1 International EOS/NPP International EOS/NPP Direct Readout Meeting Direct Readout Meeting October 2005 October 2005 National Polar-orbiting National Polar-orbiting Operational Environmental Operational Environmental Satellite System Satellite System (NPOESS) (NPOESS) Direct Readout Mission Direct Readout Mission
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1 International EOS/NPP Direct Readout Meeting October 2005 National Polar-orbiting Operational Environmental Satellite System (NPOESS) Direct Readout.
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International EOS/NPP International EOS/NPP Direct Readout MeetingDirect Readout Meeting
October 2005October 2005
National Polar-orbiting Operational National Polar-orbiting Operational Environmental Satellite SystemEnvironmental Satellite System
NPOESS Satisfies Evolutionary Program Needs with Enhanced CapabilitiesNPOESS Satisfies Evolutionary Program Needs with Enhanced CapabilitiesNPOESS Satisfies Evolutionary Program Needs with Enhanced CapabilitiesNPOESS Satisfies Evolutionary Program Needs with Enhanced Capabilities
Parameter Value/CharacteristicData Format NRZ-M (Prior to convolutional encoding)
Reed-Solomon Coding (255, 223) with Interleave Depth = 4
Convolution Coding:
- Coding Rate (R)
- Constraint Length
- Connection Vectors
- Phase Relationship
- Symbol Inversion
- Number of Encoders
(CCSDS 101.0-B-6)
1/2
7
G1=1111001, G2=1011011
G1 symbol before G2 symbol
G2
1
Data Randomization:- Generator
(CCSDS 101.0-B-6)
h(x)=x8+x7+x5+x3+1
8
HRD EIRP vs. Nadir Angle
6789
10111213141516171819202122232425262728293031
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Nadir Angle (deg)
EIR
P (
dB
Wi)
PFD Limit
RF Comm Subsystem Spec
• Shaped beam antenna compensates for space & rain loss variation (function of ground antenna elevation angle) to provide near constant PFD at surface of Earth
Parameter Value/CharacteristicData Format NRZ-M (Prior to convolutional encoding)
Reed-Solomon Coding (255, 223) with Interleave Depth = 4
Convolution Coding:
- Coding Rate (R)
- Constraint Length
- Connection Vectors
- Phase Relationship
- Symbol Inversion
- Number of Encoders
(CCSDS 101.0-B-6)
1/2
7
G1=1111001, G2=1011011
G1 symbol before G2 symbol
G2
1
Data Randomization:- Generator
(CCSDS 101.0-B-6)
h(x)=x8+x7+x5+x3+1
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LRD EIRP vs. Nadir Angle
• Shaped beam antenna compensates for space and rain loss Variation (function of ground antenna elevation angle) to provide near constant PFD at surface of Earth
LRD Data Content Balances Performance and Provides Flexibility
Limited LRD Bandwidth
3.88 Mbps
Programmable LRD downlink Programmable LRD downlink provides flexibility for the futureprovides flexibility for the futureProgrammable LRD downlink Programmable LRD downlink
provides flexibility for the futureprovides flexibility for the future
1330 & 1730 2130
-
500,000
1,000,000
1,500,000
2,000,000
2,500,000
3,000,000
3,500,000
4,000,000
1 2 3 4
VIIRS**
CMIS*
CrIS*
ATMS*
Margin
Ancillary*
ALT
ADCS
DMDM
TOD
Encryption
CCSDS-
500,000
1,000,000
1,500,000
2,000,000
2,500,000
3,000,000
3,500,000
4,000,000
1 2 3 4
CrIS
CMIS
VIIRS
Selection of compression (6:1) applied to selected VIIRS mission data for increased mission data throughput in downlink
-
500,000
1,000,000
1,500,000
2,000,000
2,500,000
3,000,000
3,500,000
4,000,000
1 2 3 4
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Field Terminal Ancillary Data Approach
Dynamic ancillary data contained within LRD and HRD downlinks to meet specified performance levels
Data for six pressure levels from the NWP forecast model - Temperature- Humidity- Surface pressure- Standard pressure levels- Wind speed, wind direction- Precipitable water
For SESS EDR production• Effective sunspot number and global geomagnetic Kp
