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Master Thesis Final Presentation: Ionosphere monitoring in GBAS using Dual Frequency GNSS measurements

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The motivation: Detection of different Ionosphere gradients, which cause different ionospheric delays in aviation applications (GBAS)
The objectives: First, estimate the airborne and ground ionospheric delays and second, monitor the ionospheric. Bias between both estimates and compare it to a threshold
The contribution: Present a GBAS Ionospheric monitor monitor that allows to estimate the ionospheric differential delay without moving to a whole Dual-Frequency GBAS concept.

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Master Thesis Final Presentation: Ionosphere monitoring in GBAS using Dual Frequency GNSS measurements

  1. 1. Ionosphere monitoring in GBAS using dual frequency GNSS measurements Joan Erencia Guerrero Supervisors: Thomas Dautermann (DLR) Michael Felux (DLR) Gabriele Giorgi (TUM)
  2. 2. 2 Ionosphere monitoring in GBAS using DF measurements INTRODUCTION Satellite Subsystem Satellite Subsystem GBAS differential GNSS approach and landing Airborne Subsystem Airborne Subsystem Ground Subsystem Ground Subsystem Aviation Benefits: Safety, efficiency, capacity and cost
  3. 3. 3 Outline 1. Motivation, objectives and contribution 2. Theory and methods 3. Results 4. Conclusions and future work
  4. 4. 4 Ionosphere monitoring in GBAS using DF measurements MOTIVATION Ionospheric delay [m] Ionosphere Time [s] Nominal Ionosphere (No ionospheric events) No biases Similar trends
  5. 5. 5 Ionosphere monitoring in GBAS using DF measurements MOTIVATION Ionospheric delay [m] Ionosphere Time [s] 1. Ionospheric spatial gradient
  6. 6. 6 Ionosphere monitoring in GBAS using DF measurements Ionospheric delay [m] MOTIVATION Time [s] 2. Ionospheric temporal gradient (ionospheric gradient stationary or not moving w/airplane) Converging trend during approach
  7. 7. 7 Ionosphere monitoring in GBAS using DF measurements Ionospheric delay [m] MOTIVATION Time [s] 3. Ionospheric moving gradient (ionospheric gradient moving w/airplane speed and direction)
  8. 8. 8 Ionosphere monitoring in GBAS using DF measurements OBJECTIVES OBJECTIVE 2 Threshold Ionospheric delay [m] Ionospheric Diff. delay [m] OBJECTIVE 1 Time [s] Time [s] Monitor ionospheric differential delay between Airborne and Ground
  9. 9. 9 Ionosphere monitoring in GBAS using DF measurements MOTIVATION, OBJECTIVES AND CONTRIBUTION MOTIVATION OBJECTIVES CONTRIBUTION All ionospheric gradients cannot be detected with single-frequency GNSS. The proposed ionospheric monitor estimates the ionospheric differential delay without moving to a whole Dual-Frequency GBAS concept.
  10. 10. 10 Outline 1. Motivation, objectives and contribution 2. Theory and methods 3. Results 4. Conclusions
  11. 11. 11 Ionosphere monitoring in GBAS using DF measurements Ionospheric delay [m] OBJECTIVE 1 Time [s]
  12. 12. 12 Ionosphere monitoring in GBAS using DF measurements THEORY OBJECTIVE 1 1.1. Single rx Estimate the ionospheric delay for a single receiver Geometry-free ionosphere preserving lin.comb. Frequency dependent
  13. 13. 13 Ionosphere monitoring in GBAS using DF measurements THEORY OBJECTIVE 1 1.1. Single rx Estimate the ionospheric delay for a single receiver Geometry-free ionosphere preserving lin.comb. Frequency dependent
  14. 14. 14 Ionosphere monitoring in GBAS using DF measurements THEORY OBJECTIVE 1 1.1. Single rx Estimate the ionospheric delay for a single receiver Geometry-free ionosphere-preserving lin.comb. Ionospheric delay* (*using GIM) (Phase-based approach) (Code-based approach) 1. Reduce code noise 2. Estimate biases
  15. 15. 15 Ionosphere monitoring in GBAS using DF measurements THEORY OBJECTIVE 1 1.1. Single rx LPF
