Thank you @iampete for taking the time to read and digest - and respond to - my comments. I appreciate it.
It’s occurred to me that the mapping specific apps I’ve used with my commercial camera drones have the advantage of being written for a single task. ArduPilot, serving many purposes, is way more complicated.
I don’t know the history of the division of ArduPilot into individual programs for Copter, Plane, Rover, Sub, etc. - but I’m guessing that the issue is the same. It’s simply impossible for a single application to do everything well.
I don’t know what percentage of ArduPilot instances are used for mapping or agricultural missions - where similar functional needs exist. Maybe the functionality can be accomplished with a Mission Planner plug-in instead of mods to the firmware. If nothing less - I’d just like to help keeping the issues alive among the DEVs. If a goal of ArduPilot is widening it’s user base - better mapping support may be a way to achieve it.
Thinking through the power situation, I’m wondering if the “constant” power might be from an on-board battery connected to the carrier board’s Power-2 connector. I think this might be cleaner than using the flight controller’s USB connector.
Lastly, if I understand present functionality correctly, there’s still the issue of returning to the proper waypoint. As I understand it, current functionality is that the vehicle navigates back to the same waypoint it was when the mission was interrupted.
Mapping requires retuning to the last waypoint - not the next.
I think you may understand why - but for the sake of others reading this thread that are unfamiliar - there may be considerable distance between waypoints on a long mapping leg. Photos may be taken at distance or time intervals. The only way to ensure complete coverage is to return to the last waypoint. Going to the “next” waypoint will likely cause a gap in coverage.
This actually brings up a new problem of duplicate coverage. Returning to the last waypoint will cause all the actions (photos) be performed - which may be a repeat for some - if the mission was interrupted between waypoints separated by some distance.
There are multiple ways to address this - and no need to discuss it here. But I should say that the mapping apps I’ve used on commercial camera-drones all appear to address this - and photos are not duplicated when a battery failsafe triggers a RTH between waypoints.
Once again - thank you for your time and attention. I’ll report back when I try the “constant power” resume function.