Yep. The way you described it is a little hard to measure, you need frequency accuracy of a few parts per billion. You can do that with an OCXO or atomic standard, but that is bulky and power hungry. Instead if the transmitter also has a receiver it can monitor the signal reflection and it will see a shift of 2 Hz. Now it's comparing against itself and the 2 Hz shift is easily resolvable. The beat note is pretty low frequency. You can still resolve it but that can make for a slow measurement and be limited by 1/f noise in a simple homodyne receiver. Bump your transmit frequency up to 30 GHz and now the signal is at 200 Hz, and now you have a radar speed detector.