  16. 16. 16 Ionosphere monitoring in GBAS using DF measurements THEORY OBJECTIVE 1 1.1. Single rx
  17. 17. 17 Ionosphere monitoring in GBAS using DF measurements THEORY OBJECTIVE 1 1.1. Single rx Sv IFB Rx IFB Sv IFB Rx IFB [1] Sardon et al, “Estimation of the transmitter and receiver differential biases and the ionospheric total electron content from global positioning system observations”
  18. 18. 18 Ionosphere monitoring in GBAS using DF measurements THEORY OBJECTIVE 1 1.1. Single rx
  19. 19. 19 Ionosphere monitoring in GBAS using DF measurements THEORY OBJECTIVE 1 1.1. Single rx Sv IFB Rx IFB Estimate the ionospheric delay for a single receiver Summary of the method
  20. 20. 20 Ionosphere monitoring in GBAS using DF measurements Ionospheric delay [m] OBJECTIVE 1 Time [s]
  21. 21. 21 Ionosphere monitoring in GBAS using DF measurements THEORY OBJECTIVE 1 Code-phase approach Phase-based approach Single receiver estimate Single receiver estimate Average over Ground station receiver estimates Average over Ground station receiver estimates Airborne Subsystem Airborne Subsystem AIRB Ground Subsystem Ground Subsystem BR01 BR02 BR03
  22. 22. 22 Ionosphere monitoring in GBAS using DF measurements Ionospheric delay [m] OBJECTIVE 1 Time [s]
  23. 23. 23 Ionosphere monitoring in GBAS using DF measurements Ionospheric delay [m] OBJECTIVE 2 Time [s]
  24. 24. 24 Ionosphere monitoring in GBAS using DF measurements THEORY OBJECTIVE 2 2.1. Threshold [2] “GBAS CAT II/III Development Baseline SARPs,
  25. 25. 25 Ionosphere monitoring in GBAS using DF measurements Ionospheric delay [m] OBJECTIVE 2 Time [s]
  26. 26. 26 Ionosphere monitoring in GBAS using DF measurements THEORY OBJECTIVE 2 Code-phase approach Phase-based approach
  27. 27. 27 Ionosphere monitoring in GBAS using DF measurements Ionospheric delay [m] OBJECTIVE 2 Time [s]
  28. 28. 28 Outline 1. Motivation, objectives and contribution 2. Theory and methods 3. Results 4. Conclusions and future work
  29. 29. 29 Ionosphere monitoring in GBAS using DF measurements RESULTS GROUND SUBSYSTEM AIRBORNE SUBSYSTEM GNSS RX Monitor performance 1. Smoothing 2. Elevation 3. Distance to airport 4. Cycle slips 5. User dynamics
  30. 30. 30 Ionosphere monitoring in GBAS using DF measurements RESULTS Code-based Monitor performance using different smoothing constant Residual noise: Caused by code noise Reduced with larger smoothing constants
  31. 31. 31 Ionosphere monitoring in GBAS using DF measurements RESULTS Phase-based monitor performance using different smoothing constant
  32. 32. 32 Ionosphere monitoring in GBAS using DF measurements RESULTS Monitor performance considering the user dynamics GNSS RX
  33. 33. 33 Ionosphere monitoring in GBAS using DF measurements RESULTS Monitor performance considering the user dynamics Phase-based approach (red) Jumps in the estimates. No line-of-sight during turns for a satellite with low elevation. Bias in the iono. estimates Code-based approach (blue) Large noise/MP in some epochs Problem in smoothing code-based estimate due to phase jumps Bad trend in the filter initialization Measure Waiting after losing phase measurements
  34. 34. 34 Outline 1. Motivation, objectives and contribution 2. Theory and methods 3. Results 4. Conclusions and future work
  35. 35. 35 Ionospheric delay [m] Ionosphere monitoring in GBAS using DF measurements Monitor ionospheric differential delay between Airborne and Ground subsystems Ionospheric Diff. delay [m] Time [s] Threshold Time [s]
  36. 36. 36 Ionosphere monitoring in GBAS using DF measurements CONCLUSIONS
  37. 37. 37 Ionosphere monitoring in GBAS using DF measurements FUTURE WORK
  38. 38. Ionosphere monitoring in GBAS using DF measurements Thank you for your attention Questions?

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