Sunday, October 4, 2015

FPV Latency Measurement of GoPro 4 Silver & Quanum Complete FPV bundle

One really critical performance attribute of any FPV system is it's latency- how much time elapses between when the FPV camera on your remote vehicle captures a frame of video and when it appears on your FPV goggles or groundstation monitor. If this latency is too great, it'll be really hard to control your FPV vehicle since you are watching what happened in the past rather than immediate feedback.

There is an easy way to measure latency with your system. Place a stopwatch (or stopwatch app on your phone) in view of your FPV camera. Start the stopwatch. Then, take a picture of both the stopwatch and your FPV display. Subtract the FPV display time from the stopwatch display and you'll have your latency. It can be a little tricky to get everything lined up to get a good photo, especially with the el-cheapo FPV goggles I have.

Human reaction time is ~ 0.1 seconds or 100ms. Hopefully your measured latency is less than that!

I measured the latency of my FPV system:

Test #1: Phone stopwatch on the left, FPV goggles on the right
 Test#1: 26.10 - 26.03 = 0.07 seconds = 70 ms


Test #2: 27.03 - 26.96 = 0.06 seconds = 60 ms

I'm pretty happy with the "measured" latency of the system- it seems like a GoPro4 with a real time video output cable, and the Quanum FPV bundle yields a latency of 60-70 ms. 

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