Object Detection Device with Dual-Interval Doppler and FM-CW Sampling
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Solution Overview
Problem
Existing detection devices struggle to accurately measure both the motion and distance of objects, particularly those with slow movements, due to the mismatch in sampling frequencies required for Doppler and FM-CW systems.
Innovation Solution
A detection device and method that employs first and second sampling times with different intervals for Doppler and FM-CW signals, allowing for simultaneous measurement of motion and distance by using a transmitter, receiver, mixer, and detector, with the detector performing first and second sampling at specific intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single sampling frequency is used for both Doppler and FM-CW systems, then the device complexity is reduced, but the measurement precision of motion and distance cannot be simultaneously optimized
Solution Approach 1:
The sampling process is segmented into two distinct operations: first sampling for motion detection at a first sampling frequency, and second sampling for distance measurement at a second sampling frequency. This segmentation allows each sampling operation to be optimized independently for its specific measurement purpose, resolving the contradiction between device complexity and measurement precision.
Solution Approach 2:
The sampling frequency is made dynamic rather than static. The detector automatically switches between first sampling and second sampling based on the measurement requirement (motion or distance), allowing the system to adapt the sampling frequency to the specific measurement task, thereby achieving high precision for both measurements without excessive complexity.
2Measurement precision
If the sampling interval is shortened to improve motion detection accuracy, then the measurement precision of motion is improved, but the productivity of distance measurement decreases
Solution Approach 1:
The sampling operations are segmented into motion-oriented first sampling and distance-oriented second sampling. The first sampling uses a shorter interval optimized for motion detection accuracy, while the second sampling uses a longer interval optimized for distance measurement efficiency. This segmentation resolves the contradiction by allowing each measurement type to use its own optimized sampling interval.
Solution Approach 2:
The detector performs periodic switching between first sampling and second sampling operations. By organizing the sampling into periodic alternating cycles, the system ensures that motion detection receives sufficient high-frequency sampling while distance measurement maintains adequate sampling rate, balancing accuracy and productivity through structured periodic action.
3Productivity
If the sampling interval is lengthened to improve productivity, then the productivity of detection is improved, but the measurement precision of motion decreases
Solution Approach 1:
The sampling system is segmented into two modes: first sampling with shorter intervals for motion detection and second sampling with longer intervals for distance measurement. This segmentation ensures that motion detection precision is maintained through adequate sampling frequency while overall detection productivity is improved through efficient distance measurement sampling.
Solution Approach 2:
The sampling interval is made dynamic, switching between shorter intervals during motion detection phases and longer intervals during distance measurement phases. This dynamic adjustment allows the system to optimize for precision when motion detection is needed and for productivity when distance measurement is the priority, resolving the contradiction between productivity and precision.
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
Enables precise measurement of both motion and distance of objects, even with slow movements, by optimizing sampling frequencies and methods for Doppler and FM-CW systems, enhancing detection accuracy and efficiency.
Implementation Method 1
a transmitter configured to transmit an electromagnetic wave or a sound wave as a transmission signal
Implementation Method 2
a receiver configured to receive a signal obtained by reflecting the transmission signal from an object
Implementation Method 3
a mixer configured to mix the transmission signal and the reception signal and output a mixed signal as an intermediate signal
Implementation Method 4
These techniques are disclosed in Patent Document 1 (Japanese Laid-Open Patent Publication No. 2019-49521)... using an electromagnetic wave or a sound wave... Doppler system
Implementation Method 5
using an electromagnetic wave or a sound wave... FM-CW (Frequency Modulated Continuous Wave) system
Data Source
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AI summary
A detection device includes a transmitter configured to transmit an electromagnetic wave or a sound wave as a transmission signal, a receiver configured to receive a signal obtained by reflecting the transmission signal from an object, as a reception signal, a mixer configured to mix the transmission signal and the reception signal and output a mixed signal as an intermediate signal, and a detector configured to detect a motion of the object and a distance to the object from the intermediate signal, wherein the detector performs first sampling of the intermediate signal at a first sampling time in a first time interval when detecting the motion of the object, and the detector performs second sampling at a second sampling time in a second time interval smaller than the first time interval, between adjacent first sampling times when detecting the distance to the object.