Abstract: The present invention provides a method and apparatus for determining a desired parameter of the motion of an object. In one embodiment, the device can be used to calculate the estimated carry distance of a golf shot. The golfer uses a keypad to enter the golf club and the units of measure for the output display. A Doppler radar system is employed to illuminate the golf ball. A reflected return signal is detected and difference pulses are generated, having a frequency which is proportional to the velocity of the ball. The difference pulses are processed by a microprocessor to determine if the radar beam has "locked" onto the ball. If so, the microprocessor calculates the carry distance by relating the average period of the difference pulses to a projected carry distance through empirically determined data. The carry distance can be displayed on the device, on a remote display, and/or can be stored in memory for later recall or transmission to an external computer.