Radar Velocity Measurement Using Phase Difference Interpolation
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Solution Overview
Problem
FMCW Radar systems face velocity ambiguity issues due to the limitation of sampling frequency range, leading to confusion in determining the true velocity of target objects.
Innovation Solution
A radar velocity measurement system and method that uses a radar module with a transmission antenna and a receive antenna to transmit electromagnetic waves formed of first and second sub-signals with different transmission times. The signal processor establishes even and odd number receive sequences from the echo signals, performs time domain to frequency domain conversion, and calculates the true reflection frequency by comparing the phase difference between the reflection signals to resolve the velocity ambiguity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If FMCW Radar uses a fixed sampling frequency range, then the radar system can operate continuously, but velocity ambiguity occurs when the radar echo frequency exceeds the sampling frequency range
Solution Approach 1:
The patent divides the continuous waveform into multiple sub-signals with different transmission times within one frame. This segmentation allows the radar to process different frequency components separately, resolving velocity ambiguity while maintaining continuous operation capability.
Solution Approach 2:
The patent implements periodic transmission of sub-signals with different transmission times within each frame. This periodic action creates distinct phase differences for different velocity ranges, enabling the system to determine true velocity without ambiguity while maintaining continuous radar operation.
2Device complexity
If the radar transmits electromagnetic waves at a single frequency, then the system structure is simple, but only object existence can be detected without distance and velocity information
Solution Approach 1:
The patent employs frequency modulation where the electromagnetic wave frequency changes over time according to a predetermined pattern. This dynamic frequency variation enables the radar to extract both distance and velocity information from the echo signal while maintaining relatively simple system structure compared to other radar types.
3Measurement precision
If the radar uses frequency modulation to transmit waves with changing frequency, then velocity information can be obtained, but velocity ambiguity occurs due to sampling frequency limitations
Solution Approach 1:
The patent introduces a time dimension by varying the transmission time of different sub-signals within a frame. This additional temporal dimension creates distinct phase relationships that allow the system to resolve velocity ambiguity and determine true velocity, transforming a one-dimensional frequency problem into a two-dimensional time-frequency problem.
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
The system effectively resolves velocity ambiguity by obtaining the true reflection frequency and calculating the true velocity of target objects, improving the accuracy of velocity measurement and reducing calculation complexity compared to existing methods.
Implementation Method 1
the receive antenna receiving an echo signal of the electromagnetic wave signal reflected by a target object
Implementation Method 2
the conversion unit carrying out a time domain to frequency domain conversion upon the even number receive sequence and the odd number receive sequence
Implementation Method 3
the compare calculation unit using the comparison model to carry out a comparison with a phase difference between the first reflection signal and the second reflection signal, thereby obtaining a true reflection frequency
Data Source
AI summary
The present invention provides a radar velocity measurement system, method, and radar device. The system includes a radar module and an electrically connected signal processor. The radar module includes a transmission antenna and a receive antenna. The signal processor includes a sequence unit, a conversion unit, and a compare calculation unit that are coupled with each other. The sequence unit establishes an even number receive sequence and an odd number receive sequence. The conversion unit carries out a time domain to frequency domain conversion upon the receive sequences to generate a first reflection signal and a second reflection signal, respectively. The compare calculation unit uses an interpolation method to compare the phase difference between the reflection signals with a comparison model to obtain a true velocity. Therefore, the present invention effectively prevents the velocity ambiguity issue of radar system.