Two WAAS Sats cease signal-in-space (SIS) transmission on July 30th, 2007

[+PDOP's]

From the FAA (link)

 

INMARSAT AOR-W satellite (PRN # 122) and POR satellite (PRN #134) to be phased out

 

July 2007 (Update) - The Atlantic Ocean Region - West (AOR-W) satellite represented by PRN #122 and the Pacific Ocean Region (POR) satellite represented by PRN #134 will cease WAAS signal-in-space (SIS) transmission on July 30th, 2007.

 

and confirmed at http://www.nstb.tc.faa.gov/RT_WaasSatelliteStatus.htm

 

PRN #122 = Garmin 35 and PRN #134 = Garmin 47

[+Miragee]

But . . . what . . . does . . . it . . . mean?

 

[+EraSeek]

Basically, they were leased, and the lease is up. We are back to 2 WAAS. We have lost redundancy.

 

At least both 48 and 51 cover all of the US area:

Edited August 3, 2007 by EraSeek

[+PDOP's]

Just a note to add that I fired up my old GPS76 tonight and after a short while (I'm assuming to load the new almanac) it is now picking up 48 and 51. I had thought that a firmware upgrade might be required but it appears not.

[+Jim W]

Both 35, and 47 are getting old

 

[+tec_64]

Speaking of almanacs, how long does it usually take to load?

The data rate is 50 baud, is it not?

 

tec_64

[+PDOP's]

"Hold the unit until the full Almanac gets loaded. This will be indicated by the satellite(s) assuming the correct position on the page and will usually turn solid (but this is not a requirement). The figure on the right shows two GEO SV's in position from a location in California. When the satellite is in position and collecting data it will also begin working by starting to display small D's on the other satellite bars to indicate that they are in differential mode. It can take up to 5 minutes to load the almanac data and if it misses any of the data you could wait another 5 minutes for it to come around again. "(link)

Edited August 18, 2007 by PDOP's

[+tec_64]

Thanks for the verification and the link, PDOP's.

 

I see the D's on my Garmin. My Maggy display is a bit different.

 

tec_64

(VE3THN)

Sudbury, Ontario

[+Airmapper]

I've noticed my older Lowrance acting a little goofy with the change. I has been taking it a long time to cycle through and find 138. It will recall it as long as you don't take out the batteries, but take them out and it will have to start over. When I did a quick test perhaps I didn't allow enough time for it to fully load the almanac. It won't be long till I need to change the batteries, so I'll know soon.

[+EraSeek]

Concerning the rangeing of WAAS sat 48 and 51. 48 is set to Non-monitored at present and 51 is set to Non- precision. As the year wears on 48 will also become Non-precision, and then both will progress to Precision Approach near the end of 2007.

 

Rangeing is where the WAAS sats can function as a regular GPS sat in the position solution.