I've been considering building my own ground penetrating radar unit rather than pay outrageous rental fees and mind boggling full prices and I keep coming back to the same problem: time of flight is haaaard. My most recent thoughts on how to go about collecting that data would be to use 2 clocks/crystals that are offset from each other by fractions of a percent(one would be straight from a rubidium standard, and the other from a frequency multiplier). One would be in charge of timing the emitter and the other for timing the receiver.
This is the part where I make tons of assumptions about things I know nothing about, so correct me if I'm wrong.
The emitter is running at f1 and it emits a short pulse.
The receiver is running at f2 and collects data as fast as it can until the reflections dissipate.
The emitter pulses again
The receiver, due to the f1:f2 phase shift, is offset by a tiny amount and again collects data as fast as it can.
This cycle repeats until the collective phase offsets brings it back around, building the image . My thinking is that this shift, given the time to cycle around, could provide data that is functionally in the range hundreds of GHz, provided the target doesn't move(which at milliseconds per dataset, is functionally true).
Could this work?