Can anyone tell me why all the 'crash avoidance systems' fails to work in the dark on a P4Pro? I understood that the avoidance system was sonar, to me that shouldn't matter if its day or night. On the controller it gives me warnings that the system is not working, and the icon at the top is red with a "!" .
I haven't found anything online or in print about flying at night.
Now understand, Im talking about flying where I can see the P4P, its just the flight characteristics go crazy. Seems unstable, increased speed, jumpy.

Thanks for your input !

Hi Superdave,  I don't have a great answer for why a sonar system doesn't work well in the dark.  But there are other considerations for you to ponder when flying in the dark.
The VPS is "Visual Positioning System" pretty much only works at low altitude and requires good light and a ground surface with reasonable texture to function properly.   As an example, the VPS gets confused when you are hovering over a river because it sees the water moving and goes a bit kooky at times, can also get kooky if flying low over long grass that is moving in the breeze.  In the dark, your drone operates in the same way as if you have turned off the sensors.  It becomes much more sensitive to motion input, kind of like being in sport mode.  

Keep in mind that Sport mode isn't actually a boosted flight mode, sport mode is closer to being the native way that the bird can fly... NORMAL mode is throttled down in all ways, it flies smoother, can't go as fast, ascends and descends slower... all to make the bird easier to fly.  

Maybe you should spend some time flying (in an open field) in sport mode and even ATTI mode, to get a feel for what the bird is really capable of... rather than flying with the Normal (i.e. training wheels) mode.  This way you will be more adept at controlling the bird when flying in a situation (like low light, or indoors, or under a bridge, etc) where the sensors and GPS can't function properly.

Onward and Upward,
Matt

It happens because there isnt enough amient light, so It doesnt work well enough.

The sonar does work at night, but the sonar is only used to measure height above ground, that is why it can still do a controlled landing at night.

The obstacle avoidance uses stereo cameras with depth perception at the front and back which work with normal light, they can't see in the dark thus the obstacle avoidance is turned off at night.

I guess the side sensors could work at night since they use infra red light and have their own IR emitters, but they aren't much use without the front and rear visual cameras.

There is also a pair of stereo cameras under the aircraft with depth perceptions, again they can't see in the dark, these are used for positioning and when not working it has to use GPS positioning which is far less accurate and will jump around a bit, sometimes instant movements of several meters - never fly below head height at night, very dangerous!

It does not work at night. Turn them off or they will cause trouble. Get used to the terrain before flying. Remember every wires, trees and whatever. Fly with extreamly caution.

The vision system uses ultrasonic and image data to help the aircraft maintain the current position. Too dark or too bright will disable the VPS.  

Well I did some night flying tonight and landed in a tree. Can someone help me know where to start... I'm order to get my bird back taking beautiful photos and videos?  Won't let me send a pic to you guys

The Ultrasonic detection system is neither sonar (which actually is for underwater) nor radar components.  That is both good and bad news.  Good because if they were radial transmitted devices it would probably require further FCC licensing and open a whole new level of settings requirements for the device.  Bad, because imagine how cool it would be to have an actual radar detection option in which you could track other flying or nearby devices and calculate CPA (closest point of approach) and such.  But thats another $3000 story.  Maybe someday...  But since what the P4P does use has a combination of ultrasonic and light detection processing for its sensors, proper lighting is a necessity for its accuracy.  Maybe that's why DJI has the disclaimer "Never fly your P4P at night".  

Kuya Kano Posted at 2017-8-17 08:28
The Ultrasonic detection system is neither sonar (which actually is for underwater) nor radar components.  That is both good and bad news.  Good because if they were radial transmitted devices it would probably require further FCC licensing and open a whole new level of settings requirements for the device.  Bad, because imagine how cool it would be to have an actual radar detection option in which you could track other flying or nearby devices and calculate CPA (closest point of approach) and such.  But thats another $3000 story.  Maybe someday...  But since what the P4P does use has a combination of ultrasonic and light detection processing for its sensors, proper lighting is a necessity for its accuracy.  Maybe that's why DJI has the disclaimer "Never fly your P4P at night".

Ah !
Thank you for your reply! Makes sense.

Mabou2 Posted at 2017-8-16 12:20
Hi Superdave,  I don't have a great answer for why a sonar system doesn't work well in the dark.  But there are other considerations for you to ponder when flying in the dark.
The VPS is "Visual Positioning System" pretty much only works at low altitude and requires good light and a ground surface with reasonable texture to function properly.   As an example, the VPS gets confused when you are hovering over a river because it sees the water moving and goes a bit kooky at times, can also get kooky if flying low over long grass that is moving in the breeze.  In the dark, your drone operates in the same way as if you have turned off the sensors.  It becomes much more sensitive to motion input, kind of like being in sport mode.  

