Projectile Course Correction Using Sensor-Refined Trajectories

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing guided munition course correction systems are ineffective in contested spaces where GPS signals can be jammed or spoofed, leading to reduced accuracy and increased uncertainty in projectile trajectory.

Innovation Solution

A pre-steering trajectory determination module that uses onboard sensors and a physical model to refine possible trajectories through Monte Carlo simulations, providing refined position, velocity, and dynamic pressure values for steering control, allowing for midcourse corrections without relying on GPS.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GPS-based course correction is used, then positioning accuracy is improved, but vulnerability to jamming and spoofing increases in contested spaces

Engineering Contradiction:
Improvepositioning accuracyVSAvoidsystem reliability in contested spaces
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces an intermediary inertial measurement unit (IMU) system that mediates between the vulnerable GPS receiver and the guidance control system. The IMU provides independent inertial navigation capability that does not rely on external signals, thereby protecting the guidance system from GPS jamming and spoofing while maintaining positioning accuracy through sensor fusion algorithms.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the operational parameters of the navigation system by switching from pure GPS-dependent operation to a hybrid mode that incorporates IMU data. This parameter change includes adjusting the weightings in sensor fusion algorithms, modifying update rates, and changing the mathematical models used for trajectory prediction, thereby maintaining reliability under contested conditions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If GPS receiver is removed to eliminate vulnerability, then reliability in contested spaces is improved, but positioning accuracy deteriorates

Engineering Contradiction:
Improvesystem reliability in contested spacesVSAvoidpositioning accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent merges the GPS receiver with an inertial measurement unit (IMU) to create a hybrid navigation system. This combination allows the system to maintain high positioning accuracy by fusing data from both GPS and IMU sensors, while the IMU provides backup capability that ensures reliability even when GPS signals are denied or contested.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements feedback mechanisms where the IMU continuously monitors and compensates for GPS errors, and vice versa. The sensor fusion algorithm processes feedback from both sensors to optimize positioning accuracy, adjusting the contribution of each sensor based on their respective confidence levels and environmental conditions.

Inventive Principle:
Principle #23Feedback

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 solution significantly reduces uncertainty in projectile trajectory, enabling accurate targeting even in GPS-denied environments by utilizing existing sensors and processing capabilities, thereby minimizing the seeker basket area and reducing collateral damage.

Implementation Method 1

The estimation module can be configured to execute a computational algorithm that inputs a plurality of randomized values into the physical model to create a plurality of output possible trajectories per time instance. For example, the computational algorithm can be a Monte Carlo simulation.

Methodology Applied
Scientific EffectMonte Carlo simulation:

Implementation Method 2

a physical model defining trajectory as a function of gravitational pull and one or more launch variables

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 3

The sensor data can include heading and pitch angle

Methodology Applied
Scientific EffectSensor measurement:

Data Source

PatentEP3961145A1Course correction systems for projectiles
Publication Date: 2022.03.02 RAYTHEON CO
  • EP3961145A1 patent drawingFigure 1
  • EP3961145A1 patent drawingFigure 2
  • EP3961145A1 patent drawingFigure 3

AI summary

A course correction system (100) for a projectile can include a pre-steering trajectory determination module (101). The pre-steering trajectory determination module can be configured to receive a series of possible trajectories from an estimation module (103) including a physical model defining trajectory as a function of gravitational pull and one or more launch variables, and receive a sensor data from one or more on-board sensors (105) of the projectile. The pre-steering trajectory determination module can also be configured to reduce the possible trajectories from the estimation module to one or more refined trajectories using the sensor data, and output the one or more refined trajectories.