDGPS In 2009 and 2010 tests same trend for continuously recorded data using EGNOS corrections In 2004 – no standalone data

32. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 32 / 37 4. Results A. Area measurement : EGNOS impact on area measurement, continuous method, using different GNSS receivers StandaloneEGNOS Improvement of results is visible for THALES receiver (tested in 2004) For Leica GS20 the improvement exist but it is not significant (tested in 2004) For GeoXT the impact of EGNOS corrections it is not visible (tested in 2009 and 2010) In 2004 - no standalone data for GeoXT - tests carried out during different periods

33. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 33 / 37 4. Results A. Point position accuracy Standalone < EGNOS < DGPS Stop&Go < Vertex StandaloneEGNOSDGPS1DGPS2 For stop&go and vertex method the impact of DGPS corrections on point accuracy is significant. Results from parcel A (8 key points, n = 12 / point)

34. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 34 / 37 Outline 1.GNSS …. overview 2.Research objectives 3.Field measurements 4.Results for area measurement and point position accuracy  impact of corrections: EGNOS, DGPS  impact of measurement method: continuous, stop&go, vertex 5.Conclusions & perspectives

35. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 35 / 37 5. Conclusions & perspectives A. Area measurement - using continuous method the impact of corrections (EGNOS, DGPS, etc.) is limited  OK for standalone mode, different results f. of receiver and conditions - use of corrections (EGNOS, DGPS, etc.) for Stop&Go / vertex methods improves significantly the results Differential corrections improve results in term of area measurement and absolute positioning Several base stations networks exists We can use same receiver in : - standalone mode, continuous method for area measurement - EGNOS or DGPS mode, vertex method for point measurement B. Point position accuracy - in term of absolute positioning the differential corrections improves significantly the results - using EGNOS corrections the results are few improved EGNOS  more tests !!!!

36. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 36 / 37 5. Conclusions & perspectives A. Area measurement -repeat test using other GNSS receivers (Leica, Garmin, etc.) -analyze impact of shape, mask, etc … B. Point position accuracy -analyze the impact of point accuracy on area measurement taking into account size and shape of parcel -propose a protocol to validate GNSS devices for point position accuracy (function of measurement mode, etc …)

37. Control Methods Workshop 2010 campaign, Ispra 13-15 April 2010 37 / 37 Thank you for your attention!