Attitude Data Link (ADL) Attitude data simulators Examples of structure Functional requirements Attitude determination (See alst specific method, e.g. Earth

Areas of current work Block averaging Definitive vs. real time Deterministic methods —Advantages of —Solution behavior width/Sun

2, 343-484 715 370-373 «81 362-435 437-438 402-408

Deterministic vs. state estimation 436-438 Example of 10-14

Example of function of 7

Functions of 2

Hardware (See Altitude sensors) Introduction to analysis 343-361

Methods of 16-18

Mission support software 681-713

Needed analytic projects 112-TH

Proc. for elim. data anomalies 334-339 Reference sources, table of 17

Reference vector 10

—Attitude accuracy limits 393-397

Single axis 362-409

Spinning spacecraft 363-370

Star sensor methods 703-709

Three-axis 420-428

Uncertainties 345-346

—Expressions for 375-376,381-382,384 Attitude determination accuracy 397

Analytic solutions for 373-402

Direct calculation of 373,429-435

Effect of Earth oblateness 105

Estimating systematic error 476

Estimating systematic uncertainty 402-408 Evolution of over time 714

For continuous measurements 376-382 For correlated uncertainties

382-383, 431-432 For nonorthogonal measurements 377-382 For orthogonal measurements 376-377 For quantized measurements 374-376,431 For uncorrelated uncertainties

374-382,431-432 Geometrical limitations on 389-402

Identification of singularities 406-407

Limited by systematic error 476

Sample computation (IUE) 384-386

Single axis 373-409

Single frame, summary table 384

Spacecraft requirements, list of 7%

Three axis 429-434

Attitude disturbance torques (See

Disturbance torques) Attitude dynamics 487-587

Flexible spacecraft 548-556

Introduction to 487,498-502

Mathematical models 521-523

Model of, in state vector formulation 440 —For attitude propagation 558-559

Attitude error ellipse (See Error ellipse) Attitude error parallelogram (See Error parallelogram) Attitude extrapolation, for star sensor attitude determination ' 705-706

Attitude geometry (See also Global geometry plots) 22-35

As limitation on attitude accuracy 389-402 For single-axis attitude solutions 362-402 Unresolved analytic problems 723

Attitude kinematics 510-521

Approximate closed-form solutions for 564-566

Equations for attitude propagation 558-559 Introduction to 4&I-497

Model of, in state vector formulation 440 Attitude maneuver control 2.502,636-678 Attitude maneuver control program for

CTS spacecraft 700, 703

Attitude maneuver monitoring, in CTS

attitude system 702-703

Software for 700

Attitude matrix (See Direction cosine matrix) Attitude measurements (See also Arc length measurement; Compound altitude measurement; Rotation angle measurement) Equivalence of 344

Intersection of loci 344-346

Types of 346

Attitude measurement density 345-346

As limit on attitude accuracy 392-393,394-396

Expressions for 384, 386-388

For rotation angles 352

Attitude measurement uncertainty (See Attitude determination accuracy; Uncertainty) Attitude motion (See also Attitude kinematics; Attitude Dynamics) Math, model for gyro measurement of 267 Attitude perturbations, due to flexible spacecraft 548-556

Attitude prediction (attitude propagation) 2,558-587

Accuracy of for H EAO-1 708-709

Attitude sensor electronics 242-249'

Attitude Sensor Unit (combined Earth/Sun sensor) 155-201, 178-179

Attitude sensors (See also item sensed, e.g. Horizon sensors) 10

Distinction between hardware & math.

models 217

Listed by spacecraft & sensor type 797 Mathematical models 217-270

Need for standardization 718-721

Representative telemetry data errors 311 Simple vs. complex designs 716-718

Use in attitude control loop 502

Attftude stabilization (See also

Stabilization methods, e.g^ magnetic stabilization) 2-3. 502, 588-635

Spacecraft listed by method 787

Table of methods 19

Attitude stabilization systems 604-625

AU (See Astronomical unit) Automatic control of spacecraft (See also

Onboard control; Inertial guidance) Automatic threshold adjust (for digital Sun sensor) 163-165

Autumnal equinox 27

Symbol for SO Averaged attitude solution, estimating reliability of 373

Averaging of attitude solutions 370-373

Axial symmetry 524

Azimuth angle, attitude component 360' Component of a spherical coordinate system 25 Determination of, for spin-stabilized spacecraft 366

Azimuth biases 239-242

In horizon sensors 235 Azur (German Research Satellite)—

Attitude system of 788-789

Baffles, in fuel tanks 578

Ball-in-tubc nutation damper 626,627

Ballistic coefficient 64

Ballistic trajectory 52

Bang-bang control law 593

Example of 655-658

Bang-bang-plus-dead-zone control law 593

Bar (unit of pressure) 809

Bary center 38 Batch estimator 437,439,448 For star data 704,707-709

Batch least-squares estimator 448-456

Advantages & disadvantages 456

Convergence 455-456 Example of 454-455,456-459

Batch mode of program operation 686

Bays, magnetic 123

BC/CD/CPD Number (star catalogs) 143

Bending stiffness, of spacecraft booms 548-549

Bessei, Friedrich WHhelm 45

Betelgeuse (star), angular diameter of 167 Bias determination (See also Differential correction; estimation theory)

Application of scalar checking to 329-330

Choice of observation models for 447 Choice of state vector elements, example 440-441

Geometrical conditions for 478-483

Need for 407-408

Need for "simple" sensors for 717-718

Operational procedures for 473-476

Bias momentum, dual-spin spacecraft 610 Biases (See individual item; e.g, Magnetometer biases) Effect on deterministic solution behavior 404

Types of 477

Binary codes 295-298

Blpropellant gas jet 206

Block (of attitude solutions) 370

Block averaging 370-373

Block diagram, for control system 588

Bode's law 49

Body cone 491-492

Body-fixed coordinates (See Spacecrajt-

Body-mounted horizon sensor 169,173

Mathematical models 231-237

Body notation rate 490,525-526,535

Bolometer, as energy detector for horizon sensor 171,178

Misalignment of in wheel-mounted horizon sensor 236-237

Bond albedo 79

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