Re: SiRF receivers
Ralph Wallio, W0RPK <wallio@...>
Bill,toggle quoted messageShow quoted text
Use of SiRFStar chipsets above 60kft is being discussed because AXIOM
Sandpiper receivers are appearing on the inexpensive surplus market. I have
evaluated a pair of these receivers for terrestrial applications, e.g.,
APRS, and find documentation and PC software to be readily available.
Michael Castle has further contributed his knowledge that SiRF code will
allow receivers based on SiRFStar-II chipsets to work above 60kft when
velocity is <1000kts. However, the AXIOM Sandpiper receiver uses the
SiRFStar-I chipset which Michael had not yet completely investigated. Your
empirical evidence appears to definitively tell us that code in the
SiRFStar-I chipset limits performance to altitudes below 60kt regardless of
vehicle velocity and acceleration.
All models of AXIOM Swift receivers use SiRFStar-II chipsets so Michael's
contribution is valuable.
Please compile and forward detailed information required for an AXIOM
Sandpiper entry to http://users.crosspaths.net/~wallio/gps60kft.html and I
will add it to the RED list.
For comparison, this what I see when my Sandpiper receivers come up:
SiRF Baseline Version: 1.3.1DKIT144 Axiom Variant: k201AX
Build date: Nov 12 1999
$Build time: 14:42:07
TNX es 73 de Ralph Wallio, W0RPK
Results may not be reproducible
----- Original Message -----
Sent: Friday, June 07, 2002 0:19 AM
Subject: Re: [GPSL] Re: SiRF receivers
just like the Motorola VP Oncore would...i.e. as long as you didn't exceed60k
would not be a problem. Some receivers will lock up at 60k feet regardlessof
the speed travelled, it depends on the manufacturer. I know that the VPSee
any more flights with the Axiom units, although I may try an experimentusing
the very tiny Swift model Axiom receiver that I have as a backup GPS tosee
if it works above 60k.