PX4 looks like a good platform for this application. It seems likely that the extra horsepower would be useful if not necessary for dealing with the volume of data that could potentially be generated.
I've started setting up the build environment on my PC. I followed the instructions in the PX4 Quickstart Tutorial for Developers. The PX4 Toolchain build is running into errors, starting with:
Generating the romfs image...
Generating the romfs header...
/bin/sh: xxd: command not found
make: *** [/c/px4/px4_nxbuilder/build/
Looks like I'm not the only one seeing the build error above. There is a post on one of the blog pages about the same error. Looks like this may be related to Vim (the "vi" text editor for Windows). I had Vim installed on my system long before PX4.
I resolved all of the build problems, with some help. Thanks guys! See the blog page (pointer above) for details if you're also having problems.
I ordered the basic PX4FMU and IO modules from 3D Robotics. I'm going to start by turning an existing R/C airplane into a UAV. Forgot to mention -- I've been active in R/C aviation for many years. See wingsontheweb.com.