Predictive Guidance Flight Trajectory Phasing
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Solution Overview
Problem
Conventional interceptor guidance systems face errors due to assumptions like constant gravity and thrust, leading to reduced accuracy and increased costs, requiring large and costly interceptors with sufficient fuel for long-range targeting.
Innovation Solution
Implementing a predictive guidance system with phases, including an initial unguided launch, a predictive phase using non-linear thrust profiles to position the interceptor on a zero effort miss trajectory, and a final phase with parallel guidance for accurate targeting, allowing for less expensive hardware and reduced fuel usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional guidance algorithms are used with assumptions of constant gravity and thrust, then the guidance system is simpler to implement, but the targeting accuracy deteriorates due to accumulated errors
Solution Approach 1:
The flight trajectory is divided into multiple phases (initial phase, predictive phase, final phase), each with its own guidance strategy. The predictive phase uses numerical propagation to calculate trajectories without simplifying assumptions, while other phases can use simpler methods, thus resolving the contradiction between complexity and accuracy.
Solution Approach 2:
The predictive phase performs preliminary trajectory calculations using numerical propagation to determine the optimal path before the final interception phase. This preliminary action accounts for non-linear effects in advance, improving final targeting accuracy without requiring complex real-time calculations during the critical final phase.
2Duration of action of moving object
If sufficient fuel payload is carried for long-range flight, then the interceptor can reach distant targets, but the interceptor size and system cost increase
Solution Approach 1:
The thrust profile is made dynamic and non-linear, with varying thrust magnitude throughout the flight. The interceptor uses high thrust during initial acceleration, reduces thrust during the predictive phase, and applies precise thrust only during the final phase, optimizing fuel consumption for long-range flight without requiring excessive fuel payload.
Solution Approach 2:
The guidance system changes operational parameters (thrust magnitude, flight path angle, velocity) throughout the trajectory based on numerical propagation calculations. This allows the interceptor to achieve long-range flight with optimized fuel consumption by adjusting parameters dynamically rather than maintaining constant high thrust.
3Device complexity
If constant thrust magnitude is used throughout flight, then the propulsion system is simpler to design, but the trajectory accuracy deteriorates due to inability to compensate for non-linear effects
Solution Approach 1:
The thrust is applied periodically rather than continuously, with distinct thrust arcs separated by coast phases. This periodic thrust application allows the simpler propulsion system to achieve accurate trajectories by concentrating thrust during critical phases while using numerical propagation to plan the overall non-linear trajectory.
Data Source
AI summary
The various technologies presented herein relate to utilizing predictive guidance during one or more phases of a trajectory flown by an interceptor during interception with a target. The trajectory of the interceptor comprises an initial phase, a predictive phase, and a final phase. The initial phase includes the launching of the interceptor and can be unguided. The predictive phase directs the interceptor towards the target, wherein the predictive phase utilizes predictive guidance to control the trajectory of the interceptor based upon a predicted location of the target relative to the current locations of the target and the interceptor. During the predictive phase, a motor(s) can be cycled on and off, causing a period(s) where the interceptor is being propelled by the ignited motor, and a period(s) where the interceptor is propelled by its own momentum after cessation of power from the motor, e.g., unpowered flight.