Quadrature Doppler Radar Feature Detection Under Clutter Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Doppler radar systems for detecting object features are susceptible to external clutter interference, resulting in relatively poor accuracy due to their susceptibility to noise and interference.
Innovation Solution
The system employs a probe signal transmitter that loads a digital intermediate frequency signal onto a carrier signal, and an echo signal receiver that performs down conversions on quadrature signals to extract object feature signals, using a signal processor to identify features, thereby improving accuracy by filtering out noise and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Doppler radar is used to detect object features, then the detection function is achieved, but the detection accuracy deteriorates due to external clutter interference
Solution Approach 1:
The patent introduces an intermediary signal processing system that includes a local oscillator generating a reference signal at the same frequency as the transmitted radar signal. This reference signal serves as a mediator to mix with the received echo signal, enabling frequency translation and extraction of Doppler shift information while rejecting clutter interference through coherent processing
Solution Approach 2:
The system performs preliminary signal processing by mixing the received echo signal with a locally generated reference signal before further processing. This preliminary action of coherent mixing prepares the signal for subsequent filtering and analysis, enabling accurate extraction of object features while suppressing clutter
2Measurement precision
If simple threshold judgment circuit is used for signal processing, then the device complexity is reduced, but the detection accuracy deteriorates
Solution Approach 1:
The patent replaces simple mechanical threshold judgment circuits with an electronic signal processing system that uses mixing, filtering, and digital processing. This substitution enables more accurate detection of object features through coherent processing while maintaining practical device complexity through integrated circuit implementation
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 enhances the detection accuracy by filtering out low-frequency and direct-current interference, allowing for the reliable detection of features such as respiratory and heartbeat information, and moving speed, even in the presence of clutter.
Implementation Method 1
a probe signal transmitter (1) configured to load a digital intermediate frequency signal onto a carrier signal, and to transmit a loaded signal outwards
Implementation Method 2
an echo signal receiver (2) configured to receive an echo signal, and to extract an object feature signal by performing respective down conversions on a quadrature signal of the carrier signal and a quadrature signal of the digital intermediate frequency signal
Implementation Method 3
Existing technology for detecting an active object is generally implemented with a Doppler radar
Implementation Method 4
the object features can be obtained by detecting the frequency of the amplified low frequency signal
Data Source
AI summary
An apparatus for detecting object features can include: a probe signal transmitter configured to load a digital intermediate frequency signal onto a carrier signal, and to transmit a loaded signal outwards; an echo signal receiver configured to receive an echo signal, and to extract an object feature signal by performing respective down conversions on a quadrature signal of the carrier signal and a quadrature signal of the digital intermediate frequency signal; and a signal processor configured to identify object features according to the object feature signal.