89th American Meteorological Society Annual Meeting

Tuesday, 13 January 2009
NPOESS' Key to Low Data Latency: SafetyNetTM
Hall 5 (Phoenix Convention Center)
David G. Lubar, Raytheon Intelligence and Information Systems, Aurora, CO; and G. Cook and M. L. Jamilkowski
A key feature of the National Polar-orbiting Operational Environmental Satellite System (NPOESS) is the Northrop Grumman Space Technology patent-pending data collection architecture known as ‘SafetyNetTM‘. The centerpiece of SafetyNetTM is the system of fifteen globally-distributed ground receptors developed by Raytheon Company. These receptors or antennae will collect up to five times as much environmental data approxi-mately four times faster than current polar-orbiting weather satellites. Once collected, these data will be forwarded near-instantaneously to U.S. weather centrals via global fiber optic network for processing and production of data records for use in environmental prediction models.

Key system design factors:

The NPOESS SafetyNetTM architecture provides:

o Frequent downlinks and maximizes contact duration (>100% margin) at low cost,

o Downlink bandwidth margin that allows all Stored Mission Data to be down linked to two separate receptors and

o Minimal latency impacts from loss of multiple ground receptors.

Other notable characteristics of SafetyNetTM:

o Simple, receive-only, Ka Band receptor design provides autonomous operations

o Fifteen locations in ten countries; full-motion to track polar satellites

o Reliable and timely collection, delivery and processing of quality data

o 75% of NPOESS data products delivered to the US's weather centrals within 15 minutes; the rest in under 30 minutes

Presentation will show:

• A graphic of SafetyNetTM within the NPOESS program architecture

• A depiction of the NPOESS data download scheme

• A map of the worldwide SafetyNetTM receptor locations

• A graph of the percent of NPOESS Environmental Data Records (EDRs) versus time from observation to delivery

• A example chart of the NPOESS data downlink patterns to SafetyNetTM receptors

• Example photos of SafetyNetTM receptor antennae and radomes

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