ALOS Data Users Handbook

More documents

Recommendations

Info

Section 3 Outline of ALOS Satellite System3.3.7 Reaction Control Subsystem (RCS)ALOS's reaction control subsystem (RCS) has thrusters (gas jet modules) as the actuators for controlling thesatellite's attitude and orbit after ALOS - H-IIA separation. Two types of thrusters are assembled on ALOS's RCSaccording to its role.1[N] (about 100g) thrusters are used for attitude control. There are two sets of 1[N] thrusters (16 thrusters total)and another one set is on standby in the case of emergency. For orbit control, four 4[N] (about 400g) thrustersare used. They are organized for two pairs and ALOS can control its orbit another pair of 4[N] or 1[N] thrustersin the case of emergency.ALOS's RCS uses hydrazine as the fuel. In vacuum, fuel and oxidizer are needed for combustion. But hydrazinecombust with catalyzer dissocciating and generating hot gas without oxidizer. Hydrazine is widely used forsatellite's fuel because of simplicity of thrusters and components.ALOS has three tanks and total capacity of them is over 180kg. This capacity is enough for five years operationof ALOS's attitude and orbit control.3.4 Mission Instrument Observation Data3.4.1 PRISM Data FormatPRISM has six CCDs for the nadir telescope, and eight CCDs both for the forward and for the backwardrespectively, with each CCD consisting of 5,000 pixels arrayed in the cross track direction. In the normalobservation mode with 35km width, 14,592-pixel image data are output from each telescope from the presetextraction position incorporating correction of effects from the pointing angle and earth rotation, and29184-pixel data are output for the nadir 70km observation mode as well. The output data are divided into threesystems of 4,864 pixels (6 systems for the nadir 70km mode), and each data set is irreversibly compressed at theDC subsystem. The compressed data are assigned a VCID for each system and packetized, and then transmittedto ground. Figure 3.4-1 shows the observation data interface of PRISM.Where, the data interfaces for Calibration Mode 1 and Calibration Mode 2 are the same as that of ObservationMode 1.AUX data [status, high frequency angle sensor data (ADS data), imaging start time (line counter and GPS time)]3-28
ALOS Data Users Handbookand start position of extraction are attached with the image data. However, as for the 1st line data after PRISMDATA ENA (data output start) command sending, it cannot be defined because the residual data in the memory isoutput as in both image data and AUX data. Extraction start position immediately changes after commandtransmission for extraction start pixel position addressing (PRISM electronic pointing position addressing).Since image data deals with 16 lines as 1 block, it changes after a 1-block (16 lines) end.Total approx. 30,000 pixels (Nadir : equivalent to approx. 70km)approx. 40,000 pixels (Forward, Backward)Electrical extraction of 14,592 pixelsDivide into 4864 pixels x 3 systemsCCD LayoutSatellite FlightDirectionMissionTelemetryTime106.7Mbps x 3chto Data Compression systemCompresseddata of 16linesCompresseddata of 16linesCompresseddata of 16linescompress 3 chindividuallyCCSDSPacketFixed LengthFrameFixed LengthFrameFixed LengthFrameFrame Frame FrameVCID:38 VCID:37 VCID:36ForwardAPID: 1581 VCID:35VCID:34 VCID:33NadirFrame Frame FrameVCID:41 VCID:40 VCID:39BackwardFigure 3.4-1 PRISM Data Interface (Nominal Observation Mode)3-29
Page 3: Meantime, global environmental prob
Page 6 and 7: Table Of Contents6.1.2 Scene Defini
Page 8 and 9: Table Of ContentsTable 5.2-1 ALOS O
Page 10 and 11: Table Of ContentsFigure 3.4-12 Layo
Page 13: ALOS Data Users HandbookSection 1 I
Page 16 and 17: Section 2 ALOS Missionphotovoltaic-
Page 18 and 19: Section 2 ALOS Missiontrial fabrica
Page 20 and 21: Section 3 Outline of ALOS Satellite
Page 70 and 71: Section 4 Overview of ALOS Mission
Page 72 and 73: Section 4 Overview of ALOS Mission
Page 75 and 76: ALOS Data Users HandbookSection 5 A
Page 77 and 78: ALOS Data Users Handbook5.3 Operati
Page 79 and 80: ALOS Data Users HandbookBecause CH1
Page 81 and 82: ALOS Data Users Handbook240Mbps rec
Page 83 and 84: ALOS Data Users HandbookDRTS.As a c
Page 85 and 86: ALOS Data Users HandbookIn this met
Page 87: ALOS Data Users HandbookTable 5.8-1
Page 90 and 91: Section 6 ALOS Data Productsnumber
Page 92 and 93: Section 6 ALOS Data Products6.1.3 P
Page 94 and 95: Section 6 ALOS Data ProductsFigure
Page 96 and 97:
Section 6 ALOS Data ProductsTable 6
Page 98 and 99:
Section 6 ALOS Data Products6.2.4 P
Page 100 and 101:
Section 6 ALOS Data Products6.3.3 P
Page 102 and 103:
Section 6 ALOS Data ProductsTable 6
Page 104 and 105:
Section 7 Overview of Processing Al
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
Page 112 and 113:
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 126 and 127:
Page 128 and 129:
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 137 and 138:
ALOS Data Users HandbookSection 8 D
Page 139 and 140:
ALOS Data Users Handbook8.5 Outline
Page 141 and 142:
ALOS Data Users HandbookALOS Centra
Page 143 and 144:
ALOS Data Users HandbookWith respec
Page 145 and 146:
ALOS Data Users Handbook8.7 AUIG8.7
Page 147 and 148:
ALOS Data Users HandbookFigure 8.7-
Page 149 and 150:
ALOS Data Users Handbook8.7.3 NOTES
Page 151:
APPENDIXALOS Data Users Handbook
Page 154 and 155:
Appendix 1 Acronyms and Abbreviatio
Page 157 and 158:
ALOS Data Users HandbookAppendix 2
show all

ALOS Data Users Handbook

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?