GNSS Antenna Ground Plane with Segmented Slots for Multipath Rejection
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Solution Overview
Problem
GNSS antennas face challenges in suppressing multipath signals from nearby objects, which affect their performance and require designs that minimize reflections from both far-field and near-field objects, while maintaining high efficiency and reducing weight and dimensions.
Innovation Solution
The antenna system incorporates a ground plane with a nontransparent central area and a semitransparent peripheral area, featuring annular slots and vertical conducting elements to effectively suppress multipath signals by aligning wave paths and reducing fields in both the near and far zones, ensuring phase center stability and efficient signal reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an impedance choke ring ground plane is used to suppress both far-field and near-field multipath, then multipath rejection is improved, but the field in the top hemisphere horizon direction is reduced and the device dimensions and weight increase
Solution Approach 1:
The ground plane is divided into functional zones with different material properties and structures. The semitransparent area with annular slots and the peripheral area with vertical elements provide multipath suppression through geometric and material design rather than dense solid construction, reducing overall weight while maintaining effectiveness.
Solution Approach 2:
The ground plane structure transitions from solid conducting material to configurations with slots and vertical elements, changing the electromagnetic parameters (impedance, transparency, conductivity distribution) to achieve multipath suppression with reduced mass compared to traditional solid choke rings.
2Adaptability or versatility
If the antenna position relative to fixing elements changes, then adaptability is improved, but phase center stability deteriorates due to near-field multipath variations
Solution Approach 1:
The ground plane structure converts the harmful near-field multipath from fixing elements into a controlled electromagnetic environment. The semitransparent and peripheral areas are designed to maintain consistent phase characteristics even when tribraches or other fixing objects are present, transforming position variability into stable phase center performance.
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 solution significantly reduces the antenna's sensitivity to nearby object reflections, maintaining high efficiency and stability, with minimal distortion of the phase center and effective suppression of multipath signals in both near and far zones, even when the antenna position changes relative to fixing elements.
Implementation Method 1
an antenna receives not only the line-of-sight signal broadcast by a satellite but also signals reflected from the nearby objects (the so-called multipath reception)
Implementation Method 2
effectively suppress multipath signals by aligning wave paths and reducing fields in both the near and far zones
Implementation Method 3
rejection of multipath reception means that a field radiated by an antenna has to be low in the lower hemisphere area
Implementation Method 4
the antenna phase center should be independent of fitting elements (for example, tribraches) and antenna positions relative to the fixing elements
Data Source
AI summary
An antenna system includes an electromagnetic radiator assembled on a ground plane. The ground plane containing a nontransparent area in a center of the ground plane and a semitransparent area surrounding the nontransparent area. The nontransparent area is circular in shape. The semitransparent area is generally circular in shape and contains at least one slot. A plurality of vertical conducting elements are in proximity of a boundary between the nontransparent area and the semitransparent area on a bottom side of the ground plane. The vertical conducting elements are arranged in a circle around a center of the electromagnetic radiator.