Patent ID: 8474172

Claim:
A RF system for preventing hunting accidents, which to achieve high resolution of said RF system, comprises: a RF transponder attached to a friendly target, which contains a millimeter-wavelength transmitter, which transmits a plain non-modulated RF signal via omnidirectional antenna, a RF interrogator mounted on a firearm, which contains a single-input millimeter-wavelength receiver comprising: a first and a second sharp-diagram receiving antennas having similar directional patterns angularly shifted in azimuth on equal angles about a sightline of said firearm in opposite directions, which receive RF signal sent by said RF transponder from the area to which sightline of said firearm is directed, a RF switch sequentially connecting outputs of said first and said second antennas to the input of said single-input millimeter-wavelength receiver, a microprocessor controlling said transmitter and receiver of said interrogator, which develops said request signal and processes said input RF response signal, a microprocessor controlling said transmitter and receiver of said transponder, which processes said input RF request signal and develops said response signal, an alert light mounted on sight of said firearm and activated by said microprocessor of said interrogator, an alert buzzer incorporated in said transponder that is activated by said microprocessor of said transponder, wherein: RF interrogator sequentially receives said plain non-modulated RF signal by means of sequentially-switched said first receiving antenna and said second receiving antenna, so, if direction to said friendly target is angularly misaligned with said sightline, input signal of said single-input millimeter-wavelength receiver becomes amplitude-modulated with a frequency of switching, wherein depth of said amplitude modulation is proportional to said misalignment that allows determining angular position of said friendly target about said sightline; and, when said friendly target is in dangerous sector of fire, said alert light and said alert buzzer are activated.