RF Guidance Sensor for Gun-Launched Projectiles
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Solution Overview
Problem
Current inertial guidance systems for gun-fired munitions face challenges in surviving extreme launch accelerations and achieving rapid settling times, leading to insufficient sensitivity and precision for accurate target acquisition.
Innovation Solution
The system eliminates the need for gyroscopes and accelerometers by using a polarized RF beam to derive angular orientation and rate signals, and position information, allowing for precise guidance without the limitations of traditional inertial technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional inertial devices (accelerometers and gyroscopes) are used for guidance sensing, then position and orientation measurement capability is provided, but the devices cannot survive extreme launch accelerations (up to 120,000 g) and have long settling times (several milliseconds)
Solution Approach 1:
The patent replaces mechanical inertial sensors (accelerometers and gyroscopes) with an electromagnetic field-based RF sensing system. The system uses RF signals transmitted from ground stations and received by antenna elements on the projectile to derive position, velocity, and orientation information through signal processing, eliminating the need for mechanical sensors that cannot withstand extreme launch accelerations.
Solution Approach 2:
The patent introduces RF signals as an intermediary medium between the ground control system and the projectile. Ground-based RF transmitters send signals that interact with antenna elements on the projectile, and the reflected or received signals carry information about the projectile's state, enabling remote sensing without requiring resilient mechanical sensors on the projectile itself.
2Measurement precision
If traditional inertial devices are used, then guidance control feedback is provided, but the full-scale dynamic range must exceed 5% of maximum launch force which reduces measurement precision for flight conditions
Solution Approach 1:
The patent replaces mechanical inertial measurement units with an RF-based electromagnetic sensing system. The RF system measures position and orientation by analyzing the characteristics of RF signals received from ground stations, avoiding the need for mechanical sensors that must be designed with high dynamic range to survive launch accelerations, thereby maintaining high measurement precision throughout the flight.
3Reliability
If gyroscopes are used for angular rate measurement, then orientation control is enabled, but the system requires complex inertial sensor assemblies that increase device complexity and reduce reliability
Solution Approach 1:
The patent replaces mechanical gyroscopes with an RF-based system that derives angular rate information from the modulation of RF signals received by multiple antenna elements. The angular orientation and rate signals are obtained through signal processing of the RF polarized beam interaction with the antenna array, eliminating the need for complex mechanical gyroscopic assemblies.
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 approach significantly enhances sensor sensitivity and reduces settling time, enabling more accurate and rapid target acquisition, even in harsh launch environments, by leveraging RF triangulation and polarization sensing.
Implementation Method 1
The present invention eliminates the prior art requirement for gyroscopes and GPS devices by illuminating the projectile in flight with a polarized RF beam. By monitoring the polarization modulation of RF signals received from antenna elements mounted on the projectile, both angular orientation and angular rate signals can be derived
Implementation Method 2
Depending on the spacing and positional accuracies of the RF ground emitters, position information of the projectile may also be derived, which eliminates the need for accelerometers
Data Source
AI summary
A sensor system uses ground emitters to illuminate a projectile in flight with a polarized RF beam. By monitoring the polarization modulation of RF signals received from antenna elements mounted on the projectile, both angular orientation and angular rate signals can be derived and used in the inertial solution in place of the gyroscope. Depending on the spacing and positional accuracies of the RF ground emitters, position information of the projectile may also be derived, which eliminates the need for accelerometers. When RF signals of ground emitter/s are blocked from the guided projectile, the sensor deploys another plurality of RF antennas mounted on the projectile nose to determine position and velocity vectors and orientation of incoming targets.