Signal Loss - Best Practices For Rapid Recovery

[cammot53]

I am new and a first time M2P drone pilot. Recieved my M2P last week and have been reading and viewing youtube clips a lot, to orient myself with the aircraft and preparing myself for first flight. I have so far flown three short flights of less than twenty minutes, in our backyard in beginner mode. The only one scare that I have encountered, was a RTH situation on landing !. I had originally taken off from our wooden deck, and was of the impression that the RTH would bring the drone to within a foot or so of its home position !. I was obviously dead wrong !, as the drone approached the landing area, it proceeded to go land a further distance of some twenty feet away from the deck !, and on a rough rocky slope !. I was unaware that I could have cancelled the RTH - and much less unaware that I could revert to a manual and controlled landing - I felt powerless !, unable to do anything but just watch the potential distruction of an expensive acquisition. For the first time I felt how dangerous these drones can be, if one is not fully learnt on all the ins and outs of drone flying. The drone did minor crash land in a haphazard matter, the props hit the the ground first, and the motors immediately cut off. On rescue, there was no visible damage, except for tiny clips on the props. My first shaky lesson ! - Learn and Practice Manual landings. I digress !

The purpose of this posting is “Reconnecting After a mid flight Signal Loss”, I appreciate that much has be posted on this subject, however, commentary is has been mostly related with prior firmware updates and not recent firmware updates on the M2P, and not necassary related to the M2P.

Is there a priority list of ‘Best Pratices for rapid Recovery on Signal Loss’ for immediate actions to take ?, including best settings to account for signal loss events. I’ve read things like, RTH home point is redefined on reconnect, and could be miles away !. I have also personally found that turning ‘on’ the RC is not always immediate and cumbersome, not quik and easy - several button presses etc, and can be slow.

Thanks

 

[Meta4]

I’ve read things like, RTH home point is redefined on reconnect, and could be miles away !.

A lot of things you might read in forums is of dubious accuracy.
The example you've given is a good example.
The home point is stored in the drone (which is how it can RTH if signal is lost).
You would have to power the drone off and restart it to get a new home point or manually reset the home point through the app.
It's never going to change by reconnecting.

 

[cammot53]

The home point is stored in the drone (which is how it can RTH if signal is lost).
You would have to power the drone off and restart it to get a new home point or manually reset the home point through the app.

Thanks - Logical !, puts to rest the dubious thought !

 

[EyeFlightDrone]

When I lose signal, I stand tall raising my arms and point the controller at the drone. It helps to regain the connection. Also raising the drone's altitude helps to regain the connection.

 

[Goof]

Read the manual, specifically the part where it tells you the RTH behaviour with respect to radius...

- If within 5m of the home point when RTH is triggered, the aircraft will land right where it is
- If within 20m but greater than 5m from the home point when RTH is triggered, it will fly straight towards the homepoint at a minimum altitude of 2m without rising to the preset altitude. Then it lands
- if greater than 20m from the homepoint when RTH is triggered it rises to the preset altitude, flies home and lands

These radii varied a bit on my old P4s, and I wouldn't expect any different on the new birds. A wayward flight course can be halted by flicking the TPS switch to any position other than the one it is currently in (may or may not work in beginner mode). Some flight modes will also respond to the pause button on the remote.

If it's landing due to low or critically low battery, you can usually still steer it down by applying maximum throttle, then steering with your roll / pitch controls (right stick).

 

[alekaras]

When I lose signal, I stand tall raising my arms and point the controller at the drone. It helps to regain the connection. Also raising the drone's altitude helps to regain the connection.

If you have signal loss it would be kinda difficult to raise the drone's altitude as there would be no way to tell the drone to climb. One poster (I don't remember if it was on this or another forum) mentioned that he sets the RTH altitude to a pretty significant height. He mentioned 500m, which I think is a bit extreme, but his point was that once RTH was initiated and the drone started climbing he would eventually regain signal and then take over manually. Probably before it even got anywhere close to 500m.

Of course there are downsides to this in that, if you initiate the RTH, the drone will climb to RTH altitude before RTHing, which in the above case would be 500m! So I think it is important that you practice bringing back the drone manually. I have never used the RTH function, because I prefer to have control of the drone throughout, and never had any issues bringing it back and landing it where I want to. It's really not that difficult to do it manually and allows you to adjust the speed and altitude, which can be very important when your battery is running low. I have seen many vids of users relying on the RTH to bring the drone back and coming short or cutting it really close where, if they had taken over and pushed up on the right stick would have gotten their drone back safely. Yes, increasing the speed will drain battery faster, but it will also bring the drone back faster than the battery drain.

 

[Goof]

Wouldn't recommend ever setting the RTH height to something ridiculous like that...

The reason for raising your arms is to try and help the control signal reach the drone. It can happen that you lose video signal before losing control signal, so even if you can't see anything on the screen, you can still sometimes get the drone to climb and throw the video signal back to the controller.

 

[alekaras]

Wouldn't recommend ever setting the RTH height to something ridiculous like that...

The reason for raising your arms is to try and help the control signal reach the drone. It can happen that you lose video signal before losing control signal, so even if you can't see anything on the screen, you can still sometimes get the drone to climb and throw the video signal back to the controller.

I wouldn't recommend it either, but if you are planning on taking over when signal gets re-established, you want to set it to a height that would allow you to eventually pick up the signal again. You can raise your arms about a meter, but that may not be enough.

Again, if you use the RTH function to actually do a RTH, I wouldn't recommend a very high RTH altitude. But if you are someone who always returns the drone manually, it would help with re-establishing the connection.

