FMCW Radar Signal Correction for Direct Transmission Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Radar devices face challenges in filtering out interfering frequency contributions from direct transmission and reflections on vehicle covers, which complicate the separation of actual object reflections in FMCW radar systems, leading to noise and reduced signal quality.
Innovation Solution
A device and method that process input signals by generating an oscillator signal, subtracting an amplified correction signal to produce a corrected input signal, mixing it to an intermediate frequency, amplifying, and using a low-pass filter to suppress predefined frequency ranges, thereby eliminating interfering components before mixing back to RF, enhancing signal quality and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FMCW radar systems are used to achieve time-linear measurement accuracy, then measurement precision is improved, but interfering contributions from direct transmission and cover reflections cannot be adequately filtered out
Solution Approach 1:
The signal processing is segmented into distinct frequency range treatments: a first frequency range (lower frequencies corresponding to direct transmission and cover reflections) is processed separately through the correcting unit with low-pass filter, while a second frequency range (higher frequencies corresponding to actual object reflections) is processed through the normal signal path. This segmentation allows selective suppression of interfering contributions while preserving actual reflection signals.
Solution Approach 2:
A correcting unit is introduced as an intermediary component between the downmixer and the analysis unit. This correcting unit contains a low-pass filter that selectively suppresses the first frequency range containing interfering contributions before the signal reaches the Fast Fourier Transform analysis unit, thereby mediating between the raw input signal and the final processed output.
2Reliability
If correcting units with low-pass filters are introduced to suppress interfering frequency ranges, then signal quality is improved, but device complexity increases
Solution Approach 1:
The correcting unit is merged into the existing signal processing chain between the downmixer and the Fast Fourier Transform unit. The low-pass filter in the correcting unit works in conjunction with the existing frequency modulation and mixing processes, combining multiple functions (frequency conversion, filtering, and interference suppression) into an integrated processing pathway rather than adding completely separate systems.
3Measurement precision
If the frequency range is divided into first and second frequency ranges, then interfering contributions are separated from actual reflections, but processing complexity increases
Solution Approach 1:
The signal processing pathway is made dynamic and adaptive: the correcting unit with the low-pass filter is selectively applied only to the first frequency range containing interfering contributions, while the second frequency range containing actual reflection signals bypasses the suppression. The system dynamically routes different frequency components through different processing paths based on their spectral characteristics.
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 effectively corrects interfering signals at the RF stage, reducing noise and enhancing the linearity and sensitivity of the output signal by separating interfering contributions from actual reflections, improving the overall quality of radar signals in FMCW systems.
Implementation Method 1
A downmixer mixes the corrected input signal downward to an intermediate frequency using the oscillator signal in order to generate a difference signal
Implementation Method 2
An upmixer mixes the correction-difference signal upward using the oscillator signal in order to generate a correction signal
Data Source
AI summary
A device for processing an input signal, including a local oscillator, designed to generate an oscillator signal; a subtracting unit, designed to subtract an amplified correction signal from the input signal in order to generate a corrected input signal; a downmixer, designed to mix the corrected input signal downward to an intermediate frequency using the oscillator signal in order to generate a difference signal; a first amplifier unit, designed to amplify the difference signal in order to generate and output an output signal; a correcting unit, designed to suppress a predefined frequency range of the output signal in order to generate a correction-difference signal; an upmixer, designed to mix the correction-difference signal upward using the oscillator signal in order to generate a correction signal; and a second amplifier unit, designed to amplify the correction signal in order to generate the amplified correction signal.