Patent NZ-578461-A (NZ)
Title: Electronic animal containment system with direction of approach determination
Inventor: BELCHER DONALD K
IPC: A01K15/04
Filed: 2008-01-17
Abstract: A direction-sensitive electronic animal containment system (100) comprises a wire loop (104) bounding a selected area (106), a containment signal generator in communication with the wire loop and a receiver unit determining a direction of approach based on at least one of the rising slope and the falling slope. The wire loop defines a safe zone, a correction zone, and an escape zone. The safe zone and the correction zone are located within the selected area. The escape zone is located outside the selected area. The containment signal generator generates a containment signal current in the wire loop. The containment signal current comprises a waveform having a rising slope and a falling slope with the absolute value of the rising slope not equal to the absolute value of the falling slope. The receiver unit corrects an animal when the direction of approach indicates the animal is entering the correction zone from the safe zone and the receiver unit allows the animal to pass without correction when the direction of approach indicates the animal is entering the correction zone from the escape zone. The receiver unit generates a received signal comprising a first pulse having a width and direction corresponding to one of the rising slope and the falling slope and a second pulse having a width and direction corresponding to the other of the rising slope and the falling slope. The direction of approach is determined from the width of the first pulse relative to the width of the second pulse. The wire loop (104) defines the boundary of the containment area 106. The dashed line represents the edge of the correction zone 108 within the containment area 106 and the dashed-and dotted line represents the edge of the warning zone 110 within the containment area 106. The area bounded by the warning zone 110 is the safe zone 112. The area outside of the wire loop represented by the stippling is the escape zone 116. Further disclosed is a direction-sensitive electronic animal containment system comprising a containment signal generator generating a containment signal having an asymmetric carrier current comprising a rising slope and a falling slope corresponding to a rate of change, a wire loop in communication with the containment signal generator, a receiver responsive to the containment signal and producing a received signal corresponding to the containment signal; a processing circuit in communication with the receiver and a stimulus delivery device in communication with the processing circuit. The absolute value of the rising slope is not equal to the absolute value of the falling slope. The wire loop bounds a containment area where an animal is to be contained and the wire loop carries the containment signal. The received signal comprises first and second pulse and each of the first and second pulses has a width and a direction derived from the rate of change of the asymmetric carrier current. The The processing circuit is responsive to the received signal and determines a direction of approach based on the width of at least a selected one of the first and second pulses having a selected direction. The processing circuit produces a stimulus control signal when the direction of approach indicates that the animal is approaching the wire loop from within the containment area and the processing circuit does not produce a stimulus control signal when the direction of approach indicates that the animal is approaching the wire loop from outside of the containment area. The stimulus delivery device produces a stimulus in response to the stimulus control signal and is adapted to deliver the stimulus to an animal.