3 ms·
They could use rangefinding to limit the distance without dealing with precise timers.
by ryacko 7y ago
They could use rangefinding to limit the distance without dealing with precise timers.
- tinus_hn 7y agoHow does rangefinding work?
- ryacko 7y agoTrigonometric rangefinding using multiple sensors is simpler.
- foxyv 7y agoMost short distance rangefinders use an interferometer. You send a radar/laser/sound wave at a target and compare it against a reference. You measure the displacement in the phase angle of the beam bounced off the target to determine distance. You can get insane precision using short wavelengths. The most common long range rangefinders use nanosecond timers to measure the delay between a pulse and a response. At 100 meters, a laser beam will take 666ns to bounce off a target, 200 meters will take 1300ns etc... The precision of this method is a lot less because of confounding factors like the precision of your timing device, refraction, etc... Data will be encoded into the laser pulses similar to a GPS signal to reduce issues with cross talk between rangefinders and jamming. These measurements are confounded by the huge speed of light. A 1 nanosecond mis-timing will result in 0.3 meters loss of precision. A triangulating range finder (Usually a LIDAR) will further refine the above measurement by positioning sensors a distance apart to make medium distance sensing more accurate. This allows LIDAR scanners to increase their precision down into the millimeter range.