MIMO Radar Angle Estimation via Phase Relationship Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current MIMO radar systems face challenges in achieving precise angle estimation due to phase differences caused by relative movements and hardware complexity, particularly with time-division multiplex methods, which result in ambiguity in relative speed measurement.
Innovation Solution
A time-division multiplex method for MIMO radar that interleaves sequences of ramps with different transmission switching states, allowing for two-dimensional Fourier transformation of baseband signals to resolve ambiguity in relative speed estimation and improve angle resolution, while minimizing phase shifts from relative movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time-division multiplex method is used with different transmission switching states, then angle resolution is improved, but phase differences caused by relative movements increase making angle estimation more difficult
Solution Approach 1:
The patent applies preliminary action by calculating and storing expected phase relationships for multiple periodic relative speed values before angle estimation. The evaluation device pre-computes what the phase relationships should be for different speed scenarios, then compares these pre-established references against actual measurements to resolve the phase difference ambiguity caused by time-division multiplexing.
Solution Approach 2:
The patent changes parameters by examining phase relationships across multiple periodic relative speed values rather than assuming a single speed value. By analyzing how phase relationships vary with different speed parameters, the system can identify the correct speed value that matches the observed phase differences, thereby resolving the ambiguity introduced by time-division multiplexing.
2Measurement precision
If sequences of ramps with different transmission switching states are interleaved in time, then unambiguous relative speed estimation is achieved, but time interval between measurements is reduced
Solution Approach 1:
The patent applies periodic action by using sequences of ramps that repeat with different transmission switching states interleaved in time. Each sequence provides a periodic measurement opportunity, and by analyzing the phase relationships across these periodic measurements, the system can unambiguously determine relative speed while working within reduced time intervals between measurements.
3Adaptability or versatility
If multiple sequences with different time offsets are used, then measuring range for relative speed is increased, but hardware complexity remains high
Solution Approach 1:
The patent applies dimensionality change by moving from analyzing single-dimension signal amplitudes to analyzing phase relationships across multiple dimensions (different sequences, different time offsets, different periodic speed values). This multi-dimensional analysis approach enables extended measuring range for relative speed by exploiting the additional phase information without requiring additional hardware elements.
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 unambiguous estimation of relative speed and improved angle estimation with reduced hardware complexity, allowing for more precise location of radar targets despite shorter time intervals and larger measuring ranges.
Implementation Method 1
a transmitted signal which is frequency-modulated in the form of a ramp
Implementation Method 2
received signals are mixed down with the transmitted signal to form baseband signals
Implementation Method 3
Due to the Doppler effect, however, the frequency difference also contains a component that is caused by the relative speed of the object
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a MIMO-FMCW radar sensor and to a MIMO-time-division multiplexing method for locating a radar target (18), wherein a FMCW radar measurement is carried out using a transmission signal, of which the modulation patterns for different transmission switching states (m), which differ in the selection of antenna elements (12) used for transmitting, comprise time-interleaved sequences (22; 26; 32; 36) of ramps (24; 28; 34; 38); ambiguous values for the relative speed (v) of the radar target (18) are determined from a position (k, l) of a peak in a two-dimensional spectrum (56); phase relationships between spectral values of spectra (X) are checked for conformity with the phase relationships (a (v,m)) expected for a plurality of the determined values of the relative speed (v); based on said phase relationships, from the determined periodic values of the relative speed (v), an estimated value for the relative speed (v) of the radar target (18) is selected; and based on amplitudes and/or phase relationships between obtained base band signals (b), the angle of the radar target (18) is determined.