[hpsdr] Fwd: 1, 2, 3, 4, 5, 6, 7....

[Mike]

The 100 ft CEP seems like a huge amount when seen from the front left seat
of an aircraft, especially one that is certified for 0/0 landing.
Yes, we use other devices for landing / touchdown. I'm just saying...

Mike G. 


> -----Original Message-----
> From: hpsdr-bounces at lists.openhpsdr.org [mailto:hpsdr-
> bounces at lists.openhpsdr.org] On Behalf Of Glenn Thomas
> Sent: Thursday, July 26, 2012 9:39 AM
> To: hpsdr at lists.openhpsdr.org
> Subject: Re: [hpsdr] Fwd: 1, 2, 3, 4, 5, 6, 7....
> 
> ***** High Performance Software Defined Radio Discussion List *****
> 
> Also, keep in mind that the GPS system specification calls for a C/A
solution
> accuracy of about 100' CEP. In the lat & long, that doesn't seem like very
much,
> however we seem to be a bit more sensitive about altitude. - Glenn
> 
> On 7/26/2012 8:25 AM, John Ackermann N8UR wrote:
> > ***** High Performance Software Defined Radio Discussion List *****
> >
> > I don't know if that's true (you may be thinking of the old Selective
> > Availability, which was turned off quite a while ago). As I understand
> > it, the main issue is that the geometry of the satellites just doesn't
> > allow as precise a fix of altitude as it does the other axes.
> >
> > To get best accuracy in altitude, you'd like a fix that includes
> > reference points both above and below your location.  But the GPS
> > can't see satellites that are below the horizon, so the quality of the
> > fix suffers.
> >
> > John
> >
> > On 7/26/2012 11:15 AM, Tim O'Rourke wrote:
> >> ***** High Performance Software Defined Radio Discussion List *****
> >>
> >>
> >>
> >> US goverment keeps some of GPS altidude capability vauge for security
> >> purposes.
> >>
> >>
> >>     -----Original Message-----
> >>     From: Alberto I2PHD
> >>     Sent: Jul 26, 2012 10:58 AM
> >>     To: HPSDR list
> >>     Subject: Re: [hpsdr] Fwd: 1, 2, 3, 4, 5, 6, 7....
> >>
> >>     On 7/26/2012 1:42 PM, Simon HB9DRV wrote:
> >>>
> >>>     I have a Thunderbolt on my balcony; using Lady heather I can
> >>>     confirm that my house hasn't moved by more than a few cms in the
> >>>     last year J
> >>>
> >>     Have you checked the altitude too ? My Thunderbolt tells me that
> >>     from the morning to the evening of the same day
> >>     my house moved up and down by almost 30 meters.... :-)   and the
> >>     antenna is firmly attached to one of the chimneys....
> >>
> >>     I guess that is one of the reasons why GPS is not used on any
> >>     aircraft, at least as an altitude measuring device...
> >>
> >>     --
> >>     /*73 Alberto I2PHD*/
> >>
> >>
> >> Tim O'Rourke
> >> W4YN at ARRL.Net
> >> Low Power Amateur Radio Rocks
> >> Member of Flying Pigs,ARCI,GQRP,RSGB,ARRL Life Member NHRA Life
> >> Member
> >>
> >>
> >>
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