TDM MIMO Radar Angle Compensation for Accurate Velocity Estimation
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Solution Overview
Problem
MIMO radars face velocity ambiguity issues that degrade angular resolution and measurement accuracy, leading to inaccurate velocity estimation of targets, especially in scenarios where frequency modulation signals increase signal transmission cycles and require additional assumptions that may not hold in real-world conditions.
Innovation Solution
A method involving angle compensation using direction of arrival estimates and steering vectors to eliminate phase effects from echo signals, allowing for accurate velocity estimation without increasing signal transmission cycles or reducing angular resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TDM MIMO radar transmits frequency modulation signals of at least two different cycles to resolve velocity ambiguity, then velocity measurement accuracy is improved, but the signal transmitting cycle increases and target measurement update cycle increases
Solution Approach 1:
The patent performs angle estimation and angle compensation using receive array elements before velocity estimation. By pre-compensating the phase differences caused by angle effects on the M transmit signals, the system resolves velocity ambiguity within a single transmitting cycle without needing to transmit multiple different cycle signals, thus improving velocity measurement accuracy while avoiding increased transmission cycle
2Measurement precision
If TDM MIMO radar uses overlapped virtual array positions to resolve velocity ambiguity, then velocity measurement is improved, but the equivalent antenna array element length is sacrificed and angular resolution is reduced
Solution Approach 1:
The patent separates the processing of angle information and velocity information by using at least two receive array elements to estimate angle first, then compensating the M transmit signals based on this angle estimate. This segmentation allows independent optimization of angle estimation and velocity estimation, resolving velocity ambiguity without sacrificing the equivalent antenna array element length, thus maintaining both velocity measurement accuracy and angular resolution
3Ease of operation
If TDM MIMO radar performs velocity estimation in spectrum peak search manner or assumes targets gather around 0 degrees, then processing is simplified, but accurate velocity solution cannot be obtained in actual measurement scenarios
Solution Approach 1:
The patent uses at least two receive array elements to estimate the angle of target signals and feeds this angle information back to compensate the phase differences in the M transmit signals. This feedback mechanism creates a closed-loop system where angle estimation results are used to improve velocity estimation accuracy, enabling accurate velocity solution in actual measurement scenarios while maintaining reasonable processing complexity
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
Accurately estimates target velocity within the unambiguous range equivalent to that of a SIMO radar, improving measurement precision and maintaining angular resolution by compensating echo signals based on phase and angle information.
Implementation Method 1
A vehicle-mounted radar is an important component in an automated driving system. The vehicle-mounted radar may provide a vehicle with detection of a target object such as an obstacle or a moving object
Implementation Method 2
echo signals formed after transmit signals sent by a same transmit antenna are reflected by the first target
Implementation Method 3
a phase difference of the target is only a function of a velocity (Doppler frequency)
Data Source
AI summary
A velocity ambiguity resolving method and an echo signal processing apparatus are provided. The method includes: calculating, for first echo signals respectively received by at least two receive antennas in the N receive antennas, a first estimate of a direction of arrival formed by the at least two receive antennas and a first target, where the first echo signals are echo signals formed after transmit signals sent by a same transmit antenna in a time division transmit mode are reflected by the first target; separately performing, by using the first estimate, angle compensation on M second echo signals received by a first receive antenna, to obtain M first compensated echo signals; and performing velocity estimation based on at least two first compensated echo signals, to obtain a velocity of the first target.