I have looked at tilt sensors and accelerometers, GPS modules and compasses. I am a little confused about whether I should use a tilt sensor to measure the latitude setting of the unit - related to the GPS position, or an accelerometer.
The only purpose I can see for the the accelerometer is for leveling the device, and I don't see what latitude or GPS have to do with that.
All this problem seems to call for is an equatorial plane set to the current latitude and aligned with true North, and a spirit level. If you want it to be completely self-leveling, self-aligning and self adjusting then it would be possible to automate all that by using GPS to obtain latitude, dual axis accelerometer to measure horizontal alignment and compass to measure alignment with North. And then some sort of servo mechanism to adjust the level, alignment and elevation.
Like all the best geek projects, I expect you would spend more time creating an automated setup than you would ever have spent doing it manually. That's not a reason not to do it, of course.