NASA Technical Reports Server (NTRS) 20080005029: Method and apparatus for reducing spacecraft instrument induced jitter via multifrequency cancellation

20 Pages·1.1 MB·English

by  NASA Technical Reports Server (NTRS)

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US006339734B3
United States Patent
(12) (io) Patent No.: US 6,339,734 B1
Liu et al. (45) Date of Patent: Jan. 15,2002
(54) METHOD AND APPARATUS FOR Woodard et al.; Measured spacecraft dynamic effects on
REDUCING SPACECRAFT INSTRUMENT atmospheric science instruments; Geoscience and Remote
INDUCED JITTER VIA MULTIFREQUENCY Sensing, IEEE Trans,; Mar. 1998; vol. 36, iss. 2; pp.
CANCELLATION 359-367.*
(75) Inventors: Ketao Liu, Cerritos; David S. * cited by examiner
Uetrecht, Palos Verdes, both of CA
(US) Primary Examineraichael J. Zanelli
(74) Attorney, Agent, or Firmqates & Cooper LLP
(73) Assignee: Hughes Electronics Corporation, El
Segundo, CA (US) (57) ABSTRACT
A method, apparatus, article of manufacture, and a memory
(*) Notice: Subject to any disclaimer, the term of this
structure for compensating for instrument induced space-
patent is extended or adjusted under 35
craft jitter is disclosed. The apparatus comprises a spacecraft
U.S.C. 154(b) by 0 days.
control processor for producing an actuator command
signal, a signal generator, for producing a cancellation signal
(21) Appl. No.: 09/510,136
having at least one harmonic having a frequency and an
(22) Filed: Feb. 22, 2000 amplitude substantially equal to that of a disturbance har-
monic interacting with a spacecraft structural resonance and
(51) Int. Cl? ............................ G06F 17/00; B64G 1/38 a phase substantially out of phase with the disturbance
(52) U.S. C1. .......................................... 701/13; 2441164 harmonic interacting with the spacecraft structural
(58) Field of Search ............................ 701113; 2441164, resonance, and at least one spacecraft control actuator,
2441170, 189, 171, 173 communicatively coupled to the spacecraft control proces-
sor and the signal generator for inducing satellite motion
(56) References Cited according to the actuator command signal and the cancel-
lation signal. The method comprises the steps of generating
U.S. PATENT DOCUMENTS
a cancellation signal having at least one harmonic having a
5,025,381 A * 611991 Goodzeit et al. ............. 701113 frequency and an amplitude substantially equal to that of a
5,654,549 A * 811997 Landecker et al. ......... 2501332 disturbance harmonic interacting with a spacecraft structural
resonance and a phase substantially out of phase with the
FOREIGN PATENT DOCUMENTS
disturbance harmonic interacting with the spacecraft struc-
JP 6-72396 * 311994 tural resonance, and providing the cancellation signal to a
spacecraft control actuator. The apparatus comprises a stor-
OTHER PUBLICATIONS
age device tangibly embodying the method steps described
Sen M. Kuo and Dennis R. Morgan, "Active Noise Control: above.
ATutorial Review", Jun. 1999, vol. 87 No. 6 Proceedings Of
The IEEE, pp. 941-973. 29 Claims, 12 Drawing Sheets
I I
308 CAN. SIOGN. M/OAFGF,' SFIRGENQA.L, PHASE I SCAN C0I MIM"A"-N U
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CANCELLA TlON INSTRUMENT(S)
