[beachy]

Yep, the sensor would need to be buried/encased in a mat. The club needs to make contact with the mat realistically (i.e. like taking a divot on a real grass surface).

Most launch monitors today use high cameras or doppler radar. Neither of them really works without a ball. The difference between a good shot and a crap shot is a few millimetres. The technology can measure a bit of data from the club alone (club speed, angle of attack) but that's not enough to accurately extrapolate actual ball flight, since it's all about the quality of the contact of club on ball before ground.