Aeronautical Development Agency, Bangalore

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Contact Cdr. VS Renganathan : mailto:vsranga@ada.ernet.in

Overview

During mid 1999, it was necessary to setup a flight simulation facility for piloted evaluation of ski-jump launch and arrested recovery of a fighter aircraft from an aircraft carrier. The basic requirement of the simulation was to provide a realistic Image Generation System for ski-jump launch and recovery with 3 window Outside Window Imagery at minimum 1024x768 pixels resolution and 60 Hz refresh rate. It was decided to utilize this opportunity to investigate low cost hardware/software options to realize this objective.

Simulation Setup

Three PCs (dual PII, NT) with high-end graphics accelerator cards drive three SVGA video projectors onto three screens each with 45 horizontal FOV. The three visual workstations are driven by a flight model PC (dual PII, 10 Mbps Ethernet) using three non-blocking UDP sockets. Basic eye-point data (lat/lon/alt/h/p/r) along with other data for the HUD overlay are transmitted by the FMPC to each of the visual PCs at 80 Hz. The visual PCs running at 30-60 Hz (depending on scenery complexity) receive and use only the last packet. Pilot input is received from the cockpit through a Data Acquisition PC, by the FMPC, using a separate socket. Latency, although not measured until now, is well within 100 mSec. Pilots have so far not noticed any artifacts of transportation delay or distraction caused by lack of synchronization of the three windows, during preliminary evaluation. Latency is to be quantified soon.

Image Generator

FlightGear has been suitably adapted to meet the Image generation system requirements. Preliminary piloted evaluation was conducted recently with FlightGear version 0.6.1. The changes include:

Provision of three window display with each visual PC running the same executable and configured as left/center/right from the command line.

Provision of a moving aircraft carrier. The ship can be placed anywhere, with initial lat/lon/alt read off a text file. Update of lat/lon/h/p/r of the ship are received from the flight model PC every frame. Pitch, roll and heave are also simulated.

Provision of a fighter aircraft HUD overlay with 1:1 scale pitch ladder, velocity vector, energy marker and other reticles specifically for ski-jump launch and arrested recovery phases.

Future work

Beginning with the implementation of all the above features in the latest release of FlightGear, work on the following features are planned:

Re-configurable HUD with configuration read off config text file, using xml parser (suggested by Curtis).

Optical landing aid for carrier landing.

Provision of runway lights for night launch and recovery.

Ship wake, waves and sea state simulation.

Snapshots

ahuja2.jpg, ahuja6.jpg, beachview.jpg, landing1.jpg, landing2.jpg, landing5.jpg, view1.jpg

Curtis L. Olson