Using Copter in Guided mode with non-periodic heading updates


I have an application where I have to hover electrical power lines. In this situation, the compass is completely unusable. My strategy is to use computer vision to estimate the vehicle heading with respect to the cable and provide heading updates to the APM Copter position controller. However, during short periods of time (< 5 seconds) I may not be able to provide updates of the heading for various reasons (e.g. cable outside of the camera field of view). However, I would still like to use the Guided mode to control position (X/Y/Z) and stay over the cable. I need your experience to find answers to the following questions:

  • Is it the good forum to post this question?
  • For this short period of time without heading updates, do you expect a large drift on the heading?
  • Does this drift would be too significant and make the Guided mode unusable?
  • Is there any failsafe that I should take care to tolerate sporadic “compass lost”?

Thank you very much,