I think MEMS gyroscopes and accelerometers used in consumer drones should be just about good enough to measure orientation and acceleration, and those are cheap and easy to get.
You could integrate acceleration to get speed - the flight is short enough to make compounding errors easy to ignore.
I think thanks to drones and RC hobbyists, there's a generally nice body of knowledge on how to get good enough data from consumer hardware to keep things flying.
> You could integrate acceleration to get speed - the flight is short enough to make compounding errors easy to ignore.
‘Easy to ignore’ is not a term I would use here, especially given the motion environment of a rocket. It seems like it might be beginning to be borderline possible.
> You could integrate acceleration to get speed - the flight is short enough to make compounding errors easy to ignore.
False, given how noisy MEMS IMUs are, and the accuracy required. Even Ring Laser Gyros drift quickly.