Microwave motion detectors utilizing multi-frequency ranging and target angle detection

1. A method of detecting a target within a predefined protected region with a microwave motion detector, comprising the steps of:

transmitting microwave frequency signals;

receiving the microwave frequency signals reflected by a target;

determining, from the received microwave frequency signals, a target distance;

determining, from the received microwave frequency signals, a target angle;

determining, from the target distance and the target angle, a target location; and

setting an alarm condition if the target location is within the predefined protected region; wherein:

the step of transmitting microwave frequency signals comprises transmitting a plurality of microwave frequency signals at different frequencies; and wherein

the step of determining, from the received microwave frequency signals, a target distance comprises:

generating from the received microwave signals intermediate frequency signal components, wherein each intermediate frequency signal component is representative of one of the received reflected microwave signals,

sampling the intermediate frequency signal components,

determining phase angles from the sampled intermediate frequency signal components,

determining a phase difference between the phase angles,

determining, from the phase difference, a corresponding target distance measurement.

2. The method of claim 1 wherein three or more microwave frequency signals are transmitted at different frequencies; and wherein:

the step of determining phase angles from the sampled intermediate frequency signal components comprises determining a first, second, and third phase angle from the sampled intermediate frequency signal components;

the step of determining a phase difference between the phase angles comprises determining a first phase difference between the second phase angle and the first phase angle, and determining a second phase difference between the third phase angle and the first phase angle; and

the step of determining, from the phase difference, a corresponding target distance measurement comprises: for each of the first and second phase differences, determining two corresponding distance measurements, wherein one distance measurement is a true distance measurement and the other distance measurement is an ambiguous distance measurement, and selecting an accurate distance measurement by matching the common true distance measurement of each phase difference.

3. The method of claim 1 wherein the intermediate frequency signal components are multiplexed on a single intermediate frequency signal, and wherein the step of sampling of the intermediate frequency signal components comprises the steps of:

collecting data samples of the intermediate frequency signal that corresponds to each of the three transmitted microwave frequency signals comprising the steps of:

enabling one of three data channels by selecting a switch to provide the intermediate frequency signal to the selected data channel, wherein the selected data channel corresponds to one of the three transmitted microwave frequency signals,

sampling and holding the intermediate frequency signal,

amplifying the selected intermediate frequency sample,

converting to digital format the amplified intermediate frequency sample, and

storing the digital intermediate frequency sample,

repeating for a predetermined number of times the step of collecting data samples to form three intermediate frequency data sets.

4. A method of detecting a target within a predefined protected region with a microwave motion detector, comprising the steps of:

transmitting microwave frequency signals;

receiving the microwave frequency signals reflected by a target;

determining, from the received microwave frequency signals, a target distance;

determining, from the received microwave frequency signals, a target angle;

determining, from the target distance and the target angle, a target location; and

setting an alarm condition if the target location is within the predefined protected region; further comprising the steps of:

detecting the location of the target for a plurality of location samples;

analyzing the plurality of location samples to determine if the target has transitioned from a first region to a second region, and

when the target has transitioned from a first region to a second region, initiating a predetermined action.

5. A method of detecting a target within a predefined protected region with a microwave motion detector, comprising the steps of:

transmitting microwave frequency signals;

receiving the microwave frequency signals reflected by a target;

determining, from the received microwave frequency signals, a target distance;

determining, from the received microwave frequency signals, a target angle;

determining, from the target distance and the target angle, a target location; and

setting an alarm condition if the target location is within the predefined protected region; further comprising the steps of setting a warning condition if the target location is not within the predefined protected region.

6. A microwave motion detector for detecting a target within a predefined protected region comprising:

a transmitter transmitting microwave frequency signals;

a receiving antenna, each receiving the microwave signals reflected by a target; and

processing circuitry adapted to:

determine, from the received microwave frequency signals, a target distance

determine, from the received microwave frequency signals, a target angle;

determine, from the target distance and the target angle, a target location and

set an alarm condition if the target location is within a predefined protected region; wherein:

the transmitter transmits a plurality of microwave frequency signals at different frequencies; and wherein

the processing circuitry determines, from the received microwave frequency signals, a target distance by being adapted to:

generate from the received microwave signals intermediate frequency signal components, wherein each intermediate frequency signal component is representative of one of the received reflected microwave signals,

sample the intermediate frequency signal components,

determine phase angles from the sampled intermediate frequency signal components,

determine a phase difference between the phase angles, and

determine, from the phase difference, a corresponding target distance measurement.

7. The microwave motion detector of claim 6 wherein three or more microwave frequency signals are transmitted at different frequencies; and wherein:

the processing circuitry determines the phase angles from the sampled intermediate frequency signal components by being adapted to determine a first, second, and third phase angle from the sampled intermediate frequency signal components;

the processing circuitry determines a phase difference between the phase angles by being adapted to determine a first phase difference between the second phase angle and the first phase angle, and determines a second phase difference between the third phase angle and the first phase angle; and

the processing circuitry determines, from the phase difference, a corresponding target distance measurement by being adapted to: for each of the first and second phase differences, determine two corresponding distance measurements, wherein one distance measurement is a true distance measurement and the other distance measurement is an ambiguous distance measurement, and select an accurate distance measurement by matching the common true distance measurement of each phase difference.

8. The microwave motion detector of claim 6 wherein the intermediate frequency signal components are multiplexed on a single intermediate frequency signal, and wherein the processing circuitry is adapted to sample the intermediate frequency signal components by:

collecting data samples of the intermediate frequency signal that corresponds to each of the three transmitted microwave frequency signals comprising by:

enabling one of three data channels by selecting a switch to provide the intermediate frequency signal to the selected data channel, wherein the selected data channel corresponds to one of the three transmitted microwave frequency signals,

sampling and holding the intermediate frequency signal,

amplifying the selected intermediate frequency sample,

converting to digital format the amplified intermediate frequency sample, and

storing the digital intermediate frequency sample,

repeating for a predetermined number of times the step of collecting data samples to form three intermediate frequency data sets.

9. A microwave motion detector for detecting a target within a predefined protected region comprising:

a transmitter transmitting microwave frequency signals;

a receiving antenna, each receiving the microwave signals reflected by a target; and

processing circuitry adapted to:

determine, from the received microwave frequency signals, a target distance

determine, from the received microwave frequency signals, a target angle;

determine, from the target distance and the target angle, a target location and

set an alarm condition if the target location is within a predefined protected region; wherein the processing circuitry is further adapted to:

detect the location of the target for a plurality of location samples;

analyze the plurality of location samples to determine if the target has transitioned from a first region to a second region, and

when the target has transitioned from a first region to a second region, initiate a predetermined action.

10. A microwave motion detector for detecting a target within a predefined protected region comprising:

a transmitter transmitting microwave frequency signals;

a receiving antenna, each receiving the microwave signals reflected by a target; and

processing circuitry adapted to:

determine, from the received microwave frequency signals, a target distance

determine, from the received microwave frequency signals, a target angle;

determine, from the target distance and the target angle, a target location and

set an alarm condition if the target location is within a predefined protected region; wherein the processing circuitry is further adapted to set a warning condition if the target location is not within the predefined protected region.