Awesome !
Thanks !!

BagoDJIoperator Posted at 2017-8-16 12:33
It happens because there isnt enough amient light, so It doesnt work well enough.

That's what I'm finding out!
Thanks!

Nigel_ Posted at 2017-8-16 12:55
The sonar does work at night, but the sonar is only used to measure height above ground, that is why it can still do a controlled landing at night.

The obstacle avoidance uses stereo cameras with depth perception at the front and back which work with normal light, they can't see in the dark thus the obstacle avoidance is turned off at night.

thank you, this will help.

fansa7dc5944 Posted at 2017-8-16 14:10
It does not work at night. Turn them off or they will cause trouble. Get used to the terrain before flying. Remember every wires, trees and whatever. Fly with extreamly caution.

Thanks, beginner trouble !

Dirty Bird Posted at 2017-8-16 15:08
The primary obstacle avoidance sensors are pairs of stereo optical cameras fore, aft, & below.  There are two ultrasonic sensors below but they are for ground proximity & maintaining altitude while flying low.  The side sensors are infrared, but these only work in Beginner & Tripod modes.  With the main OA sensors being optical, it stands to reason they can't function in low light.

Thanks, beginner troubles !

DJI Susan Posted at 2017-8-16 19:07
The vision system uses ultrasonic and image data to help the aircraft maintain the current position. Too dark or too bright will disable the VPS.

Thank you, this will help !

Superdave1 Posted at 2017-8-17 10:00
That's what I'm finding out!
Thanks!

no problem, I tried it during 4th of July weekend I kept giving me those areas.

Kuya Kano Posted at 2017-8-17 08:28
The Ultrasonic detection system is neither sonar (which actually is for underwater) nor radar components.  That is both good and bad news.  Good because if they were radial transmitted devices it would probably require further FCC licensing and open a whole new level of settings requirements for the device.  Bad, because imagine how cool it would be to have an actual radar detection option in which you could track other flying or nearby devices and calculate CPA (closest point of approach) and such.  But thats another $3000 story.  Maybe someday...  But since what the P4P does use has a combination of ultrasonic and light detection processing for its sensors, proper lighting is a necessity for its accuracy.  Maybe that's why DJI has the disclaimer "Never fly your P4P at night".

I believe flying at night is against FAA regulations too.  Could be wrong but I think it is.

Pvt Pilot '79 Posted at 2017-8-17 14:10
I believe flying at night is against FAA regulations too.  Could be wrong but I think it is.

Night flight is right. Haha

I guess it depends where you take off, and who sees it in the air.


I enjoy spending time in the country side, where no one cares,..

Besides, now I have the RGBY geks for my Lume Cube lighthouses, so it's a colorful new ball game.


RedHotPoker

Pvt Pilot '79 Posted at 2017-8-17 14:10
I believe flying at night is against FAA regulations too.  Could be wrong but I think it is.

You are absolutely right.  You are not allowed to fly in the dark.  You are allowed to fly for 30 minutes after official sunset (check the local weather) during the period called "Civil Twilight" if you have an FAA anti-collision light mounted to the drone.  It is relatively cheap and can be powered by a nine volt battery.  But once those 30 minutes have passed, you can only fly legally if you are night certified and have applied for a one evening permit with the FAA.

At least, them's thuh rools.

Pvt Pilot '79 Posted at 2017-8-17 14:10
I believe flying at night is against FAA regulations too.  Could be wrong but I think it is.

Actually, you're both "right and wrong".
FAA Part 107 Night Flight Waiver is the legal requirement for flying drones at night.  Fortunately, the P4P is already configured with the proper lighting for FAA night requirements, and to be specific is legal to fly until sunset.  The Part 107 waiver when applied, legalazies your night time flying.  
Here is the FAA link:
Part 107 Waiver for Night Flying

FAA Part 107 Night Flight Waiver Application

...Sorry, THIS is the direct link to the FAA legal application to fly at night. (Part 107 Waiver)
Pretty much the same rules as daytime flying for drones, just another tip in the FAA jar to keep having fun while the rest of the drones have to retire at sunset.  

Kuya Kano Posted at 2017-8-17 17:45
FAA Part 107 Night Flight Waiver Application

...Sorry, THIS is the direct link to the FAA legal application to fly at night. (Part 107 Waiver)

I should have known that

Kuya Kano Posted at 2017-8-17 08:28
The Ultrasonic detection system is neither sonar (which actually is for underwater) nor radar components.  That is both good and bad news.  Good because if they were radial transmitted devices it would probably require further FCC licensing and open a whole new level of settings requirements for the device.  Bad, because imagine how cool it would be to have an actual radar detection option in which you could track other flying or nearby devices and calculate CPA (closest point of approach) and such.  But thats another $3000 story.  Maybe someday...  But since what the P4P does use has a combination of ultrasonic and light detection processing for its sensors, proper lighting is a necessity for its accuracy.  Maybe that's why DJI has the disclaimer "Never fly your P4P at night".

