|
|
|
|
|||||
|
||||||
From: Jim Donohue (no email)
Date: Mon Jun 30 2003 - 01:13:59 EDT
I think I have this down reasonably well conceptually Arild...I don't do
engineering in the area so I don't want to push my understanding too hard.
Basically you stick a simulator of a satellite at a fixed location. It
gives out proper sentences in the proper format encoded properly so it looks
to the receiver like a satellite. It is in fact a lump sitting on some
local promontory. So what the receiver has is something that transmits a
signal that looks just like a satellite but is just down the block a bit.
With a little cheating you can get a receiver to favor this particular class
of vector.
To the receiver it is a satellite...just one close in and maybe one it gives
high weight to.
The geosynchronous satellites don't care where anything is...they just get
into geometric problems in the far north.. If there is a high hill to the
south you may not be able to see the satellite to get the corrections. You
could also play the same game with LEOs though I don't know if this is
practical.
For WAAS to hit its full potential requires reference stations everywhere.
Reading between the lines though it is not a concensus position in the US
government...The CG and others are putting up other possible approaches. ie
differential stations everywhere all coupled. Phase 2 you start correcting
the numbers between the stations. In the end game we have two systems that
tell you where you are precisely...then maybe the europeans through in a
third or third and fourth.. who knows may end up with a product that judges
who has the best fix in the particular area.
Jim
> -----Original Message-----
> From:
> [mailto:]On Behalf Of Arild
> Jensen
> Sent: Monday, June 30, 2003 9:21 PM
> To:
> Cc:
> Subject: TWL: RE: RE: WAAS or Not To WAAS
>
>
> -----Original Message-----
>
> REPLY
>
> Okay so exactly what is a pseudo satellite and how does it differ from a
> receiver used for differential corrections.
>
> To Unsubscribe send email to
> Include the word "Unsubscribe" (and nothing else) in the subject
> or body of the message.
>
>
_______________________________________________
http://lists.samurai.com/mailman/listinfo/trawler-world-list
To Unsubscribe send email to
Include the word "Unsubscribe" (and nothing else) in the subject or body of the message.
|