Future NOAA Polar Orbiting and
Geostationary Satellite Systems

During this decade, through 2010, substantial changes will be made to the NOAA constellation of polar orbiting and geostationary satellites. These changes are being implemented to take advantage of new technologies, the requirements for additional and different data, and the need to achieve a cost effective United States environmental satellite program.

GOES WEFAX

The change that will occur most immediately will be the replacement of the GOES analog WEFAX transmission service with the digital Low Rate Information Transmission (LRIT) during the period 2003 to 2005. During 2003, test LRIT transmissions will be made from the GOES-East (GOES-12) satellite. During 2004, a regular schedule of alternating analog WEFAX and digital LRIT transmissions will be made each hour. By early 2005, it is expected NOAA will have completed this transitiion and WEFAX will no longer be transmitted from the NOAA GOES satellites.

While LRIT will continue to be transmitted on the 1691.0 Mhz frequency, users will need to upgrade or replace both receiving hardware and processing software to utilize LRIT. LRIT will become the worldwide standard for the low data rate image transmission service from geostationary satellites by all meteorological/environmental satellite operators during the next several years.

NOAA will follow the global specification for LRIT as agreed to by the nations operating meteorological satellite systems. There may be regional differences in the NOAA LRIT transmission, but these will be managed in software rather than hardware. NOAA has released it general hardware specifications as well as the source code for processing the LRIT data stream to manufacturers for the development of LRIT receivers. For further information and documentation on NOAA LRIT transition plans, refer to the LRIT web site.

NOAA APT

The European METOP satellite, to be launched at the end of 2005, will introduce the digital replacement for APT, called LRPT (Low Rate Picture Transmission). LRPT will continue to operate in the same VHF band as the present APT service on NOAA satellites, but will require new hardware and software to receive and process the digital data.

NOAA still has NOAA-18 and NOAA-19 yet to be launched, and both those will will still carry APT (See launch schedule). However, the transmission frequencies will change to 137.1 MHz (lower) and 137.9125 MHz (upper).

Based on the typical life expectancy of the satellites, we would expect APT will be available on at least one NOAA satellite until about 2010. APT will no longer be available on NOAA satellites after NOAA-19, and will be replaced by digital services on the next generation NPOESS satellites expected to be launched beginning in 2009.