Radar Signal Segmentation for Velocity Ambiguity Resolution
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Solution Overview
Problem
Existing radar systems face challenges in accurately determining the distance and radial velocity of objects due to ambiguity in Doppler frequency measurements, especially when multiple reflectors are present, leading to masking issues and reduced unique velocity measurement ranges.
Innovation Solution
The method involves subdividing radar signal segments into at least two groups with different initial and/or final frequency values, allowing for separate evaluations and phase difference analysis to eliminate ambiguities and achieve unique radial velocity measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radar signals are modulated with short, rapid ramps and multiple reflectors are present, then the sampling frequency can be increased to improve distance measurement precision, but the Doppler frequency measurement range becomes ambiguous and multiple reflectors mask each other
Solution Approach 1:
The measurement cycle is divided into multiple measurement sections, each containing several ramps. The first FFT is performed within each measurement section to obtain distance information, while the second FFT is performed across measurement sections to obtain Doppler frequency information. This segmentation allows independent optimization of distance and velocity measurements, resolving the masking problem caused by multiple reflectors.
Solution Approach 2:
The patent extracts distance information and Doppler frequency information into separate processing stages. The first FFT extracts distance-related frequency components within each measurement section, while the second FFT extracts Doppler frequency components across measurement sections. This extraction separates the measurement of distance and velocity, eliminating the ambiguity in Doppler frequency measurement that occurs when multiple reflectors are present.
2Adaptability or versatility
If the unique velocity measurement range is increased to cover more radial velocities, then the sampling period for Doppler FFT must be extended, but this reduces the number of measurement sections available for distance determination
Solution Approach 1:
The patent dynamically adjusts the modulation parameters of different measurement sections. Each measurement section can have different ramp modulation characteristics, allowing the system to optimize the balance between velocity measurement range and distance measurement precision based on the specific application requirements. This dynamic parameter adjustment enables the system to adapt to different traffic conditions.
Solution Approach 2:
The patent changes the modulation parameters (such as ramp slope, frequency range) of different measurement sections to optimize both velocity measurement range and distance measurement precision. By varying these parameters across measurement sections, the system can simultaneously achieve wide velocity coverage and high distance resolution without the trade-off that would exist in a single uniform measurement configuration.
3Adaptability or versatility
If the Doppler frequency measurement is performed with extended sampling period to increase unique velocity range, then the measurement time increases, but real-time radar monitoring requires short measurement cycles
Solution Approach 1:
The measurement cycle is segmented into multiple measurement sections that can be processed in parallel. The second FFT operates across these segmented sections to achieve extended velocity measurement range, while each segment maintains sufficient data for accurate distance measurement. This segmentation allows the system to achieve both wide velocity coverage and short overall measurement cycle time.
Solution Approach 2:
The first FFT is performed preliminarily within each measurement section to obtain distance information before the second FFT is performed across sections for Doppler frequency analysis. This preliminary processing of distance information within each segment allows the system to prepare data structures that facilitate efficient subsequent Doppler analysis, reducing the overall measurement time while maintaining extended velocity measurement capability.
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 enables accurate and simultaneous distance and radial velocity determination by analyzing phase differences in the range Doppler matrix, significantly improving the unique measurable distance and velocity measurement capabilities.
Implementation Method 1
radar signals are transmitted from the measurement location and received again after reflection at the object
Implementation Method 2
received again after reflection at the object
Implementation Method 3
the transmitted radar signals are subdivided within a measurement cycle into numerous segments, in which they are changed in their frequency from an initial value to a final value
Implementation Method 4
a subsequent second evaluation of the signals for the frequency peaks of all segments of the measurement cycle is carried out to determine a Doppler frequency component as a measure of the radial velocity
Data Source
AI summary
The present invention relates to a method for determining distance (R) and radial velocity (v) of an object in relation to a measurement location, in which method radar signals are emitted and after reflection on the object are received again at the measurement location, wherein the emitted radar signals are subdivided within a measuring cycle into numerous segments (10) in which the frequency of the radar signals is gradually changed from an initial value (fA, fB) to the end value and each received reflected signal is subjected across one segment (10) to a first evaluation to detect frequency peaks and additionally a subsequent second evaluation of the signals for the frequency peaks of all segments (10) of the measuring cycle is carried out to determine a Doppler frequency component as a measure of the radial velocity (v). According to said method, an ambiguity in the determination of the relative velocity (v) is eliminated by subdividing the segments (10) into at least two groups (A, B), the initial value (fA, fB) of which and/or end value of the changing frequency are different, by subjecting the segments (11, 12) of each group (A, B) separately to the second evaluation and by determining a phase difference of the signals occurring during the second evaluation of the segments (11, 12) of each group (A, B) and corresponding to each other, thereby removing ambiguities in the determined velocity.