U

UBV magnitudes 144-145

UDU fUter 467

Uburu (See SAS)

Umbra 72

Uncertainty In attitude measurements 345-346 Correlated 374. 378-379. 382-383

Due to systematic errors 402-408. 476

Expressions for 375-376, 381-382. 384

Uncorrected 374-382

Uncertainty of state estimator solutions 476 Undershoot, in control systems 593

Unitary matrix 751

Unitary transformation 752

Units and conversion factors 807-813

19, 798, 801-802 Attached to data 298

Unpacking, of telemetry data 304-306

UNVEC (subroutine) 690

Uplink 278

Upper stage rocket vehicles 53

U.S. Coast Guard, time keeping system 299 U.S. Naval Observatory, time keeping system 299-300

U.S. Standard Atmosphere 110

UT (See Universal Time) UTC (See Universal Time; Coordinated

. Universal Time) Utility subroutines 690-695

V-brusb, Sun sensor code 163

V-slit Sun sensor (V beam Sun Sensor) 161 Mathematical model 218-221

Validation—

Data flags and sensor identification 313-314 Of attitude data 315-327

Of telemetry data 307.312-334

Requiring attitude information 334-339 Vandenberg Air Force Base, Calif. (See

Western Test Range) Vanguard (tracking ship) 284, 287

Vanguard units 808-809

Variance 429

Variation of parameters, formulation of attitude dynamics 531-534

VEC (subroutine) 690

Vector algebra 744-757

Subroutines 690-691

Vector calculus. 755-756

Vector identities, in three dimensions 756-757

Vector magnetometer, mathematical model 250-254 Vector multiplication, inner and outer products 747-748

Vector notation x, xii

Vector product (cross product) 756

Cqu* tion for direction of 728

Subroutine for (CROSSP) 691 Velocity—

In a Keplerian orbit 54,828

Units and conversion fact.jrs 809

Velocity of escape 42

Planets and satellites, table 817,825

Vernal equinox 27,48

Symbol for 50

VHF data transmission 282-283

Vidlcon, in star sensors 189 Viking (Mars mission), launch dates relative to opposition 51, 57-58

Vis viva controversy 38

Vis viva equation 38,42

Origin of 38 Viscous ring nutation damper 626,627-629

Visibility of satellites and spacecraft 80

Visibility of spacecraft 71-80 Visible light sensor (See also Horizon sensor) 83 Visual magnitude, for spacecraft, sample calculation 79

Volterra equation 773 VOP (See Variation of parameters)

VPHAZE (subroutine) 691

Wallops bland, launch site 4

Water, absorption bands 91-92

Weighting (in estimation theory) 449-450

Weighting data Weightlessness

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