Evaluation of a Truth Reference System for High Dynamic Flight Testing

Evaluation of a Truth Evaluation of a Truth Reference System for High Reference System for High

Dynamic Flight TestingDynamic Flight Testing

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Truth Reference EvaluationTruth Reference Evaluation

Michael S. Braasch, Ph.D., P.E.Associate Professor of Electrical

EngineeringAvionics Engineering CenterOhio UniversityPh: 740-593-0105Email: braaschm@ohiou.edu

Avionics Engineering Center, Ohio University

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Expanded Flight TestingExpanded Flight Testing

High altitude (up to FL 390)

High speed (Vne = 440 kts)

High dynamics (fully aerobatic)

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Expanded Research Expanded Research OpportunitiesOpportunities

Space range safety test bedGPS acquisition and tracking under high

dynamicsGPS/INS testingFlight control researchSAR test bedYour R&D flight test

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AeroVodochody L-29 Delfin AeroVodochody L-29 Delfin SpecificationsSpecifications

Max Gross Weight: 7826 lbMax Crew Weight: 250 lb ea.G-limits: +8, -4Fuselage Tanks: 1000 L /

264 GWing Tanks: 300 L / 79 G

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Specifications (cont’d)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’

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First Flight TestFirst Flight Test

July 12, 2000Chillicothe, 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)

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Flight Test GoalFlight 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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ConclusionsConclusions 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