Radar Waveform Segmentation for Speed Range and Angle Resolution
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Solution Overview
Problem
Conventional radar systems face challenges in meeting the requirements for both speed measurement range and angle resolution due to limitations in orthogonal waveform design, particularly in MIMO radar configurations with multiple transmit antennas.
Innovation Solution
A method involving the transmission of a first signal through one antenna with a fixed phase and a second signal through multiple antennas using time or code division, combined with phase modulation, to enhance speed and angle resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TDM MIMO waveform is used to enlarge virtual antenna aperture, then angle resolution is improved, but maximum speed measurement range decreases
Solution Approach 1:
The patent segments the transmission signals into two distinct types: a first signal transmitted through one antenna without phase modulation to preserve speed measurement range, and a second signal transmitted through multiple antennas with phase modulation to achieve angle resolution. This segmentation allows each signal type to optimize for its specific measurement goal without compromising the other.
Solution Approach 2:
The patent introduces phase modulation as an additional dimension to differentiate between signals from different transmit antennas. By applying phase modulation with step 2πky/P to the second signal, the system creates orthogonal waveforms that enable angle resolution while maintaining the speed measurement capabilities of the unmodulated first signal.
2Measurement precision
If CDM or DDM is used for simultaneous transmission of multiple antennas, then angle resolution is improved, but precise control of phase shifter is required which limits the number of antennas
Solution Approach 1:
The patent changes the phase modulation parameter to a fixed step of 2πky/P, where P is an integer greater than 1 and ky is an integer greater than 0 and less than P. This parameterization allows for orthogonal waveform generation with relaxed phase control precision requirements, enabling the use of more transmit antennas without proportionally increasing system complexity.
3Measurement precision
If phase modulation with step 2πky/P is applied to second signal through m antennas, then orthogonal transmission is achieved, but signal processing complexity increases
Solution Approach 1:
The patent employs periodic phase modulation where the phase changes in discrete steps of 2πky/P across P slots. This periodic structure creates orthogonal waveforms that can be efficiently separated during reception using correlation techniques, reducing the overall processing complexity despite the modulation scheme.
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 simultaneous achievement of large speed measurement range and high angle resolution by optimizing the use of phase modulation and division methods, improving target detection accuracy.
Implementation Method 1
the vehicle-mounted radar may send a frequency modulated continuous wave (FMCW), and measure a distance, a speed, and an azimuth of an obstacle by detecting a reflected echo of the obstacle
Implementation Method 2
detecting a reflected echo of the obstacle
Implementation Method 3
phase modulation is performed, by using a step of 2πky/P, on a signal that is in the second signal and that is sent through each of the m transmit antennas
Data Source
AI summary
A radar signal transmitting method, a radar signal receiving method, and an apparatus applied to a radar apparatus are provided. The radar signal transmitting method includes: sending a first signal and a second signal in S slots, wherein a phase of the first signal remains unchanged in the S slots, and the first signal may be equivalent to a SIMO signal; and sending the second signal in at least one of a time division manner or a code division manner, wherein phase modulation is performed, by using a step of 2πky/P, on a signal that is in the second signal and that is sent through each of m transmit antennas, and the second signal is equivalent to a MIMO signal. When P=2, the MIMO signal is sent in a time division manner. When P>2, the MIMO signal is sent in a time division manner and a code division manner.