SIGNAL
GENERAT OR
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US. Patent
Jan. 15,2002 Sheet 1 of 12 US 6,339,734 B1
X /
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YAW
ROLL
0
704s
/
1
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FIG. I
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/-
PITCH
Y
US. Patent
Jan. 15,2002 Sheet 2 of 12 US 6,339,734 B1
LOAD SHEDDING
222 BATTERY CHARGlNE 224
f 1 I \ ~
I
204
TRANSFER , @ TORQUER
ORBIT SUN DECODER
SENSOR UNIT
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2\3 0 LAM THRUSTER
THRUSTER
CQUlSlTlON SUN 4I VALVE kk 2 3 2
SENSOR(S) 272 ~~~
DRIVER UNIT
- ACS THRUSTER
^^^
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INERTIAL
REFERENCE
UNIT
-
ELECT. r 238
242
-
MOMENTUM MOMENTUM
- OR 244 OR
u I REACTION REACTION
WHEEL ASSY WHEEL ASSY
f 212
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OPERATIONAL SPACECRAFT 266
CONTROL -
ORBIT EARTH
SENSOR(S) PROCESSOR II
FEEDBACK
24\6 (-. 268
I -4 4Y-
H
NORMAL MODE WNIN.SGo LDARRIV E
WIDE ANGLE SUN
SENSOR(S)
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216
MAGNETO- EAST RPM
ME TER(S)
u
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STAR SENSOR(S)
FROM GND
STATlON 278
FIG. 2
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US. Patent Jan. 15,2002 Sheet 3 of 12 US 6,339,734 B1
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US. Patent
Jan. 15,2002 Sheet 4 of 12 US 6,339,734 B1
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US. Patent
Jan. 15,2002 Sheet 5 of 12 US 6,339,734 B1
(7
START
GENERATE A CANCELLATION SIGNAL
HAVING AT LEAST ONE HARMONIC AND
502
AN AMPLITUDE SUBSTANTIALLY EQUAL
J
TO THAT OFA DISTURBANCE HARMONIC
INTERACTING WITH A SPACECRAFT
STRUCTURAL RESONANCE AND A PHASE
SUBSTANTIALLY OUT OF PHASE WITH TU€
DISTURBANCE HARMONIC
504
PROVIDE THE CANCELLATION SIGNAL TO
A SPACECRAFT CONTROL ACTUATOR
FIG. 5
US. Patent
Jan. 15,2002 Sheet 6 of 12 US 6,339,734 B1
ENTER
602
DETERMINE A TIME TO APPLY THE J
CANCELLATION SIGNAL TO THE
SPACECRAFT CONTROL ACTUATOR
604
APPLY THE CAN CELLA TlON SIGNAL
J
TO THE SPACECRAFT CONTROL
ACTUATOR AT THE DETERMINED
TIME
( )
RETURN
FIG. 6
US. Patent
Jan. 15,2002 Sheet 7 of 12 US 6,339,734 B1
ENTER
v
702
MEASURE SPACECRAFT
MOTION
T
704
PRODUCE A CANCELLATION
SIGNAL USING
MEASUREMENT OF
SPACAECRAFT MOT ION
RETURN
FIG. 7
US. Patent Jan. 15,2002 Sheet 8 of 12 US 6,339,734 B1
ENTER
v
802
DETERMINE AN ESTIMATE OF A
MAGNITUDE AND A ZERO CROSSING OF
SPACECRAFT JITTER
IJ
DETERMINE A FREQUENCY, MAGNITUDE, 804
AND PHASE OF THE CANCELLATION
SIGNAL FROM THE ESTIMATE OF THE
MAGNITUDE AND ZERO CROSSING OF
THE SPACECRAFT JITTER
DETERMINE A TIME FOR PROVIDING THE
CANCELLATION SIGNAL
GENERATE A CANCELLATION SIGNAL
ACCORDING TO THE DETERMINED
MAGNITUDE, AND PHASE OF
THE CANCELLATiON SIGNAL
PROVIDE THE GENERATED
CANCELLATION SIGNAL AT THE
DETERMINED TIME
A
RETURN
FIG. 8
US. Patent
Jan. 15,2002 Sheet 9 of 12 US 6,339,734 B1
DETERMINE A TIME-BASED
DISTURBANCE PROFILE
.c
COMPUTE A
FREQUENCY-BA SED
REPRESENTATION OF THE
DISTURBANCE PROFILE
I
DETERMINE THE
DISTURBANCE HARMONIC
INTERACTING WITH THE
SPACECRAFT STRUCTURAL
RESONANCE FROM THE
FREQUENCY-BASED
REPRESENTATION OF THE
DISTURBANCE PROFIL E
A
RETURN
FIG. 9