Polarized RF Positioning for Munitions Against GPS Jamming
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Solution Overview
Problem
GPS signals are unreliable for munitions guidance due to signal loss, jamming, and weak signals, making it difficult to provide accurate and secure position and orientation information for smart and guided projectiles.
Innovation Solution
A non-GPS local full position and orientation referencing system using polarized RF sensors that measure angular orientation (pitch, yaw, and roll) autonomously, allowing munitions to determine their position and orientation relative to a fixed or moving object, even in harsh environments, and can network with other systems for enhanced accuracy and range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS is used for position and orientation referencing, then position information can be provided to munitions, but GPS signals may not be available along the full path of flight and are prone to jamming
Solution Approach 1:
The patent introduces polarized RF reference sources as intermediary elements deployed in the operational environment. These reference sources act as mediators between the munition and the positioning system, providing local reference signals that enable autonomous position and orientation determination without relying on external GPS satellites, thereby resolving the signal availability and jamming issues
Solution Approach 2:
The patent replaces the GPS satellite-based electromagnetic positioning system with a local polarized RF reference system. By substituting the external satellite infrastructure with locally deployed polarized RF reference sources, the system achieves autonomous positioning that is immune to GPS signal loss and jamming, while providing full position and orientation information
2Measurement precision
If GPS is used for position referencing, then position data can be obtained, but measurements cannot be made fast enough for flight control purposes in gun fired munitions
Solution Approach 1:
The patent deploys polarized RF reference sources in advance throughout the operational area before munition flight. These pre-positioned reference sources are ready to immediately provide position and orientation measurements as the munition passes through their coverage zones, eliminating the need for real-time satellite signal acquisition and enabling fast measurements suitable for flight control
3Measurement precision
If polarized RF sensors are used to measure full angular orientation, then precise pitch, yaw, and roll measurements can be obtained, but the system complexity increases
Solution Approach 1:
The patent designs the polarized RF sensor to perform multiple functions: it measures all three angular orientations (pitch, yaw, roll) simultaneously, provides position information, and operates autonomously without external references. This multi-functionality consolidates what would otherwise require multiple separate sensors into a single integrated system, managing complexity while delivering comprehensive measurement capabilities
4Reliability
If a local position and orientation referencing system is established, then accurate and secure position data can be provided, but the system requires deployment of reference sources and sensors
Solution Approach 1:
The patent divides the positioning system into separate functional segments: polarized RF reference sources deployed in the environment and polarized RF sensors installed on munitions. This segmentation allows independent optimization and deployment of each component, with reference sources forming the infrastructure and sensors providing autonomous measurement capabilities, simplifying overall system deployment while maintaining high security and reliability
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 system provides highly precise and secure position and orientation data, reducing guidance and control errors, and is robust, low-power, and resistant to detection and spoofing, with an operational range of over 30 km and sub-degree orientation accuracy.
Implementation Method 1
The polarized RF based position and angular orientation sensors, when embedded in munitions, can measure full angular orientation (pitch, yaw, and roll) of the projectile relative to a fixed ground (base) station, or relative to a moving object
Data Source
AI summary
A method for setting up a reference coordinate system including: providing an object with sensors having a geometrical cavity with a pick up terminal configured to provide an output that varies with orientation of the sensors with respect to a direction of an incoming polarized RF plane of polarization; using polarized RF reference sources each having two polarization planes offset from each other and different from polarization fields of other references sources; amplitude modulating the two polarization planes for each of the reference sources to define a time varying linear polarization vector for each of the reference sources; and determining, for each of the reference sources, the position and orientation of the object relative to the reference coordinate system based on a measured amplitude of the time varying linear polarization vector at the sensors, a predetermined mapping function and a predetermined scanning pattern of the time varying linear polarization vector.