Vertically Offset Radar Sensors to Reduce Ground-Bounce Power Fading
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Solution Overview
Problem
Radar systems experience significant power fading due to ground bounce-induced destructive interference, which complicates target detection, especially at low grazing angles, and existing solutions to mitigate this issue increase system complexity and cost.
Innovation Solution
Implementing radar sensor units at different vertical positions on a vehicle to introduce a phase shift, ensuring one unit receives a constructive combination of signals while the other receives a destructive combination, thereby mitigating power fade without increasing hardware complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radar sensor units are positioned at the same vertical location, then the system structure is simple, but power fading occurs due to destructive interference from ground bounce signals
Solution Approach 1:
The patent applies vertical offset positioning to separate radar sensor units, transitioning from a single-plane configuration to a multi-dimensional spatial arrangement. This vertical separation introduces phase differences in ground bounce signals, converting a single-point vulnerability to power fading into a distributed system where units experience different interference patterns, thereby improving overall detection reliability.
Solution Approach 2:
The patent changes the spatial parameter (vertical position) of radar sensor units to alter the phase characteristics of received signals. By adjusting the vertical offset between units, the system transforms the signal interference pattern from consistently destructive to a mix of constructive and destructive interference, enabling more reliable target detection through signal combination.
2Reliability
If the vertical offset between radar sensor units is increased, then power fading is reduced through phase diversity, but the physical space required on the vehicle increases
Solution Approach 1:
The patent optimizes the vertical offset parameter to achieve sufficient phase diversity for power fading mitigation while constraining the physical space used. By carefully selecting the vertical separation distance, the system obtains the minimum necessary phase difference to convert destructive interference into constructive interference patterns, thereby achieving detection reliability improvement with minimal impact on vehicle mounting space.
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 power fading and blind spots by ensuring at least one radar sensor unit receives a constructive combination of direct and ground bounce signals, enhancing detection capabilities without additional complexity or cost.
Implementation Method 1
The different vertical positions introduce a phase shift to the received radar signal(s) so that when one radar sensor unit is receiving a destructive combination of signals, the other radar sensor unit is receiving a constructive combination of signals.
Implementation Method 2
Radar works by emitting high-frequency radio waves and measuring the reflection, or echo, of the waves from nearby objects. This can lead to strong multipath channels to objects of interest such as, for example, other vehicles on the road.
Implementation Method 3
These ground bounce channels can create destructive interference with the direct path signals causing considerable signal power decrease or power fading.
Implementation Method 4
The vertical offset provides one radar sensor unit with receipt of a constructive combination of one or more direct and ground bounce signals
Data Source
AI summary
Various technologies described herein pertain to systems and methods for mitigating radar signal power fading. In one embodiment, a diversity of radar sensor units having different vertical positions, or an offset, are provided. The different vertical positions introduce a phase shift to the received radar signal(s) so that when one radar sensor unit is receiving a destructive combination of signals, the other radar sensor unit is receiving a constructive combination of signals. This reduces the effect of signal power fade due to, among other things, ground bounce of radar signals destructively interfering with a radar sensor unit's ability to detect an object.