A motion sensing method employing a first antenna (320, 690, 790, 890, 990, 1090, 1190, 1290, 1390, 1490, 1590, 1690, 1790) and a second antenna (310, 680, 780, 880, 980, 1080, 1180, 1280, 1380, 1480, 1580, 1680, 1780), the method comprising: monitoring for a first motion in a first region (220, 1020, 1120, 1220, 1320, 1420, 1520, 1620, 1720) using the first antenna (320, 690, 790, 890, 990, 1090, 1190, 1290, 1390, 1490, 1590, 1690, 1790) using a first motion detection parameter; when no first motion is sensed by the monitoring using the first antenna (320, 690, 790, 890, 990, 1090, 1190, 1290, 1390, 1490, 1590, 1690, 1790), monitoring for a second motion in a second region (210, 1010, 1110, 1210, 1310, 1410, 1510, 1610, 1710) using the second antenna (310, 680, 780, 880, 980, 1080, 1180, 1280, 1380, 1480, 1580, 1680, 1780) using a second motion detection parameter; when no second motion is sensed by monitoring using the second antenna (310, 680, 780, 880, 980, 1080, 1180, 1280, 1380, 1480, 1580, 1680, 1780), monitoring for a third motion in the first region (220, 1020, 1120, 1220, 1320, 1420, 1520, 1620, 1720) using the first antenna (320, 690, 790, 890, 990, 1090, 1190, 1290, 1390, 1490, 1590, 1690, 1790) using a third motion detection parameter; and when no third motion is sensed by monitoring using the first antenna (320, 690, 790, 890, 990, 1090, 1190, 1290, 1390, 1490, 1590, 1690, 1790) using the third motion detection parameter, designating a space, which encompasses the first region (220, 1020, 1120, 1220, 1320, 1420, 1520, 1620, 1720), as being unoccupied, wherein a beam width of the second antenna (310, 680, 780, 880, 980, 1080, 1180, 1280, 1380, 1480, 1580, 1680, 1780) is wider than a beam width of the first antenna (320, 690, 790, 890, 990, 1090, 1190, 1290, 1390, 1490, 1590, 1690, 1790), the first region (220, 1020, 1120, 1220, 1320, 1420, 1520, 1620, 1720) and the second region (210, 1010, 1110, 1210, 1310, 1410, 1510, 1610, 1710) overlap one another, the first motion detection parameter is different from the third motion detection parameter, and the second motion detection parameter is different from the third motion detection parameter. monitoring for a first motion in a first region (220, 1020, 1120, 1220, 1320, 1420, 1520, 1620, 1720) using the first antenna (320, 690, 790, 890, 990, 1090, 1190, 1290, 1390, 1490, 1590, 1690, 1790) using a first motion detection parameter; when no first motion is sensed by the monitoring using the first antenna (320, 690, 790, 890, 990, 1090, 1190, 1290, 1390, 1490, 1590, 1690, 1790), monitoring for a second motion in a second region (210, 1010, 1110, 1210, 1310, 1410, 1510, 1610, 1710) using the second antenna (310, 680, 780, 880, 980, 1080, 1180, 1280, 1380, 1480, 1580, 1680, 1780) using a second motion detection parameter; when no second motion is sensed by monitoring using the second antenna (310, 680, 780, 880, 980, 1080, 1180, 1280, 1380, 1480, 1580, 1680, 1780), monitoring for a third motion in the first region (220, 1020, 1120, 1220, 1320, 1420, 1520, 1620, 1720) using the first antenna (320, 690, 790, 890, 990, 1090, 1190, 1290, 1390, 1490, 1590, 1690, 1790) using a third motion detection parameter; and when no third motion is sensed by monitoring using the first antenna (320, 690, 790, 890, 990, 1090, 1190, 1290, 1390, 1490, 1590, 1690, 1790) using the third motion detection parameter, designating a space, which encompasses the first region (220, 1020, 1120, 1220, 1320, 1420, 1520, 1620, 1720), as being unoccupied, wherein a beam width of the second antenna (310, 680, 780, 880, 980, 1080, 1180, 1280, 1380, 1480, 1580, 1680, 1780) is wider than a beam width of the first antenna (320, 690, 790, 890, 990, 1090, 1190, 1290, 1390, 1490, 1590, 1690, 1790), the first region (220, 1020, 1120, 1220, 1320, 1420, 1520, 1620, 1720) and the second region (210, 1010, 1110, 1210, 1310, 1410, 1510, 1610, 1710) overlap one another, the first motion detection parameter is different from the third motion detection parameter, and the second motion detection parameter is different from the third motion detection parameter.