Abstract: The present invention provides a microwave vehicle detector which includes a transceiver for transmitting microwave energy into a desired target area and for receiving reflections of this microwave energy from vehicle movement in this target area. The transceiver includes first and second diodes for enabling the microwave vehicle detector to determine the direction of vehicle movement relative to the position of the microwave vehicle detector. In this regard, these diodes are balanced, such that a predetermined phase difference will be produced between the doppler shift signals generated by these diodes. This phase difference is analyzed by a microprocessor to determine the speed and direction of the vehicle being detected.

Abstract: A detection system is disclosed for a mobile storage system which causes the storage system to prevent movement of a storage element whenever a person is detected in an aisle between storage elements. The detection system uses a presence or motion detector for detecting the presence of a person in an open aisle without direct contact between the person and the detection system. Preferably, a radar transceiver operating in X-band is positioned to overlie each open aisle to detect presence of movement of a person in an open aisle, even slight movement such as breathing. The storage system in which the detection system is connected prevents any closing movement of a storage element adjacent an aisle in which a person is detected so as to avoid frightening the person in the aisle.

Abstract: A field disturbance monitor system which senses changes in a reflected signal caused by animate objects compared to inanimate objects in the same zone. The system employs a microprocessor which controls the system. A transmitter transmits a pulses microwave signal in response to a control signal from the microprocessor. A receiver receives a return signal which represents a reflection of the transmitted signal. A sample and hold circuit senses and holds the magnitude of the pulsed signal. Analog to digital conversion is obtained, whereby a ramp generator generates a ramp voltage which is compared with the magnitude of the received signal by a comparator. The microprocessor measures the time it takes the ramp voltage to rise to the magnitude of the detected signal. The microprocessor continuously computes a recursive short term average and compares this average value with a recursive long-term average. Deviations between the two time periods are the result of a disturbance within the monitoring field.