Hi,

We plan to put a GPS jammer on DJI M600 PRO and fly with ATTI mode for test purposes? I have some questions about safety issues.

1. First of all, is there anyone tried something like this ?
2. If RC signal is also lost due to signal interface, does RTH activate with wrong GPS Data and try to land an unsafe location, or does drone understand that there is problem about GPS and does not activate RTH.
3. When both GPS and RC signal is lost, what happens if both signal does not recovered ? I assume hovering at current position(assuming that no drift due to wind), but is there also a mode that lands the drone on current location by only controlling the attitude.
4. What is the frequency range and power of RC transmitter ?

Thanks.

You can find out about the frequency range and power of the RC transmitter through the product page on the DJI website under Specs. If the signal gets lost, it should provide a return to home with the aircraft.

For Specs:
http://www.dji.com/matrice600/info#specs

Change page 33 for Return to Home:

https://dl.djicdn.com/downloads/ ... _Manual_v1.0_EN.pdf

Regarding your other inquiry, we would not be able to evaluate the effect of this type of set up.

Dear Mark,

Thank you for the answer, i actually wonder what happens when GPS signal is lost in RTH, is it automatically enters into ATTI mode ? Also is it safe to fly in ATTI mode when GPS signal is jammed.

emresu Posted at 2017-9-19 00:45
Dear Mark,

Thank you for the answer, i actually wonder what happens when GPS signal is lost in RTH, is it automatically enters into ATTI mode ? Also is it safe to fly in ATTI mode when GPS signal is jammed.

It would enter into Atti Mode. Return to home would have the aircraft return to the last point documented as home.

So, in case of both GPS and RC signal lost, does drone tries to land current position by using other available sensors (accelerometer, gyroscope, etc.) ?
Is there an option to choose what to do(hover, land, flight termination) in DJI GO or DJI GS PRO for this case (both gps and rc signal lost) ?

emresu Posted at 2017-9-19 22:46
So, in case of both GPS and RC signal lost, does drone tries to land current position by using other available sensors (accelerometer, gyroscope, etc.) ?
Is there an option to choose what to do(hover, land, flight termination) in DJI GO or DJI GS PRO for this case (both gps and rc signal lost) ?

There would not be an option to choose what to do. If need be, you can always try to take control of the aircraft to land it as well once it is safe to do so.

It's pretty obvious what will happen in this scenario.
As soon as the GPS jammer is active, the craft will have no idea where it is and you will have to maintain control in ATTI and manually fly/land/takeoff.
Any automated function such as RTH will not have a valid current position to work with.

If you do this, you will need to manually pilot all aspects of the flight.

hello, do you know how to get the Raw gps data by text file or excel file from M600

DJI-Mark Posted at 2017-9-20 08:42
There would not be an option to choose what to do. If need be, you can always try to take control of the aircraft to land it as well once it is safe to do so.

I was trying to ask what happens when BOTH GPS and RC signal is lost. For the case i couldn't control over RC and also no RTH due to GPS loss. Does it tries to land automatically to current location.

DJI-Mark Posted at 2017-9-20 08:42
There would not be an option to choose what to do. If need be, you can always try to take control of the aircraft to land it as well once it is safe to do so.

Dear Mark,

I was trying to ask what happens when BOTH GPS and RC signal is lost. For the case i couldn't control over RC and also no RTH due to GPS loss. Does it tries to land automatically to current location.

emresu Posted at 2017-9-20 22:15
I was trying to ask what happens when BOTH GPS and RC signal is lost. For the case i couldn't control over RC and also no RTH due to GPS loss. Does it tries to land automatically to current location.

It would land on the location designated for Return to Home. The A 3 Controller also enforces a redundancy. Here is a link that discusses this point more: https://dl.djicdn.com/downloads/ ... _Manual_v1.0_EN.pdf

Go to page 28

DJI-Mark Posted at 2017-9-25 06:04
It would land on the location designated for Return to Home. The A 3 Controller also enforces a redundancy. Here is a link that discusses this point more: https://dl.djicdn.com/downloads/m600+pro/20170717/Matrice_600_Pro_User_Manual_v1.0_EN.pdf

Go to page 28

How can the aircraft return to home when there is no GPS signal ? At page 28 it says " Aircraft cannot return to home point when GPS signal is weak or unavailable"

emresu Posted at 2017-10-1 22:43
How can the aircraft return to home when there is no GPS signal ? At page 28 it says " Aircraft cannot return to home point when GPS signal is weak or unavailable"

You ready to be told to update the firmware again?   

I wish someone with actual knowledge of each and every system worked on the forum, your question could have been answered in one line, days ago.
My best guess is that it's programmed to wait at its current point and hover in hopes of the operator regaining control or regaining GPS. After it gets to a low battery state it probably tries to land in its current location using the imu and barometer, otherwise it probably just hovers and drifts due to no gps correction and when the batteries die it crashes.

I'm interested to hear if there's a difference in how it manages itself with RTK but loss of GPS satellites, still having the datalink connection to the ground station. It should have some idea of its location in 3D space so it should attempt to perform RTH in some way.

Dear ROBERM19,

Thanks for your answer that is much more meaningful than any DJI support answer   

I also assume similar scenarios to happen; however, hovering in a high wind situation may cause serious troubles for us so that i was trying to ask whether there is an option to land immediately when both GPS and RC signals are off. Losing both GPS and RC might be a very rare failure scenario but it is still disappointing that DJI has no answer for this situation. By the way, for drones that have no visual sensors, it is pretty easy to jam both RC and GPS signals simultaneously.