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Executive Summary:

Contents Page:

List of Figures:

Introduction:

(200 words)

Systems Overview:

When observing and investigating the ‘Missile Guidance System’ model it is important to first identify the key components, parameters and variables within the system and how each individually effect the circumstantial output of the complete model. As visualized below (see figure 1) the system involved in missile guidance is comprised by the three major subsystems, seeker and tracker, guidance and airframe and autopilot. These subsystems act in a two tier level of integration, acting in way that not only fulfils the individual’s subsystems needs but also the overall systems requirements.

Seeker/Tracker:

The first subsystem of the missile guidance system is responsible for the seeking and tracking component of the system. This subsystem relies on two major loops that both coordinate the seeker gimbals to ensure a proper configuration of the seeker dish in accordance with the target and secondly to ‘provide the guidance law with an estimate of the sightline rate’. The sightline rate estimate is fundamentally an estimated rate of change of the angular tracking error (e) and an estimated rate of change of the seeker dish. The first loop, the tracking loop takes values associated with the angular tracking error of the dish and the gimbal and applies a tracking gain constant of 0.05 seconds. This allows for the compromise in lowering noise transmission but maintaining a higher response speed. The second loop or the stabilisation loop is responsible for taking values identified in the tracker loop and applying a ‘stabilizing rate gyro’ bandwidth which is a limitation that allows for missile rotation rates.

Guidance:

Secondly when observing the guidance subsystem it is important to identify the two modes of operation being closed loop tracking and initial target position location. Both modes are operated through a Stateflow model. The initial target location loop works by receiving information regarding the location about the target and relaying information back to the seeker the gimbals. This can only occur once the target is within a specified beamwidth of the seeker. After a short delay the Stateflow allows a mode switch to closed loop tracking that guides the missile until impact using the theory of proportional navigation guidance. Proportional navigation guidance (PNG) law is a guidance law used primarily in homing missiles deriving from the theory of ‘line-of-sight’ guidance. The concept behind PNG is essentially when two objects line of sight does not change in relation to each other those objects are said to be on a collision course. This can be represented by the equation below.

Where is equal to the acceleration perpendicular to instantaneous line of sight, is equal to anywhere between the integers of three and five, this represents the proportionality constant. is the velocity and is the line-of-sight rate .

(500-750 words)

· Identify and describe key components, variables and parameters.

· Comment on structure of model e.g. two tier?

· Graphical representation provided and discussed.

· Describe behaviour of and interactions within the system.

Notes:

· Should include diagrams

Sensitivity Analysis:

(800-1000)

· Only conducted on the top 5-10 variables

· Include graph for each variable changed identify the differences and describe the change in the reference to the systems interactions. How the variable influences the model.

Notes:

· Aim for 8 (100 words per change) variable changes (major inputs impact the most important outputs)

· Order variables in order of importance

· Describe in detail the impact of the variable of the final output