Table of Contents

Preface

Chapter 1.0 Introduction

Chapter 2.0 LOS Control Architecture and Design

2.1 Direct LOS Stabilization
2.2 Indirect LOS Stabilization
2.3 Pointing Performance Error Budgets
2.4 Design Criteria and Methodology
2.5 LOS Control Operating Modes
2.6 LOS Control with Multi-Axis Gimbals

Chapter 3.0 The LOS Stabilization Servo Problem

3.1 Gimbal Motor Drive
3.2 Basic LOS Stabilization Servo Design
3.2.1 Direct LOS Stabilization
3.2.2 Indirect LOS Stabilization
3.2.3 Track Loop Impact on Stabilization

Chapter 4.0 LOS Control Design Summary

4.1 Analyzing the LOS Control System Requirements
4.2 The Disturbance Environment and Error Budget
4.3 Disturbance Rejection and Bandwidth Determination
4.4 Gimbal Configuration and Control Loop Design

Chapter 5.0 Two-Axis Rigid Body Dynamics and Controls

5.1 Two-Axis Gimbaled Dynamics and Control
5.2 Elevation Axis Dynamics
5.3 Elevation Axis Direct Stabilization Control
5.4 Elevation Axis Indirect Stabilization Control
5.5 Cross Elevation Dynamics
5.6 Cross Elevation Direct Stabilization Control
5.7 Cross Elevation Axis Indirect Stabilization Control
5.8 Stabilization Control Loop Servo Stability
5.9 Alternative LOS Stabilization Control Techniques

Chapter 6.0 LOS Stabilization with a Steering Mirror

6.1 Mirror Elevation Axis LOS Dynamics
6.2 Direct Stabilization Control Using a Stable Body
6.3 Mirror Cross Elevation Axis LOS Dynamics
6.4 Direct Stabilization Control Using a Stable Body
6.5 Mirror Stabilization Control Loop Stability

Chapter 7.0 LOS Disturbances

7.1 Track Following Error
7.2 Sensor Accuracy and Noise
7.3 Atmospheric Induced Sensor Noise
7.4 Alignment
7.5 Jitter from Residual Stabilization
7.5.1 Imbalance
7.5.2 Residual Motion from Platform Acceleration
7.5.3 Air stream Turbulence Torques
7.5.4 Structural Vibration
7.5.5 Friction
7.5.5.1 Static Friction
7.5.5.2 Dynamic Friction
7.5.6 Cable Restraint Torques
7.5.7 Reaction Torques
7.5.8 Cross Product Torques
7.5.9 Gyro Noise
7.5.10 Servo/Processor Noise
7.5.11 Motor Ripple/Cogging

Chapter 8.0 LOS Control Component Specifications

8.1 Inertial Stabilization Sensors
8.1.1 Rate Sensors
8.1.2 Magnetic Hydrodynamic
8.1.3 Spinning Mass Gyro
8.1.4 Ring Laser Gyro
8.1.5 Fiber Optic Gyro
8.1.6 Inertial Measurement Units
8.1.7 Inertial Navigation Systems
8.1.8 Gyro and INS Specifications
8.1.8.1 Gyro Drift/Bias
8.1.8.2 Gyro Scale Factor Error
8.1.8.3 Gyro Excitation Noise
8.1.8.4 Misalignment
8.1.8.5 Gyro Random Walk
8.1.8.6 INS Related Errors
8.1.8.6.1 Long-time Unaided INS Accuracy
8.1.8.6.2 Short-time Unaided INS Accuracy
8.1.8.6.3 Position and Velocity Aiding
8.2 Rotary Position Sensors
8.2.1 Resolvers
8.2.2 Encoders
8.2.3 Potentiometers
8.2.4 Other Rotary Position Sensor Types
8.2.5 Rotary Position Sensor Performance
8.2.5.1 Component Resolution Limitations
8.2.5.2 Mechanical and Electrical Component Error
8.2.5.3 Total Rotary Position Error
8.3 Motors

Chapter 9.0 LOS Stabilization Preliminary Design Example

9.1 Pointing Requirement
9.2 Elevation LOS Control Design
9.2.1 Disturbance Related Accelerations
9.2.2 Stabilization Servo Loop Bandwidth Estimation
9.2.3 Slew Related Accelerations
9.2.4 Total Acceleration and Torque
9.2.5 Elevation Error Budget
9.2.6 Elevation Positioning Requirements
9.3 Cross Elevation LOS Control Design
9.3.1 Disturbance Related Accelerations
9.3.2 Stabilization Servo Loop Bandwidth Estimation
9.3.3 Slew Related Accelerations
9.3.4 Total Acceleration
9.3.5 Cross Elevation Error Budget
9.3.6 Azimuth Positioning Requirements

List of Appendices

Appendix A Parameterization of Mass Imbalance Torque
Appendix B 2-Axis Gimbal Kinematics
Appendix C Simple Cross Elevation Dynamics and Direct Control Model
Appendix D 2-Axis Gimbal LOS Dynamics State Equation
Appendix E Local Stability Conditions for LOS Dynamics
Appendix F 2-Axis Mirror Kinematics
Appendix G Local Stability Conditions for Mirror LOS Dynamics
Appendix H 2-Axis Mirror Stability Analysis Bound

References