Evaluation of a Truth Reference System for High Dynamic Flight Testing

Avionics Engineering Center, Ohio University 2 Truth Reference Evaluation Michael S. Braasch, Ph.D., P.E. Associate Professor of Electrical Engineering Avionics Engineering Center Ohio University Ph:

Avionics Engineering Center, Ohio University 3 Expanded Flight Testing High altitude (up to FL 390) High speed (Vne = 440 kts) High dynamics (fully aerobatic)

Avionics Engineering Center, Ohio University 4 Expanded Research Opportunities Space range safety test bed GPS acquisition and tracking under high dynamics GPS/INS testing Flight control research SAR test bed Your R&D flight test

Avionics Engineering Center, Ohio University 5 AeroVodochody L-29 Delfin Specifications Max Gross Weight: 7826 lb Max Crew Weight: 250 lb ea. G-limits: +8, -4 Fuselage Tanks: 1000 L / 264 G Wing Tanks: 300 L / 79 G

Avionics Engineering Center, Ohio University 6 Specifications (cont’d) Takeoff speed: 100 kts Initial climb speed: 190 kts Vne: 440 kts (Mach 0.7) Cruise speed: 320 kts Fuel consumption: 150 gal/hr Length: 36’; Wingspan: 34’; Height: 10’

Avionics Engineering Center, Ohio University 7 First Flight Test July 12, 2000 Chillicothe, Ohio (RZT) Ashtech Z-12 (Ground and Air) Low Dynamics (static, taxi, take-off) Medium Dynamics (steep turns) High Dynamics (2g & 3g turns, aileron rolls)

Avionics Engineering Center, Ohio University 8 Flight Test Goal Evaluate traditional GPS-based truth reference system – Survey-type, dual-frequency GPS receivers – Ashtech PNAV software set for ‘aircraft’ dynamics (note: low-dynamic photogrammetry profiles are expected with this mode) – Limitation: no truth reference to check the truth reference

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Avionics Engineering Center, Ohio University 33 Conclusions Conventional truth reference system is not applicable in a high dynamic aircraft GPS receivers capable of high dynamics (such as the Ashtech G12) should be investigated Differential carrier-phase processing software should also be tuned for the dynamic environment Additional flight testing scheduled with G12’s in the next couple of months