You are correct, sonar is used in reference mostly to water, but did you know sonar was developed on another type of sonar called echolocate, which is what bats use. So if we stuck some bats inside the P4 we could achieve obstacle avoidance at night

fansb1fe1104 Posted at 2017-8-17 21:12
You are correct, sonar is used in reference mostly to water, but did you know sonar was developed on another type of sonar called echolocate, which is what bats use.

Good point, I never thought of that in regards to bats.  Having worked on ships for over 20 years, thats the first time I ever caught the connection of sonar being related above sea level.  Kudos to bats for teaching us how its done!

Dirty Bird Posted at 2017-8-16 15:08
The primary obstacle avoidance sensors are pairs of stereo optical cameras fore, aft, & below.  There are two ultrasonic sensors below but they are for ground proximity & maintaining altitude while flying low.  The side sensors are infrared, but these only work in Beginner & Tripod modes.  With the main OA sensors being optical, it stands to reason they can't function in low light.

Aren't there two sensors on the side? A round and oblong?? Why two?

BrianKushner Posted at 2017-8-17 22:36
Aren't there two sensors on the side? A round and oblong?? Why two?

one is the infrared light source, the other one is the receiver (sensor)

Antonio76 Posted at 2017-8-19 10:52
one is the infrared light source, the other one is the receiver (sensor)

Cool thanks. Wish it worked all the time.

Kuya Kano Posted at 2017-8-17 17:37
Actually, you're both "right and wrong".
FAA Part 107 Night Flight Waiver is the legal requirement for flying drones at night.  Fortunately, the P4P is already configured with the proper lighting for FAA night requirements, and to be specific is legal to fly until sunset.  The Part 107 waiver when applied, legalazies your night time flying.  
Here is the FAA link:

Well, the night flight waiver is ONLY for Part 107 pilots, and you need to have received a Night Flight Certification in order to qualify for the waiver.  Unless the rules are changing (again), the FAA will most likely not provide a night flight waiver unless the Part 107 and the Night Flight certification can be provided to them..

Mabou2 Posted at 2017-8-21 05:14
Well, the night flight waiver is ONLY for Part 107 pilots, and you need to have received a Night Flight Certification in order to qualify for the waiver.  Unless the rules are changing (again), the FAA will most likely not provide a night flight waiver unless the Part 107 and the Night Flight certification can be provided to them..

I'm applying for my 107 Waiver as we speak.  It is free to apply.  It is good for up to two years and they said I would have a response within 7 days.
Also I applied for three different conditions in the waiver at the same time:
1.  Night flight
2.  Extended maximum height to 1000m
3.  Extended distance beyond visual contact with drone on basis of electronic navigation mapping and visual contact via drone camera.
I'll let you know what the results are when they respond.

Kuya Kano Posted at 2017-8-21 07:54
I'm applying for my 107 Waiver as we speak.  It is free to apply.  It is good for up to two years and they said I would have a response within 7 days.
Also I applied for three different conditions in the waiver at the same time:
1.  Night flight

Interesting.  Well, the rules are changing faster than my bloomers.  heh.

Mabou2 Posted at 2017-8-21 08:31
Interesting.  Well, the rules are changing faster than my bloomers.  heh.

As fast as my mental image of what you look like as soon as you said you were bloomers.  hahaha.

Kuya Kano Posted at 2017-8-21 09:19
As fast as my mental image of what you look like as soon as you said you were bloomers.  hahaha.

Indeed... wouldn't be a pretty picture...  well, maybe?  No.  Not at all.

DJI Susan Posted at 2017-8-16 19:07
The vision system uses ultrasonic and image data to help the aircraft maintain the current position. Too dark or too bright will disable the VPS.

This might be the key: "ultrasonic and image data..."
Ultrasonic alone wouldn't explain failure in low light.

Not sure though if Susan is real anyway. Could be a robot.
She is promising beta updates by personal post in other threads, asking for account details and doesn't come back.

At least her Avatar is nice (Jessica Alba/Invisible Woman)
Major copyright infringement!

Eric13 Posted at 2017-8-21 13:14
This might be the key: "ultrasonic and image data..."
Ultrasonic alone wouldn't explain failure in low light.

The ultrasonic is available when the drone fly closely the ground. As for the beta firmware, please login your DJI account and refresh the firmware via DJI Assistant 2 later.
BTW, the PM may not work well sometimes, please reply me directly so that I can clear the reminder timely.