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General Aviation Synthetic Vision Display

For the Quarterly Review of the NASA/FAA Joint UniversityProgram for Air Transportation Research

Friday, October 24th 2003

Douglas BurchMichael Braasch

Avionics Engineering Center

Ohio University, Athens

Project Sponsor: NASA/FAA Joint University Program

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Introduction

• On average one spatial disorientation accident occurred every eleven days from 1987 to 1996.

• VMC into IMC flight continues to be one of the two major areas producing the largest number of general aviation fatalities.

• General aviation instrumentation has undergone little change in the past 50 years.

• Major advancements have been made in the areas of inertial navigation and high accuracy GPS.

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VMC Versus IMC

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Overview• Motivation Behind General Aviation Synthetic

Vision Display (GASVD)

• Head-Up and Panel Mounted Displays

• General Aviation and Synthetic Vision

• System Architecture

• System Installation

• Flight Test Conclusions

• Recommendations

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Motivation Behind GASVD

• Provide Visual Cues in IMC

• Increase Situational Awareness in IMC

• Reduce Pilot Training and Currency Requirements for Flight in IMC

• Reduce Instrument Fixation During the Approach

• Cost-Effective Sensor Set for Tracking Aircraft State-Vector

• Cost Effective Synthetic Vision Display

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General Aviation & Synthetic Vision• Majority of Research has Focused on Commercial

and Military Applications

• General Aviation Technology is Handed Down from High Dollar Commercial and Military Research

• GA Synthetic Vision Research has Focused on Display Software and Human Factors

• Primary Cost of GA Synthetic Vision Display is the Sensors used to Drive the Display

• Focus Research on System Architecture and Display Placement and Take Advantage of Previous Research Regarding Software and Human Factors

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Spatial Disorientation

• Any conditions, which deprive the pilot of natural visual references to maintain orientation, such as clouds, fog, haze, darkness, or terrain/sky backgrounds with indistinct contrast (such as arctic whiteout or clear moonless skies over water)

Spatial disorientation is based on physics and basic aspects of human physiology affecting pilots of all experience levels.

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Radio Positioning

• Loran

• Global Navigation Satellite System (GLONASS)

• Global Positioning System (GPS)

The primary purpose of a radio positioning system is to approximate the current position of a user within a well-defined coordinate frame.

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Attitude Estimation

• Synthesized Attitude» Method 1: The Impact of GPS Velocity Based Flight

Control on Flight Instrumentation Architecture, Kornfeld, R., Hansman, R., J., Deyst, Report No. ICAT-99-5, June 1999

» Method 2: Conversations with Dr. Myron Kayton

• Inertial Measurement Unit» Gyroscopes & Accelerometers

General aviation requires a robust yet cost-effective method for estimating the attitude of the aircraft under low flight dynamics.

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Synthesized Attitude: Method Two

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Synthesized Roll Comparison

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Synthesized Roll Over Time, Low-Pass Filter (3-Point Moving Average)

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Synthetic Vision System Architecture

Research has focused on development of sensors and supporting architecture for tracking the aircraft state-vector

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Flight Test Aircraft

Piper Saratoga used to conduct flight tests of the General Aviation Synthetic Vision Display Developed at Ohio University.

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Sensors and Computer System

Prototype of sensor and data collection suite used to drive the Synthetic Vision Software.

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Projector Mounting

LCD projector used to display the rendering of the virtual world created by the Synthetic Vision Software.

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Combiner Material

Combiner material was placed in the test pilot’s field of view for use with the LCD projector creating the head-up display.

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Panel Mounted

Ideally the panel mounted display would be integrated into the instrument panel but was retrofitted just below the pilot’s field of view with minimal blockage of the instrumentation.

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Synthetic Vision Comparison

Two separate flight tests on UNI Runway 25. There is a slight altitude difference between the two approaches. The Synthetic Vision is still very compelling.

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Virtual Runway 25

Forward-looking virtual rendering of Runway 25 as provided to the pilot by the Synthetic Vision Software.

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Flight Test Results Head-Up Display

• Works Very Well in Close Proximity to the Runway

• Enables Pilot to Focus Attention on Forward Field of View

• Collimation of Display was not an Issue

• Severe Image Distortion that Improve on Approach

• Poor Performance in Normal Sunlight

• Difficult Installation

• Large Power Requirement

Pros: Cons:

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Flight Test Results Panel Display

• Works Well Regardless of Proximity to the Runway

• Allows Pilot to Visually Access Instrument Panel without Eye Strain

• Low Power Requirement

• Easy Installation

• Works Well in Most Lighting Conditions

• Difficult to Adjust to Size of Display vs. Real World Visual Cues

• Intense Light Source when Flying Close to Sunset

• Difficult to Maintain Altitude using Display

Pros: Cons:

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Recommendations

• Continue Research Using Panel Mounted Forward-Looking Display

• Combine Additional Visual Cues to Enhance Altitude Awareness

• Develop Combinational Displays to Include Bird’s-Eye-View

• Continue to Reduce the Size of the System and Power Requirements

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References• Kornfeld, R.P., Hansman, R.J., Deyst, J.J., The Impact of

GPS Velocity Based Flight Control on Flight Instrumentation Architecture. MIT International Center for Air Transportation, Cambridge, MA. Report No. ICAT-99-5, June 1999.

• Jennings, C., Alter, K.W., Barrows, A.K., Per Enge, J., D. Powell, 3-D Perspective Displays for Guidance and Traffic Awareness. Presented Sep 1999 at the ION GPS Conference, Nashville, TN.

• 1999 Nall Report, AOPA Air Safety Foundation, http://www.aopa.org

• Misra, P., P., Enge, Global Positioning System, Signals, Measurements, and Performance. Copyright © 2001 by Pratap Misra and Per Enge, ISBN:0-9709544-0-9

• Kayton, M., Private Communication with D. Burch, April 2003.

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Contact Information

Graduate Research Associate:

Douglas Burch

douglasburch@ieee.org

Principal Investigator:

Dr. Michael Braasch

mbraasch@oucsace.cs.ohiou.edu