Active Track- lost lock

PAW · May 31, 2019

This has happened to me 3x now (I have only used Active Track 3x). Using Trace Mode, my M2 will follow for a short distance (1 minute) and then lose lock. I keep my speed at 10-15mph with the drone following to the rear. I have seen tutorials where the drone followed at speeds between 25-30mph. All incidents occurred without other vehicles to confuse, no obstructions to the drone's vision, and no obstacle avoidance issues. The drone slowly drops back until it finally loses lock. The below shows the situation just a few frames prior to the loss of lock. Any ideas?

M2P w/SC (firmware current)
No wind, temp. 52 degrees, elevation 4900 ft, drone height between 95 and 150 feet.

Mossiback · May 31, 2019

If I were to hazard a guess, it would be going in and out of the shadows. Each time you go in one the "target" quickly changes causing a loss of lock and then is re-acquired when it leaves the shadow. By then the target is a dozen or more feet further away. Eventually, the target it too far away to maintain track.

On a side note, in the case pictured you are lucky that it lost track and stopped. Active Track will not follow the same course as the target (it will cut corners if the target turns). It looks like it was flying below the top of the tree on the left so it may have slipped sideways into it. YouTube is loaded with videos showing this type of accident.

brett8883 · Jun 1, 2019

PAW said:
This has happened to me 3x now (I have only used Active Track 3x). Using Trace Mode, my M2 will follow for a short distance (1 minute) and then lose lock. I keep my speed at 10-15mph with the drone following to the rear. I have seen tutorials where the drone followed at speeds between 25-30mph. All incidents occurred without other vehicles to confuse, no obstructions to the drone's vision, and no obstacle avoidance issues. The drone slowly drops back until it finally loses lock. The below shows the situation just a few frames prior to the loss of lock. Any ideas?

View attachment 74146

M2P w/SC (firmware current)
No wind, temp. 52 degrees, elevation 4900 ft, drone height between 95 and 150 feet.

I find it works much better at a lower altitude. Its just not able to recognize speed as well when that far from the subject.

I know its scary but in active track its using all of the OA sensors so sometimes you gotta just take a deep breath and let it do its thing. Get prop guards to use till you build some trust with it.

Donnie · Jun 1, 2019

Yep, a couple of times when I've explored active track I lost lock (hit the pause as soon as i realised so it would hover) anyway I put it down to it being near sunset and likely a shadows vs bright area contrasts situation.

PAW · Jun 1, 2019

It was early morning and I continually passed through areas of shadows... Thanks for the advice.

DanMan32 · Jun 1, 2019

You would think it would close the distance though, once it reaquires the target.

PAW · Jun 1, 2019

You would think...

Another thing I need to remember, as @Mossiback noted, since I was climbing a 7% grade (every 500 feet traveled horizontally increases altitude by 35 feet) I was rapidly eating into my 40-foot safety margin above the trees. Which was exacerbated by the treetops also climbing at a 7% rate.

Not good at math, but I think that means for every 500 feet I traveled my 40-foot above safety margin became roughly 30-foot below treetop level.

webvan · Jun 4, 2019

The M2 is supposed to go up and down in AT although it doesn't seem to work for everyone. It's possible the Smartphone needs to be equipped with a barometer (all iPhones have one these days).

Steady Eddie · Jun 4, 2019

I have found the same issue with Active Track with my Mavic Pro. Far from 100% reliable. So I started playing with Follow Me. I have a WiFi only iPad mini 4 and a Garmin Glo GPS receiver. This setup works flawlessly. The drone follows the GPS position of the mobile device, or rather the very accurate position reported by the Garmin Glo. The positioning is accurate to a meter or two. So good in fact that if I take two steps sideways, the drone does the same, and automatically compensates for changes in target elevation (actually I'm assuming the elevation thing because I have not yet put this aspect to the test). Have to say I've only tried it at walking speed, so not sure about tracking a faster moving vehicle.

webvan · Jun 4, 2019

AFAIK the MP doesn't follow up and down in "FollowMe". Litchi's FollowMe does PROVIDED you have a phone with a barometer AND you select the appropriate option (Mobile Device Elevation in Altitude Reference)

Steady Eddie · Jun 4, 2019

webvan said:
AFAIK the MP doesn't follow up and down in "FollowMe". Litchi's FollowMe does PROVIDED you have a phone with a barometer AND you select the appropriate option (Mobile Device Elevation in Altitude Reference)

But Litchi "Follow me" is only supported in the Android version, not in iOS unfortunately. I would think that the GPS elevation accuracy (not super accurate) would apply in Follow Me, whether Go4 or Litchi. I guess it all depends on the GPS accuracy of the mobile device being tracked.

webvan · Jun 4, 2019

Android only, yes.
GPS elevation can really be quite inaccurate and can "jump around" a lot, a lot of smoothing would have to be done to avoid accidents.

Steady Eddie · Jun 7, 2019

webvan said:
AFAIK the MP doesn't follow up and down in "FollowMe". Litchi's FollowMe does PROVIDED you have a phone with a barometer AND you select the appropriate option (Mobile Device Elevation in Altitude Reference)

You're right about GO4/Mavic Pro not changing altitude with terrain in Follow Me mode. Yesterday I had the drone follow me while walking up and down an incline with about 20 meters variation in elevation. No change in drone altitude going up or down the slope. Thanks.

tcope · Jun 7, 2019

webvan said:
AFAIK the MP doesn't follow up and down in "FollowMe". Litchi's FollowMe does PROVIDED you have a phone with a barometer AND you select the appropriate option (Mobile Device Elevation in Altitude Reference)

The Mavic changes altitude in AC mode by using the downward facing sensors.

Steady Eddie · Jun 7, 2019

AC mode? What's that?

webvan · Jun 7, 2019

Active Track ;-)
The Up/Down "depends" sometimes it works sometimes it doesn't (on the Air here) Depends on the height I suppose...

tcope · Jun 7, 2019

Steady Eddie said:
AC mode? What's that?

Sorry, hit the C instead of T. Active Track.

tcope · Jun 7, 2019

webvan said:
Active Track ;-)
The Up/Down "depends" sometimes it works

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sometimes it doesn't (on the Air here)

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Depends on the height I suppose...

Only when the downward sensors are working. I think the height limit is 33' (if memory serves correct).