Abstract: The launch angle of an object in flight after being launched from a initial position, such as a golf ball struck by a golf club, is determined by measuring the velocity of the object using a sensor, such as a Doppler Radar transceiver, positioned, for example, at a known distance forward of the initial position along an expected straight aim line. The launch angle is calculated using a mathematical model, describing the relationship between the measured velocity as a function of elapsed time since launch and the geometrical relation between the sensor and the initial position. The aim angle of the object may be determined by performing independent launch angle calculations corresponding with velocity measurements from a plurality of sensors positioned, for example, in a line at a known distance forward of the initial position. The aim angle is obtainable from the ratio of the calculated launch angles.

Abstract: An apparatus for use in determining spin characteristics of an appropriately configured rotating object, such as a golf ball, includes a transmitter, a receiver, and a demodulator. The object is configured for reflecting radiation of at least a first frequency in a modulated fashion corresponding to at least one spin characteristic of the object. In this regard, an appropriately configured object may include at least one contrast area comprised of a material having different reflectivity than the rest of the object to electromagnetic radiation of at least the first frequency. The transmitter is positioned for transmitting electromagnetic radiation of at least the first frequency at the object. The receiver is positioned for receiving at least a portion of the modulated reflected radiation. The transmitter and receiver may comprise a single transceiver unit.