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The Return of SVN49
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Sam Wormley
Feb 1, 2012, 7:23:21 PM2/1/12
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> The Return of SVN49
> Inside GNSS
> 27 January 2012
>
> In the U.S. Air Force's transmitting an L-band signal next week to continue exploring
> options for its regular operation. However, the signal will not be considered usable or
> "healthy" nor included in the broadcast almanac.
>
> A Notice Advisory to NAVSTAR Users (NANU) issued today (January 27, 2012), states, "On
> approximately 01 FEB 2012 SVN49 will resume transmitting L-band utilizing PRN24. At L-band
> activation, SVN49/PRN24 will be unusable until further notice. Additionally, no broadcast
> almanacs will include SVN49/PRN24. Future NANUs will inform users of any changes to the
> above-stated status." The GPS constellation is managed by the USAF 2nd Space Operations
> Squadron (2 SOPS) at Schriever Air Force Base, Colorado.
>
> Signals from the satellite have been unusuable since shortly after its March 24, 2009, as
> a result of signal reflections coming from a special auxiliary port (designated J2) that
> is used to feed the L5 signal to the satellite's antenna array. These reflections cause a
> secondary-path signal with a delay of approximately 30 nanoseconds, which has the
> appearance of a multipath error to many GPS receivers. The problem appears most strongly
> on signals transmitted on the L1 frequency.
> Inside GNSS
> 27 January 2012
>
> In the U.S. Air Force's transmitting an L-band signal next week to continue exploring
> options for its regular operation. However, the signal will not be considered usable or
> "healthy" nor included in the broadcast almanac.
>
> A Notice Advisory to NAVSTAR Users (NANU) issued today (January 27, 2012), states, "On
> approximately 01 FEB 2012 SVN49 will resume transmitting L-band utilizing PRN24. At L-band
> activation, SVN49/PRN24 will be unusable until further notice. Additionally, no broadcast
> almanacs will include SVN49/PRN24. Future NANUs will inform users of any changes to the
> above-stated status." The GPS constellation is managed by the USAF 2nd Space Operations
> Squadron (2 SOPS) at Schriever Air Force Base, Colorado.
>
> Signals from the satellite have been unusuable since shortly after its March 24, 2009, as
> a result of signal reflections coming from a special auxiliary port (designated J2) that
> is used to feed the L5 signal to the satellite's antenna array. These reflections cause a
> secondary-path signal with a delay of approximately 30 nanoseconds, which has the
> appearance of a multipath error to many GPS receivers. The problem appears most strongly
> on signals transmitted on the L1 frequency.
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