The present invention pertains generally to target scoring devices and more particularly to a device for communicating an intercept score in a noisy environment. In the testing of both equipment and human skill, it is oftentimes desirable to automatically signal that a shell or projectile has come within the zone of the maximum detection range of a miss distance indicator of a target which is being fired upon. Penetration of the zone is commonly referred to as a score. This situation often occurs in ship gunnery exercises where a ship's crew wishes to determine the number of shells which have penetrated this zone.
Conventional automatic scoring systems have used various methods for detecting scores. A common system has used a doppler detector in which alternating current cycles amounting to heat frequency oscillations are generated by a miss distance indicator and are used to modulate a telemetry transmitter. The telemetry signal is, in turn, received by a receiving station on board the ship and demodulated so that the beat frequency oscillations can be detected. The oscillations generally range in a frequency from a few Hertz up to as much as 25 kiloHertz. The oscillations are then fed through a detection system which detects the presence of the oscillations above a certain threshold frequency. A counter is then used to count these oscillations above this threshold frequency to discriminate against noise and thereafter register a score.
In practice this system has presented various disadvantages and limitations in the presence of environmental and radio frequency noise. For example, in a case where the receiving antenna of a scoring indication unit is located proximate various radar transmitting antennas and other forms of RF interference, false score indications are prevalent. In this case and in the loss of the telemetry carrier, the automatic scoring device at the receiving station cannot effectively distinguish between the desired signal and the noise. The system, in general, has therefore not shown the reliability required to properly evaluate the functions being tested.