Projectile Control Using Doppler Navigation Without GNSS
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Solution Overview
Problem
Existing methods for controlling projectiles, such as steering or activating fuzes, are not sufficiently robust, accurate, or reliable due to reliance on Global Navigation Satellite System (GNSS) which is prone to spoofing and interference, and electro-mechanical sensors struggle to accurately measure rotational frequency.
Innovation Solution
A control system using a plurality of transmitters that transmit electromagnetic waves, a receiver on the projectile to determine position, velocity, or acceleration, and a controller to generate control signals based on Doppler measurements, allowing for robust control even when GNSS is unavailable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GNSS is used for navigation of the projectile, then positioning capability is provided, but reliability and accuracy deteriorate due to spoofing and interference
Solution Approach 1:
The patent introduces ground-based transmitters as intermediary components that emit electromagnetic waves for the projectile to measure its position and velocity. These transmitters serve as trusted intermediaries that cannot be easily spoofed or interfered with, replacing the vulnerable GNSS satellite system while maintaining positioning and navigation capabilities
Solution Approach 2:
The patent replaces the electronic/GNSS-based navigation system with a physics-based measurement system using electromagnetic wave Doppler effects. By substituting the vulnerable electronic GNSS receiver with a system that measures physical Doppler shifts from ground transmitters, the system achieves improved reliability against spoofing and interference
2Measurement precision
If electro-mechanical sensors are used to measure rotational frequency, then rotational information is obtained, but measurement precision deteriorates
Solution Approach 1:
The patent replaces complex electro-mechanical rotational sensors with a signal-processing-based approach that derives rotational frequency from electromagnetic wave measurements. By using the Doppler effect measurements from ground transmitters and processing the signal mathematically, the system obtains precise rotational information without mechanical moving parts
Solution Approach 2:
The navigation system serves multiple functions simultaneously - it measures position, velocity, and rotational frequency all from the same electromagnetic wave measurements. The single measurement system provides multiple pieces of information needed for complete projectile control, eliminating the need for separate specialized sensors
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
Enables accurate and reliable control of projectiles by determining position, velocity, or acceleration using Doppler measurements, improving steering accuracy and fuze activation, even in conditions where GNSS is unreliable.
Implementation Method 1
determine at least one of a position, a velocity or an acceleration of the projectile from transmission positions of the plurality of transmitters and Doppler measurements derived from the received plurality of electromagnetic waves
Data Source
Figure 1~2A
Figure 2B
Figure 3A~3B
AI summary
According to an aspect of the invention, there is provided a control system (1000) for controlling a projectile (4), the control system comprising: a plurality of transmitters (210a-d), wherein each transmitter of the plurality of transmitters (210a-d) is arranged to transmit an electromagnetic wave (21a-d) from a transmission position; a receiver associated with the projectile (4), the receiver being arranged to receive a plurality of electromagnetic waves (21a-d) transmitted from the plurality of transmitters (210a-d); a controller associated with the projectile (4), the controller being arranged to: determine at least one of a position, a velocity or an acceleration of the projectile (4) from transmission positions of the plurality of transmitters (210a-d) and Doppler measurements derived from the received plurality of electromagnetic waves (21a-d); and generate a control signal for performing an action with the projectile (4) depending on the determined at least one of position, velocity or acceleration of the projectile (4).