Domed-Array GNSS Antenna With Coupled Petals for Low-Elevation Tracking
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Solution Overview
Problem
Existing GNSS antennas struggle with low elevation tracking, phase center variation, and narrow bandwidth, which affect the precision and reliability of GNSS receivers, especially in applications requiring high accuracy.
Innovation Solution
The design of a GNSS antenna employing pairs of electromagnetically coupled petals and dipoles with a distributed feed network, optimized for wide bandwidth, low elevation tracking, and improved phase center stability, using parasitic resonators and balanced feed configurations to enhance azimuthal performance and polarization purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional GNSS antenna designs are used, then the antenna structure is simple, but the bandwidth is narrow and low elevation tracking is poor
Solution Approach 1:
The antenna is divided into multiple petal-shaped elements (typically 4-8 petals) arranged radially around a central feed point. Each petal is independently fed through a dipole structure, allowing the antenna to achieve wide bandwidth through the combined response of multiple segments while maintaining a relatively simple overall configuration.
Solution Approach 2:
The antenna transitions from a planar two-dimensional structure to a three-dimensional radial configuration with petals extending in multiple directions. This dimensional change enables the antenna to capture signals from all azimuth angles and improve low-elevation tracking while maintaining compact form factor.
2Measurement precision
If conventional antenna elements are used, then the antenna is compact, but phase center variation is significant
Solution Approach 1:
Multiple dipole elements are merged into a single centralized feed point through a distributed feed network. This merging of multiple feeding paths into one common point stabilizes the phase center location, reducing phase center variation while the distributed nature of the feed network maintains design simplicity.
Solution Approach 2:
The feed network employs asymmetric impedance transformation structures and unequal length transmission lines to compensate for phase differences among the multiple petal elements. This asymmetric design equalizes the electrical path lengths from each petal to the central feed point, thereby stabilizing the phase center.
3Ease of manufacture
If simple dipole elements are used, then the antenna is easy to manufacture, but azimuthal performance is poor
Solution Approach 1:
The antenna elements are designed with curved petal-shaped geometries instead of straight linear dipoles. These curved petals are arranged radially to form a spherical or hemispherical radiation pattern, improving azimuthal coverage and low-elevation tracking while maintaining manufacturability through standard PCB fabrication techniques.
4Reliability
If the antenna operates at low elevation angles, then horizon tracking is improved, but signal strength decreases
Solution Approach 1:
The antenna utilizes a three-dimensional radial petal configuration that extends the effective aperture in the horizontal plane. This dimensional arrangement improves the antenna's ability to capture weak signals from low-elevation satellites by presenting a larger effective area to horizon-ward incident waves without compromising gain at higher elevations.
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 provides enhanced azimuthal performance, wide bandwidth, and improved phase center stability, enabling high-precision GNSS reception even at low elevations, reducing multipath interference and enhancing the accuracy of GNSS receivers.
Implementation Method 1
employing one or more pairs of antenna elements each electromagnetically coupled to a dipole
Implementation Method 2
using parasitic resonators and balanced feed configurations to enhance azimuthal performance
Data Source
Figure 1A~1B
Figure 2~3
Figure 3B~4
AI summary
The design of a Global Navigation Satellite System (GNSS) antenna requires consideration of a range of characteristics including, for example, the ability for tracking satellites at low elevation, phase centre variation (PCV), antenna efficiency and impedance, axial ratio and up-down ratio (UDR), antenna bandwidth, etc. whilst also providing a light weight, compact and robust form factor. For rover applications this becomes particularly important when the satellites being accessed may be at low elevations where prior art GNSS antenna exhibit poor performance. To address this a GNSS antenna is provided comprising a domed array of opposed metallized antenna elements which are indirectly coupled via a pair of dipoles to the feed network thereby avoiding the difficulties associated with direct electrical connections of feed circuits to antenna elements.