From my reading, partly between the lines... Some of your desired functions / intentions sound more full autonomous, like a robotic scout performing a survey flight path launched by you while remaining in a stationary position. Allowing the craft to perform the boundary loop flight path pretty much unassisted while you watch through the monitor (screen or FPV) and visually inspect fence line & sheep. More like you’re in a side passenger seat while you give attention to your livestock production and the drone intelligently flies the route.
I’d agree the CCVT on fence would provide a good consistent daily viewpoint, if you had enough cameras positioned to provide ample overlap over the 30 ac perimeter. Not sure if cost would be lower or higher, that would depend on hardware and quantity... my guess is higher. From someone that used horseback, 4x4 rigs & atv to inspect cattle, calfs & fence... in the brush, rolling hills, creeks, and tree’s shadows the visiual often needed to be almost next to fence line at times for a clear understanding; horseback was usually best option but most costly for time, care and maintence. Unlike a building structure or mowed terrain, the CCVT would probably miss a lot due to terrain and foliage.
I’m sure after 20 yrs, you’ve tried multiple options and atv’s... was brush too thick or uneven for atv? I can easily understand your desire to automate, it’s a chore to perform daily.
Personally, I don’t see the usefulness to walk & fly a drone through the brush or pasture, over & under tree lines... you’ll miss a lot on screen while visually watching the drone or watching where you’re walking... and your visual inspection would probably be better than video as you’re walking. Coverage of the 30ac boarder fence will be much slower than simply walking it when you add in the landings, battery swaps, getting flight ready for take off, and the normal array of issues that can occur with a drone on multiple battery mission.
Not sure what it’d entail, but I’d consider cleaning the fence line back to trail width, cutting back foliage at fence and ziping around border on an atv, hauling fence repair tools and livestock misc tools... livestock quickly adapt and learn it’s you on machinery.
A Drone might work if doing multiple sectional flight’s while jumping to each section via atv or truck.. this might be more productive than walking.
To accomplish a full robotic like autonomous flight, you’d need to spend the time walking the route while manually flying and recording desired route; develope and record a very close / multiple points and altitudes so there isn’t any route smoothing curves mixed into route. I haven’t used it, but you might check out Tuna’s autonomous program for the ST16... several on this site can give detailed insight on app.
After creating this mission, you probably could take a center zone field position and fly the route. Although I’d be surprised if you could consistently fly the route without issue due to branches & wind.
Another option, even more costly but easier autonomous flight to create. Utilize an IR Thermo camera and fly above tree top. Yuneec is bringing out a new higher 320 & 640 resolution Thermo camera... although I believe it’s for the H520 & Typhoon Plus platforms. This would give a dual camera perspective and provide dawn/dusk improved visibility before livestock began to move, easier for thermo to pickup, especially when above trees which challenge IR Thermo sensors.
The ‘ole manual walk is time consuming, but hard to beat.