Radar Signal Transmission with Phase-Coded MIMO for Speed and Angle
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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 systems with multiple transmit antennas.
Innovation Solution
A method involving the use of a first signal sent through one transmit antenna with a fixed phase and a second signal sent through multiple antennas using time or code division, combined with phase modulation, to achieve both large speed measurement range and high 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 divides the transmission antennas into two groups: a first antenna for sending the first signal (maintaining large speed measurement range) and second antennas for sending the second signal (providing angle resolution through phase modulation). This segmentation allows each antenna group to specialize in one function while the system as a whole achieves both requirements.
Solution Approach 2:
The patent introduces phase modulation as an additional dimension for signal differentiation. By modulating the phase of the second signal sent through multiple antennas, the system can distinguish between signals from different antennas without relying solely on time division, thereby maintaining speed measurement range while achieving angle resolution.
2Speed
If CDM/DDM/DDMA is used for simultaneous transmission of multiple antennas, then speed measurement range is maintained, but precise control of phase shifter is required limiting the number of antennas
Solution Approach 1:
The patent changes the modulation parameter from requiring precise continuous phase control to using discrete phase modulation steps. By using phase modulation with step 2πky/P where ky and P are integers, the system reduces the precision requirements on phase shifters while maintaining the ability to orthogonally transmit signals from multiple antennas.
3Productivity
If binary phase is used in DDM for two transmit antennas, then simultaneous transmission is achieved, but orthogonal transmission of more antennas cannot be implemented
Solution Approach 1:
The patent extends the static binary phase modulation to a more dynamic phase modulation scheme where the phase can take multiple discrete values determined by integers ky and P. This dynamic phase modulation allows the system to accommodate any number of transmit antennas by appropriately selecting different phase modulation parameters for each antenna.
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
The proposed method enables simultaneous enhancement of speed measurement range and angle resolution by optimizing signal transmission through multiple antennas, improving target detection accuracy and reducing the precision requirements on phase modulators.
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
measuring a distance, a speed, and an azimuth of an obstacle by detecting a reflected echo of the obstacle
Implementation Method 3
the vehicle-mounted radar may send a frequency modulated continuous wave (FMCW)
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.