GPS failure-what happens to Radar display?

[N017RW]

In other words, apply the triangle of velocities or, if you prefer, ALLOW FOR DRIFT!

Yup. My (analog) E6-B FC still comes in handy!

 

[KevMo Photog]

How often do you anticipate losing GPS outdoors?
It's a hypothetical situation that you shouldn't encounter unless you fly into a canyon or under tree canopy or have an extremely rare hardware failure.

Def don't anticipate it happening but if it does good to know. Had it happen to me on a Yuneec Chroma over a year ago or so. I def learned something about the radar here too! Thx Kndl so much!

 

[DanMan32]

Radar doesn't only display direction but also distance. Recall that the further the AC is away from you, the further ring it places the AC on the radar. You need GPS to determine distance. Not only that but radar shows relative position to you which also needs GPS.
On a smartphone, at least with Go3, you can have the radar or the map showing on the left, not both. Only on a tablet is the radar static on the left, map or camera view on the right, depending which you have in your main view.

 

[KevMo Photog]

Radar doesn't only display direction but also distance. Recall that the further the AC is away from you, the further ring it places the AC on the radar. You need GPS to determine distance. Not only that but radar shows relative position to you which also needs GPS.
On a smartphone, at least with Go3, you can have the radar or the map showing on the left, not both. Only on a tablet is the radar static on the left, map or camera view on the right, depending which you have in your main view.

Very good info as well DanMan32! It's little things like this that we tend to overlook because the birds are so good now we get confident in the methods that we use as routine. So it's good to know all of these intricate systems for sure!

 

[DanMan32]

Here's a DJI training video for the P3 about the attitude indicators:

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[DanMan32]

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[DanMan32]

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[DanMan32]

Dang it, link won't work and can't paste strictly as text.

 

[DanMan32]

Search YouTube: DJI Safety Tips - How to Use the Attitude Indicator and Map in the DJI GO App

 

[davideo0]

How often do you anticipate losing GPS outdoors?
It's a hypothetical situation that you shouldn't encounter unless you fly into a canyon or under tree canopy or have an extremely rare hardware failure.

Hypothetical may be unlikely, but having spent 40 years as a professional pilot I suppose I’m used to training to be prepared for the “hypothetical” scenario.

This was the hypothetical situation I envisaged when I posed the original question :–

I am flying my drone at the extreme end of my VLOS, there is a moderate upper wind, possibly blowing away from the drone’s ideal course home. At that moment there is for some unaccountable reason a loss of GPS.

The drone quickly begins to drift downwind and out of VLOS. I cannot use the recommended procedure of right stick forward to see whether it flies left or right to apply an appropriate yaw correction to bring it home because I can no longer see it. Eyes not as good as they used to be, reactions a little slower.

Now if the Radar display is still working and I’m still within radio range – problem solved.

I agree, the likelihood of a complete GPS failure is small, but in aviation far more sophisticated systems go down, (see the accident reports).

Just call me a natural worry guts!

 

[shockwave199]

You can practice this scenario over and over again in the simulator. Up the wind speed, put the bird in atti and practice away at 2k' or more out. I often do that and try to fly back in, watching nothing but home point distance reading - very hard to do. The simulator is a great way to practice all sorts of scenarios safely.

 

[davideo0]

You can practice this scenario over and over again in the simulator. Up the wind speed, put the bird in atti and practice away at 2k' or more out. I often do that and try to fly back in, watching nothing but home point distance reading - very hard to do. The simulator is a great way to practice all sorts of scenarios safely.

Tks. Which particular simulator are you talking about?

 

[Jlbourne]

Tks. Which particular simulator are you talking about?

Quite possibly the dji go sim

 

[shockwave199]

Yes, the dji app simulator.

 

[OOO]

View attachment 78304
radar and map are separate , radar in lower left corner

You can switch between map and radar during flight. When map is open radar goes to right upper corner vice versa.

 

[OOO]

Right upper corner of map area.

 

[kndll]

Radar doesn't only display direction but also distance. Recall that the further the AC is away from you, the further ring it places the AC on the radar. You need GPS to determine distance. Not only that but radar shows relative position to you which also needs GPS.
On a smartphone, at least with Go3, you can have the radar or the map showing on the left, not both. Only on a tablet is the radar static on the left, map or camera view on the right, depending which you have in your main view.

Distance readings will need GPS but Radar will still work without GPS , Phantom will know what heading it is on , and all you have to do is turn 180 degrees and it will come back to you as you are standing somewhere on that heading , your actual home point / distance will not matter .

 

[davideo0]

Distance readings will need GPS but Radar will still work without GPS , Phantom will know what heading it is on , and all you have to do is turn 180 degrees and it will come back to you as you are standing somewhere on that heading , your actual home point / distance will not matter .

That's the conclusion I came to during the indoor experiment I carried out above. There was no distance information but as you say the heading and relative position could still be used to bring the aircraft back. But I guess you would need to have a GPS failure to be sure.
I suppose the fact that despite asking for information from anyone who has had a GPS failure to fill in the facts, no one has has come forward. So that must support the argument that a total GPS failure is remote. That, at least, is a pleasing conclusion.

 

[KevMo Photog]

Distance readings will need GPS but Radar will still work without GPS , Phantom will know what heading it is on , and all you have to do is turn 180 degrees and it will come back to you as you are standing somewhere on that heading , your actual home point / distance will not matter .

That is very cool to know kndl! I suppose if you turned your bird just after you had lost GPS though, then it would be hard to know if 180 was right back to you wouldn't it? But if we are on that line then it still should work right?

 

[kndll]

That is very cool to know kndl! I suppose if you turned your bird just after you had lost GPS though, then it would be hard to know if 180 was right back to you wouldn't it? But if we are on that line then it still should work right?

Yeah , I was thinking about a straight line flight only which is the wrong way to think , I think GPS failure means loss of Phantom unless very lucky circumstances , and don't even think about walking to where you think it should be , because it's going to drift !