Ranging Microwave Detector Sensitivity Adjustment
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Solution Overview
Problem
Microwave motion detectors are prone to false alarms due to small animals and insects, and suffer from decreased sensitivity beneath the sensor due to limited MW energy transmission and reception patterns, without adequate consideration of target location for reliable minimization of false alarms.
Innovation Solution
A ranging microwave system with multiple range bins and a sensitivity adjustment module that determines the optimal alarm threshold based on the estimated target range, dynamically adjusting pulse threshold levels, duration, and frequency to differentiate between human intruders and small animals or insects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microwave sensitivity is increased to detect small animals and insects, then detection capability improves, but false alarm rate increases
Solution Approach 1:
The detection space is segmented into multiple range bins (near, mid, far) based on distance from the detector. Each range bin has independently optimized sensitivity thresholds, allowing the system to apply different detection criteria to different spatial zones. This resolves the contradiction by enabling high sensitivity for human detection in far ranges while maintaining lower sensitivity in near ranges where small animals are more likely, thereby reducing false alarms while preserving detection capability.
2Stability of the object's composition
If uniform sensitivity is applied across all detection zones, then detection consistency is maintained, but sensitivity beneath the sensor deteriorates due to limited MW energy transmission
Solution Approach 1:
The system applies local quality by assigning different sensitivity characteristics to different spatial locations. The detection zone beneath the sensor (where MW energy transmission is limited) receives enhanced sensitivity weighting through the range bin methodology, allowing the system to compensate for the physical transmission limitations in that specific region while maintaining appropriate sensitivity in other zones. This resolves the contradiction by allowing location-specific optimization rather than uniform sensitivity.
3Measurement precision
If high sensitivity is used throughout the detection range, then human intruder detection improves, but false alarms from small animals increase
Solution Approach 1:
The system dynamically adjusts sensitivity thresholds based on the detected range of the target. By using the ranging microwave system to determine which range bin a detected object falls into, the system can dynamically select appropriate sensitivity levels: high sensitivity for far-range detections (where human intruders are more likely) and lower sensitivity for near-range detections (where small animals are more common). This dynamic adaptation resolves the contradiction by making sensitivity a variable parameter rather than a fixed value.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces false alarms by optimizing sensitivity settings for different target ranges, enhancing the detector's ability to accurately identify human intruders while minimizing false triggers from small animals and insects, and improving sensitivity for intruders near the detector.
Implementation Method 1
MW technology often operates on the principle of phase shift or Doppler effect. Unlike PIR, MW technology is an active technology. The MW detector transmits MW energy, which reflects off objects and returns to the MW detector. Moving objects result in a received signal that is frequency shifted from the original transmitted signal.
Implementation Method 2
The MW detector transmits MW energy, which reflects off objects and returns to the MW detector. The amplitude is a function of transmitted signal strength, target size, distance, and reflectivity.
Data Source
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AI summary
Embodiments of the present invention are directed to a method and system for use of ranging MW to decrease MW intrusion detector false alarms. A Doppler microwave system may be provided that is capable of detecting an object range and adjusting the sensitivity of an alarm stage of a MW detector to account for object size and range. Multiple range limited MW stages may be configured for different ranges to determine the general range of the moving object. Based on signal levels present on these MW stages, an approximate object range may be determined. The sensitivity of the MW alarm stage is then adjusted based on a MW alarm state sensitivity vs. object range function that is optimized to alarm on humans and ignore small animals and insects. The method and system may be used in detection systems incorporating a MW sensor.