 

[ChopperLinc]

If you have signal loss it would be kinda difficult to raise the drone's altitude as there would be no way to tell the drone to climb.

Not necessarily true. Video and RC are on different transmissions. If you lose video, the drone will most likely still respond to RC initially. Raise altitude with RC and get video back.

 

[lmel2005]

A "signal loss" situation, usually is the ac-rc wireless disconnection.

If it lasts longer than a few seconds, rth mode is initiated.

During signal loss, you cannot control the drone, so you cannot change the altitude.

On the other hand, if the drone, raising to rth altitude, can establish an unobstructed line with the controller, signal may come back.

 

[Gienn1762]

I set mine to hover when it disconnects, why you may ask. One of the first time I had mine out I didn't know. That when it disconnects and goes into RTH it goes up to where you have it set at. I had it set at 30m and was flying about 30 feet high under a tree lime and it disconnected what do you think happen. I had no control and no time for me to cancel RTH it wasn't good

 

[lmel2005]

I set mine to hover when it disconnects, why you may ask. One of the first time I had mine out I didn't know. That when it disconnects and goes into RTH it goes up to where you have it set at. I had it set at 30m and was flying about 30 feet high under a tree lime and it disconnected what do you think happen. I had no control and no time for me to cancel RTH it wasn't good

It depends on where the drone usually is, during signal loss.
If you fly (for example) over water and experience a signal loss, drone will hover until critical battery level, and then it will "land" in the water. The same will happen, if it is above rocks, or just above trees.

 

[SteelFlyer]

For exactly all of the reasons stated in posts above, this is why it’s important to review the RTH settings as part of your pre-flight check every time you fly. You need to look at your surroundings and your flight plan and then set the RTH settings to fit those situations.

 

[SteveCA]

If you have signal loss it would be kinda difficult to raise the drone's altitude as there would be no way to tell the drone to climb. One poster (I don't remember if it was on this or another forum) mentioned that he sets the RTH altitude to a pretty significant height. He mentioned 500m, which I think is a bit extreme, but his point was that once RTH was initiated and the drone started climbing he would eventually regain signal and then take over manually. Probably before it even got anywhere close to 500m.

Of course there are downsides to this in that, if you initiate the RTH, the drone will climb to RTH altitude before RTHing, which in the above case would be 500m! So I think it is important that you practice bringing back the drone manually. I have never used the RTH function, because I prefer to have control of the drone throughout, and never had any issues bringing it back and landing it where I want to. It's really not that difficult to do it manually and allows you to adjust the speed and altitude, which can be very important when your battery is running low. I have seen many vids of users relying on the RTH to bring the drone back and coming short or cutting it really close where, if they had taken over and pushed up on the right stick would have gotten their drone back safely. Yes, increasing the speed will drain battery faster, but it will also bring the drone back faster than the battery drain.

I am the poster that sets RTH to 500m which is extreme when flying in relatively flat terrain where 100m would likely be sufficient. The thing to remember is that the pilot must manually stop the ascent as soon as signal is regained. This is easily done by pulling down on the left stick. At that point, assuming you haven’t cancelled RTH, the drone will fly straight home at that altitude. It will not continue to ascend. I personally hit the pause button to cancel RTH and regain manual control.

There are a number of situations where a sufficiently high RTH setting will be the only way you will ever see your drone again after losing signal. For example, I’ve read about folks who inadvertently flew behind a tall building, lost signal, and the drone was unable to return home due to the building being taller than the RTH setting. In that case, the drone flies towards home, encounters an obstacle and hovers until the battery is depleted and lands. The landing may be on a roof top, or worse, in traffic or on top of people.

When in comes to radio signal integrity, height and direct line of sight because of sufficient height, is your friend.

Many folks have commented that the high RTH setting is problematic in terms of battery usage, etc. While it certainly takes power to ascend 100 or 200 feet, it is measured in single digit %, which is nothing compared to the alternative. I have thoroughly tested battery usage in climbs and found that a 400 feet climb takes 6-8% battery. Flying back from 400 feet high takes very little battery, even from a mile away as the drone is dropping elevation while flying forward akin to gliding.

I set my RTH to the max because I fly in very mountainous terrain. It provides the best safety net for signal loss for my flying conditions. I would suggest that you survey your flying environments and set your RTH at least 50m above the tallest obstacles. That way you won’t have to join the exclusive club of pilots that have lost their expensive drones due to signal loss, which is 100% operator error. BTW, I’m in that exclusive club. I learned the hard way, but I learned well. YMMV

 

[EasyV]

You lose image transmission a lot of time prior to losing control signal. When you start losing image signal, that is a sign to bring your bird closer to you or in better unobstructed line of sight.

And yes, re orienting your antennna can sometimes get you better signal, sometimes...

 

[Meta4]

A lot of this discussion doesn't seem to take into account how Failsafe RTH works.
Earlier DJI drones would climb to RTH height and come home on loss of signal but later models have an additional step.
Failsafe RTH
The Forward Vision System allows the aircraft to create a real-time map of its flight route as it flies.
If the Home Point was successfully recorded and the compass is functioning normally, Failsafe RTH automatically activates after the remote control signal is lost for more than two seconds.
When Failsafe RTH is activated, the aircraft starts to retrace its original flight route home.
If the remote control signal is re-established within 60 seconds of Failsafe RTH being activated, the aircraft hovers at its present location for 10 seconds and waits for pilot commands.