Compact GPS Antenna with Multi-Pattern Adaptive Anti-Jam Processing
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Solution Overview
Problem
Existing airborne GPS antennas lack multi-beam capabilities necessary for effective anti-jam adaptive processing, particularly in small form factors required for military and drone applications, where size, weight, and complexity constraints limit the implementation of anti-jam techniques.
Innovation Solution
A compact GPS antenna design featuring an array of eight radiating elements with a Butler-type excitation network, providing up to eight selectively usable antenna patterns, including omnidirectional and progressive phase patterns, to enable adaptive anti-jam operations with omnidirectional hemispherical coverage and low-profile configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a fixed radiation pattern antenna is used for GPS operation, then the antenna size can be kept small, but the antenna provides no multi-pattern capability to support adaptive processing for anti-jam operation
Solution Approach 1:
The antenna system is segmented into multiple independent radiating elements (at least four elements) that can be individually excited and controlled. Each element contributes to forming different radiation patterns when activated in specific combinations, enabling the small antenna to provide multiple beam patterns necessary for adaptive anti-jam processing without increasing overall antenna volume.
Solution Approach 2:
The antenna system achieves multi-functionality by designing a single small antenna structure that can generate multiple radiation patterns (omnidirectional, directional, notched patterns) through different excitation configurations of its radiating elements. This universal design allows the same physical antenna to adapt to various operational requirements including GPS reception and anti-jam modes.
2Reliability
If adaptive processing techniques are implemented for anti-jam capability, then reception in the presence of interference is improved, but the antenna requires multi-beam capability which increases device complexity
Solution Approach 1:
The antenna is divided into multiple discrete radiating elements that can be independently controlled through an excitation network. This segmentation allows the system to generate multiple beam patterns and apply adaptive processing techniques by selectively exciting different element combinations, providing anti-jam capability through controlled pattern formation rather than complex physical structures.
Solution Approach 2:
The antenna system incorporates dynamic control through an excitation network that can adjust the amplitude and phase of signals to each radiating element in real-time. This dynamic excitation capability enables the antenna to adapt its radiation pattern continuously, steering nulls toward jamming sources and maintaining reliable GPS reception under varying interference conditions without requiring mechanically complex structures.
3Object-affected harmful factors
If reduced-gain antenna pattern notches are aligned to suppress reception at the azimuth of interference signals, then interference suppression is improved, but the solution becomes inadequate for airborne operations where interference azimuth changes constantly
Solution Approach 1:
The antenna system employs dynamic pattern control through its excitation network, which can continuously adjust the radiation pattern to track and suppress interference from changing azimuths. By dynamically reconfiguring the excitation of multiple radiating elements, the system maintains effective null steering capability across all azimuth directions, making it suitable for airborne operations where interference sources move relative to the platform.
Solution Approach 2:
The multi-element antenna design provides universal interference suppression capability across all azimuths by combining multiple radiating elements that can be excited in various patterns. This universal coverage allows the system to effectively suppress jamming signals regardless of their incident direction, overcoming the limitation of fixed-pattern notches while maintaining adaptability to changing interference conditions.
Data Source
AI summary
A GPS antenna with anti-jam capabilities utilizes eight resonant loop radiator elements in a resonant exciter configuration to make available a primary and up to seven auxiliary antenna patterns usable with multi-pattern adaptive processing for anti-jam operation. Antennas as described enable desired radiation characteristics to be provided in a configuration of small size suitable for replacement of existing GPS aircraft antennas which lack anti-jam capabilities, in order to enable reliable GPS reception during airborne operations in the presence of interference or jamming. With enablement of multi-pattern adaptive processing, reduced-gain pattern notches or nulls may be employed to track and reduce the effect of incident signals which would otherwise jam or interfere with reception of GPS signals.