NPOESS mission support data server, accessible via internet
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Ancillary Data DownlinkGraphical Representations
• 16 points spaced 200 kilometers apart at right angles to the ground track
• Completely covers the area viewed by all sensors
• Successive lines 200 kilometers apart
• Each line transmitted twice to ensure receipt by the ground
Path of the satellite
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21
EDRs with Key Performance Parameters
VIIRSCMISCrIS/ATMSOMPSSESGPSOSERBSTSISALTAPS
2519
31
1325134
NPOESS High Rate Data (HRD)Environmental Data Records (EDRs)
- Mission Data- Mission Support Data- Satellite Pass Storage- TLE Extraction
• Decryption
FT Operator
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Field Terminal Data Processor Element Software Design
•Open Systems Group standards compliance at interfaces minimizes configurations
•Programmable LRD downlink favors 8 Priority EDRs
•Onboard VIIRS data compression rates by APID for LRD
•Flexible ancillary data approach • Dynamic ancillary data via satellite downlink • NPOESS Mission Support Data Server via Internet access
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FTS EDR Performance
HRD EDR performance• 99% of performance attributes meet or exceed performance
thresholds• Latency requirements achievable with current COTS multiple
CPU workstations • Designed to recognize missing channels and ancillary data• Lossless RICE compression on VIIRS
LRD EDR performance• 0.8 km resolution imagery and programmable downlink• Produces 8 high priority EDRs at or near LRD objective levels• Produces 15 lower priority EDRs and required predecessor
EDRs• Designed to recognize missing channels and ancillary data• Lossless and Lossy JPEG2000 compression on selected APIDs
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FTS Latency Analysis for Stress-case
• FTS Latency Requirement: max latency is 15 minutes. • SYS013235 & SYS013230 - Field Terminal software, when installed on NPOESS-
specified HRD field terminal hardware, shall produce the Imagery EDR in less than or equal to 2 minutes and all other EDRs as specified in Appendix E in less than or equal to 15 minutes after receipt of data from the FT Signal Processing Subsystem.
• A large number of factors impact FTS processing. • Terrain - Land or ocean• Day versus Night sensor characteristics• Weather - Cloudy, Partial Cloudy, Clear• Satellite Orbits & FTS emplacement (Latitudes)• FTS Hardware: CPUs (3 GHz NPP era)
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FTS Simulation (e.g. 45N/00):1 day 15 Passes with 3 NPOESS S/C
Overlapping S/C contacts don’t occur due to spacecraft orbital phasing.
Smallest gap of 10.2 minutes has minimal impact to FTS latency.
Above 60N there is a large increase in contacts and EDRs.
Back-to-back S/C Contacts
Max gap is 2.1 orbits at equator
Gap Time Between Contacts
Analyzed STK 1330/1730/2130 contact data
60N
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Orbital Position Defines Dynamic Scene Content in Sensor Data
Orbital Position defines Sensor Nadir NCEP Weather Data Base
Scene in VIIRS View
Ocean
Cloudy
Snow/Ice
Dynamic Processing
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Land/Ocean, Day/Night, and Clear/Cloudy Data
Land has process loads comparable to ocean.
Day data is 4x night data processing. Day-only algorithms are: • ACO/OCC • Vegetation Index • Surface Types• Aerosols (large load)• Surface Albedo (large load)
Clear Data is most stressing Clear-only algorithms are: • ACO/OCC • Vegetation Index • Land/Ice Surface & Sea Surface Temp• Surface Types• Aerosols (large load)• Surface Albedo (large load)• CMIS/CrIS AVT/MP (large load)
Direct Readout Mission POCs: • John Overton: (301) 713-4747• Bill Munley: (301) 713-4782• Joe Mulligan: (301) 713-4803• John van de Wouw: (310) 812-0800