Hello,
I’m trying to run a simple script for takeoff but since I don’t have a GPS unit, I get a ‘no 3D fix error’ when running on GUIDED mode (I can arm the motors in STABILIZE mode). I’ve tried disabing pre-arm checks (set to 0) but still get the same error.
Is there a way that I can take off on GUIDED mode without GPS?
I’m trying to test it indoors (plenty of space) and I’ve been through few ardupilot articles but seem to be very overwhelming at this point.
Thanks in advance!
Hi,
Yes, it is possible to fly guided without GPS, if you have some other way of measuring your velocity/position. This page about non-gps navigation describes the different options, e.g. an optical flow sensor, external tracking system, vio or an radio ranging system.
Hi,
Thanks for the reply. I am now looking to integrate Optical Flow sensors. Also, I’m looking to implement it in a lower light scenario and the Intel Intelisense camera seems to be ideal but it isn’t cheap. What’s a good recommendation for non-GPS nav in low-light environment?
Hi again,
Optical flow sensors are a quite easy and affordable solution for indoors flight, just be aware that the position estimate will be susceptible to drift and cannot be relied on in the long term.
To my knowledge is visual navigation in low light conditions still a somewhat open problem. One solution might be to instead use active sensors (lidars, structured light, time of flight, etc.), but they are often heavier and more expensive. I don’t know of any in this category that is so easy to set up as the optical flow sensors. Typically you can buy the sensor, but would have to implement the navigation algorithm yourself(or integrate an open source project).
The Intel T265 perhaps deserves to be mentioned spesifically. I have not tried it myself, but there are other projects on this forum that have. They(intel) claim that it will work in quite low lighting and they claim it will reduce drift by detecting loop closures.
If your budget is very limited I think the cheapest solution to low light conditions is to add a light source. I have not tried it myself, but LEDs on the drone might work if the floor have enough texture and you are flying at low enough altitude.
Note that I am no expert, so there might be other better solutions I have not mentioned here.