Common-Phase Radar Coding for Fleet Interference Mitigation
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Solution Overview
Problem
Radar-to-radar interference in autonomous vehicle fleets is challenging due to the coherent nature of continuous wave interferers, leading to increased 'ghost' detections and complexity in conventional phase coded multiplexing techniques, which are not robust against interference from radars of the same type.
Innovation Solution
Implementing a common phase code for all radar transmitters within a vehicle, compensated on the receive side, to introduce incoherence between the vehicle's radar system and interferers, spreading interfering energy in the Doppler domain and reducing false detections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional phase coded multiplexing techniques are used, then radar systems can detect and classify objects, but interference from radars of the same type increases ghost detections and system complexity
Solution Approach 1:
The patent changes the phase code parameter from conventional approaches to a specific form where all transmit antennas use the same phase code. This parameter change introduces incoherence between interferers and the radar system, spreading interfering energy in the Doppler domain and reducing ghost detections while maintaining manageable system complexity
Solution Approach 2:
The patent segments the interference mitigation approach by applying phase compensation specifically in the Doppler domain through FFT processing. This segmentation allows the system to handle interference in a targeted manner without increasing overall system complexity
2Productivity
If a large number of radars are deployed in a fleet, then coverage and detection capability improve, but radar-to-radar interference increases ghost targets and false detections
Solution Approach 1:
By changing the phase code parameter to be identical across all transmit antennas, the system creates incoherence with external interferers. This allows a large number of radars to operate in the fleet simultaneously while the phase code structure spreads interfering energy, reducing ghost target generation even in dense deployments
Solution Approach 2:
The patent converts the harmful coherent interference from fleet radars into a beneficial spreading effect in the Doppler domain. The phase code structure transforms concentrated ghost target energy into distributed noise-like interference that is easier to filter and detect as false signals
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 mitigates intra-fleet interference by reducing ghost targets and maintaining computational efficiency, allowing for a large number of radars to operate effectively without significant additional complexity.
Implementation Method 1
Radar sensors are conventionally used in connection with detecting and classifying objects in an environment
Implementation Method 2
The FMCW radar introduces phase jumps from chirp to chirp that are common to all transmit antennas of a radar system on the vehicle
Implementation Method 3
The radar tensor includes power measurements generated by the radar sensor along different dimensions, such as Doppler, range, azimuth, and elevation
Data Source
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AI summary
A radar system comprises transmit antennas configured to transmit a radar signal and receive antennas that receive a radar return. The radar system further comprises circuitry configured to perform acts, the acts comprising generating a phase-shifted radar signal using a unique phase code that is commonly assigned to all transmitters included in the radar system. The acts further comprise transmitting the phase-shifted radar signal from transmit antennas and receiving a radar return at receive antennas. Additionally, the acts comprise, during signal processing, performing phase compensation by multiplying a radar signal received in the radar return by a phase compensation value that is commonly assigned to all receivers included in the radar system in order to remove the phase shift. The acts also comprise outputting an un-shifted processed radar signal.