Radar Sensor Sub-Sampling for Lighting Control Power Reduction
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Solution Overview
Problem
Radar sensor systems in lighting control applications face high power consumption, particularly in standby modes, due to continuous operation of sensor systems, which contradicts the need for energy efficiency and compliance with stringent standby power consumption regulations.
Innovation Solution
Implementing a sub-sampling mode for radar sensors by setting the sampling frequency below two times the first Nyquist frequency, tailored to the state of the lighting device and detection area, to reduce power consumption while maintaining effective motion detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the radar sensor operates continuously at full sampling frequency to ensure reliable motion detection, then detection reliability is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic action by switching the radar sensor between active sampling phases and idle phases. During idle phases, the sensor remains powered but does not perform sampling operations, reducing power consumption while maintaining detection capability when needed. This is achieved through a controller that manages the sampling frequency dynamically based on system state.
Solution Approach 2:
The patent applies dynamics by making the sampling frequency adjustable rather than fixed. The controller dynamically modifies the sampling frequency based on the lighting device's operational state (standby vs. active), allowing the system to optimize between power consumption and detection reliability in real-time conditions.
2Use of energy by moving object
If the sampling frequency is reduced to lower power consumption, then energy efficiency is improved, but motion detection precision may deteriorate
Solution Approach 1:
The patent applies partial action by implementing sub-sampling where the sampling frequency is set below the traditional Nyquist rate (2× maximum Doppler frequency). Research shows that for presence detection applications, sampling at or even below the Nyquist frequency provides sufficient precision while significantly reducing power consumption compared to continuous full-rate sampling.
Solution Approach 2:
The patent changes the sampling frequency parameter dynamically based on operational requirements. By adjusting this critical parameter, the system achieves optimal balance between power consumption and detection precision for different states (standby vs. active operation), rather than using a fixed high sampling rate in all conditions.
3Adaptability or versatility
If sensor systems operate during standby mode to enable automatic lighting control, then control functionality is improved, but standby power consumption increases
Solution Approach 1:
The patent implements periodic action in standby mode by having the radar sensor perform sampling at reduced intervals rather than continuously. The controller manages the sampling frequency dynamically, allowing the sensor to remain in a low-power state while still periodically checking for motion events that would trigger lighting activation.
Solution Approach 2:
The system dynamically adjusts the radar sensor's operational state based on whether the lighting device is in standby or active mode. During standby, the sensor operates at reduced sampling frequency to minimize power consumption while maintaining the capability to detect motion and trigger lighting control functions when needed.
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 power consumption of radar sensors in lighting control systems, especially in standby modes, without degrading performance, and allows for adaptive sampling frequencies based on the lighting device's state and application scenario.
Implementation Method 1
Radar is a well-known detection system that uses radio waves to determine the distance, angle, or velocity of moving objects. A radar system works by radiating energy into space and monitoring the echo or reflected signals from the objects in the surround area
Implementation Method 2
If an object is moving either toward or away from the transmitter in the detection area, there is a corresponding change in the frequency of the reflected radio waves, caused by the Doppler effect
Implementation Method 3
A derived signal is generated by mixing the transmitted signal with the reflected signal received from the detection area
Implementation Method 4
the radar sensor sampling derived signals from the detection area at a sampling frequency
Data Source
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AI summary
Radar-based motion detection systems are widely used in smart home, smart building, and smart city area for automatic control. In this invention, methods, subsystem, systems, computer program are disclosed to achieve power reduction of a radar sensor by operating the radar sensor in a sub-sampling manner in an illumination control system. By combining the information related to the detection area and the state of a lighting device, the sampling frequency of a radar sensor is configured according the user scenario. A balance between power reduction and motion detection performance is achieved therefrom.