Bergerie1 and John T
Gentlemen – thanks for the votes of confidence from you both – I find those comments exceptionally flattering … and particularly so when I consider who made them.
Of course simulation has come an exceptionally long way in a relatively short time – as the advancements in computer issues have advanced so have the applications of many specific uses of those computer systems. Here are some quotes from the latest attempt to standardize the technical issues regarding simulators and the testing that should be performed on each and every Flight Simulation Training Device (FSTD) with the tighter tolerances applicable to the higher levels of FSTD - Level C and Level D. The comments below are relative to motion, visual, and cockpit instrument responses. Latency timing in FSTDs is expressed in terms of milliseconds (ms) where 1 ms is equal to 1 one-thousandth of a second (0.001 second).
The transport delay test has become the primary method for determining the delay introduced into the FSTD due to the time taken for the computations through the FSTD controls, host, motion and visual computer modules. The transport delay test is not dependent upon flight test data, but may require avionics computer and instrument data from the data supplier for some cases
Relative response of the visual system, cockpit/flight deck instruments and initial motion system coupled closely to provide integrated sensory cues. Visual scene changes from steady state disturbance (i.e. the start of the scan of the first video field containing different information) should occur within the system dynamic response limit of 100 milliseconds (ms). Motion onset should also occur within the system dynamic response limit of 100 ms. While motion onset should occur before the start of the scan of the first video field containing different information, it needs to occur before the end of the scan of the same video field. The test to determine compliance with these requirements should include simultaneously recording the output from the pilot’s pitch, roll and yaw controllers, the output from the accelerometer attached to the motion system platform located at an acceptable location near the pilots’ seats, the output signal to the visual system display (including visual system analogue delays) and the output signal to the pilot’s attitude indicator or an equivalent test approved by the NAA.
FSTD response time — Motion. The FSTD response time for motion will be the elapsed time in ms between the pilot control input and the first discernable motion movement recorded by the accelerometers mounted on the motion platform. The latency for the motion system will be the FSTD response time (motion) minus the airplane response time in ms. This time is subject to the test tolerance.
FSTD response time — Visual system. The FSTD response time for visual system will be the elapsed time in ms between the pilot control input and the first discernable visual change measured as appropriate for the visual system. The latency for the visual system will be the FSTD response time (visual system) minus the airplane response time in ms. This time is subject to the test tolerance.
Note.— Visual system response time is measured to the beginning of the frame in which a change occurs.
FSTD response time — Cockpit instrument. The FSTD response time for cockpit instrument will be the elapsed time in ms between the pilot control input and the first discernable change measured as appropriate on the selected cockpit instrument. The latency for the cockpit instrument will be the FSTD response time (cockpit instrument) minus the airplane response time in ms. This time is subject to the test tolerance.
There are some simulators out there where, for whatever reason, they have latencies in some aspects of their operation down into the 20 - 30 ms range. Pretty impressive.
I'll have more to say later on other points raised in this thread - but for now, I've gotta run - cheers!