Automotive Multistatic Radar Mode Switching for Interference Reduction

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Solution Overview

Problem

As the number of autonomous vehicles increases, so does cross-radar interference, particularly within fleets where radar systems are time-synchronized, leading to detrimental interference that affects the operation of radar systems and the vehicles they are part of.

Innovation Solution

Implementing passive multistatic radar processing in automotive radar systems, where one radar system operates in active mode while the other operates in passive mode, with the passive system receiving reflected signals from the active system to mitigate interference, and a server computing system or autonomous vehicles control the modes to minimize overlap.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If radar systems of multiple autonomous vehicles operate in active mode simultaneously, then each vehicle can independently detect objects, but cross-radar interference increases and detection reliability deteriorates

Engineering Contradiction:
Improvedetection reliabilityVSAvoidcross-radar interference
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent merges the radar systems of multiple autonomous vehicles into a coordinated multistatic radar network. Instead of operating independently, the vehicles share transmission and reception roles, with one vehicle transmitting radar signals while others receive reflected signals. This combination transforms individual monostatic radars into a collaborative multistatic system that eliminates interference through coordinated operation while maintaining enhanced detection capabilities across the fleet.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent inverts the traditional radar operation mode by switching between active and passive roles. Rather than all vehicles continuously transmitting radar signals in active mode, the system dynamically assigns one vehicle to transmit (active mode) while others receive (passive mode). This role inversion eliminates cross-interference because receiving vehicles do not transmit simultaneously, yet all vehicles contribute to object detection through their reception capabilities.

Inventive Principle:
Principle #13The other way round (Inversion)

2Object-generated harmful factors

If radar systems operate in passive mode to reduce interference, then cross-radar interference decreases, but the ability to actively illuminate targets is reduced

Engineering Contradiction:
Improvecross-radar interferenceVSAvoidtarget illumination capability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent combines the illumination capabilities of multiple vehicles by having them take turns transmitting radar signals in active mode. While one vehicle illuminates targets, others operate in passive reception mode. Over time, each vehicle gets opportunities to transmit, ensuring all targets in the fleet's operational area are illuminated by at least one vehicle. This merging of roles ensures continuous target illumination across the entire network without requiring simultaneous transmission from all vehicles.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements periodic switching between active and passive modes among fleet vehicles. Each vehicle cycles through transmission and reception roles at predetermined intervals or based on coordination signals from a central server. This periodic action ensures that target illumination is maintained across the fleet over time, as each vehicle periodically assumes the active transmission role to illuminate targets that may be in its detection sector.

Inventive Principle:
Principle #19Periodic action

3Object-generated harmful factors

If autonomous vehicles remain stationary to maintain radar coordination, then cross-radar interference is minimized, but operational flexibility is reduced

Engineering Contradiction:
Improvecross-radar interferenceVSAvoidoperational flexibility
Core Design Contradiction:
Object-generated harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic role assignment where vehicles can switch between active and passive modes based on their current positions, detection requirements, and coordination with other fleet members. Rather than fixed stationary positions, the system dynamically adjusts which vehicle transmits and which receive at any given moment. This dynamic coordination allows vehicles to move and change positions while maintaining radar interference minimization through real-time mode switching and role reassignment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent incorporates feedback mechanisms where vehicles communicate their positions, detection needs, and radar mode status to a central coordination server or directly to each other. Based on this feedback, the system dynamically adjusts active/passive assignments to maintain optimal interference levels while accommodating vehicle movements and operational changes. This feedback loop enables the fleet to adapt to changing conditions without sacrificing radar coordination.

Inventive Principle:
Principle #23Feedback

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 effectively reduces cross-radar interference, enhances radar perception, and improves tracking capabilities by leveraging cooperation between vehicles and localization techniques, allowing autonomous vehicles to operate more efficiently without purposeful repositioning.

Implementation Method 1

A first transmitter of the first radar system of the first autonomous vehicle and a second transmitter of the second radar system of the second autonomous vehicle can both transmit radar signals into a driving environment

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

a first receiver of the first radar system can receive, from the driving environment, a reflected radar signal responsive to the radar signal transmitted by the first transmitter

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4455714A1Opportunistic passive multistatic radar processing for automotive radar
Publication Date: 2024.10.30 GM CRUISE HOLDINGS LLC
  • EP4455714A1 patent drawingFigure 1
  • EP4455714A1 patent drawingFigure 2
  • EP4455714A1 patent drawingFigure 3

AI summary

Various technologies described herein pertain to opportunistically employing passive multistatic radar processing in automotive radar systems. A radar system of an autonomous vehicle is controlled to operate in an active mode during a first time period as the autonomous vehicle travels along a route. A transmitter and receiver of the radar system are enabled in the active mode. The radar system is controlled to operate in a passive mode during a second time period as the autonomous vehicle travels along the route. The transmitter is disabled and receiver is enabled in the passive mode. While in the passive mode, the receiver of the radar system receives a reflected radar signal responsive to a radar signal transmitted by a differing radar system of a differing autonomous vehicle. An object is detected based on the reflected radar signal and transmission information pertaining to the differing radar system of the differing autonomous vehicle.