HCIS Ground Plane Multipath Suppression for GNSS
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Solution Overview
Problem
Global navigation satellite systems (GNSS) face significant errors in position determination due to multipath reception, where antennas receive direct and reflected satellite signals, leading to inaccuracies in time delay and carrier phase measurements.
Innovation Solution
An antenna system featuring a high capacitive impedance surface (HCIS) ground plane and an antenna positioned above it, with specific design parameters to maximize sensitivity to low-elevated satellites while minimizing multipath signal reception, achieved by optimizing the down/up ratio and antenna pattern levels at defined elevation angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional choke-ring antennas are used, then multipath reception is suppressed to some extent, but positioning accuracy is limited and sensitivity to low-elevated satellites is reduced
Solution Approach 1:
The patent changes the electromagnetic parameters of the ground plane by creating a high capacitive impedance surface through an array of conducting pins with specific dimensions and spacing. The pin height, diameter, and spacing are optimized to achieve capacitive impedance values that suppress multipath signals while maintaining sensitivity to low-elevated satellites, achieving positioning accuracy of ±1 mm
Solution Approach 2:
The patent employs a composite structure combining conducting pins mounted on a conductive sheet, creating a composite ground plane with high capacitive impedance. This composite configuration produces electromagnetic effects that simultaneously suppress multipath reception and maintain satellite signal sensitivity, overcoming the limitations of conventional single-material ground planes
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 configuration significantly improves positioning accuracy by suppressing multipath signals, reducing errors to about ±1 mm, a tenfold improvement over conventional choke-ring antennas, while maintaining sensitivity to low-elevated satellites.
Implementation Method 1
An antenna system features a high capacitive impedance surface (HCIS) ground plane and an antenna positioned above it
Data Source
AI summary
An antenna system for a global navigation satellite system reference base station is disclosed. The antenna system includes an antenna positioned above a high capacitive impedance surface (HCIS) ground plane. Over a specific range of the lateral dimension of the HCIS ground plane and the height of the antenna above the HCIS ground plane, a high level of multipath suppression and high sensitivity for low-elevated satellites can be simultaneously maintained. The HCIS ground plane can be fabricated as a flat conducting plate with an array of conducting elements such as pins, pins with expanded tips, or mushroom structures. Alternatively, the HCIS can be fabricated as a flat conducting plate with a concentric series of choke rings. The antenna system can provide a positioning accuracy of +/-1 mm, an order of magnitude improvement over previous designs.