Hi!
I am currently doing a SITL simulation for a model similar to that of the iris example. I removed the gps plugin from the .sdf model since I don’t want to use gps navigation. I am able to arm but takeoff is denied:
pxh> WARN [commander] Takeoff denied! Please disarm and retry
INFO [tone_alarm] notify negative
INFO [commander] Armed by internal command
WARN [commander] Failsafe enabled: No manual control stick input
INFO [commander] Failsafe mode activated
INFO [tone_alarm] battery warning (fast)
INFO [commander] Disarmed by auto preflight disarming
INFO [commander] Failsafe mode deactivated
What other changes are necessary to be done so that navigation can occur without GPS?
That’s a quite interesting question! Few days ago I reached the same trouble… Maybe @LorenzMeier could answer to this question, because i didn’t find any possible answer…!!
Hi! thanks for the response.
So I understand that GPS is required for auto navigation. However, is it possible for the navigation algorithms to use the IMU measurements as a substitute of the GPS? In that way, no-GPS navigation could be performed since the IMU is providing position data.
So isn’t the navigation algorithm integrating the acceleration measurements from the IMU to obtain the position? I understood so…
In that case, if we provide the relevant initial conditions, couldn’t it be possible to use the IMU data as a gps-substitute?
Thanks @Jaeyoung-Lim i am quite interested in this topic too !! In my case im trying to fly a tricopter with altimeter and one IMU, i am a very beginner in this world… would be that possible??
@Xun@JuSevRo the position error of an unaided inertial navigation system (INS) is exponential and unbounded. It is only usable for more than a couple of seconds after initialization when using high grade IMUs. You can find a good read here: What is an Inertial Navigation System? · VectorNav
(The Pixhawks usually contains “consumer grade” IMUs)
Thanks for the reply @bresch.
Lets say I want to use a navigation grade IMU. And also an altimeter. Is there any way that those sensors provide enough information for navigation, provided I modify the control algorithms? Can I bypass the presence of GPS check for take off? What needs to be changed in the code to do this?