This enhancement effectively extends the geographical coverage of the AHRPT service to parts of Africa, Asia and the Pacific region where previously users were unable to receive the service. For the first time since the start of zone-based operations, transmissions will take place over ascending portions of the orbit, thereby further benefiting currently served geographic zones. Figure 1 below indicates the new coverage zones for both descending and ascending passes. For spacecraft safety reasons, the service still maintains the same operational restrictions when passing over the polar regions and South Atlantic Anomaly.

Figure 1: Metop-A AHRPT Switch-on Zone - effective as of 18 January 2011 as a pre-operational service (Click to enlarge)

The extended service will commence with a pre-operational phase and is expected to be fully operational as of 18 February 2011.  The new AHRPT switch-on and switch-off times are provided in the User Notification Service (UNS) Metop ADMIN Message.

Following the earlier failure of the Metop-A AHRPT due to heavy ion radiation at certain points of the Metop orbit, namely towards polar regions and South Atlantic Anomaly, the AHRPT service is operated within predetermined geographical boundaries to minimise the risk of failure on the remaining AHRPT unit. These boundaries are now being extended to improve the service to users.

For further information, see our Direct Readout Service page, or contact our User Service Helpdesk.

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