Re: [gpsd-dev] [PATCH 5/9] Define TTFF

[Sanjeev Gupta]

On Sat, Apr 18, 2015 at 4:21 AM, Gary E. Miller <address@hidden> wrote:

> WIthout an almanac... any almanac, often including expired ones, the
> receiver cannot do more than open its correlator and attempt to snag
> onto a spreading signal with a recognizable Gold-code. Then it can
> start receiving data.

Which with a 66 channel receiver is not a big deal.  Just try them
all at once.

Please see:  http://bit.ly/1ITXBPt  (URL shortened, goes to Google Books)

Sec 3.3.3

The section seems to describe how a modern (2009) receiver brute-forces, in parallel, the entire constellation, and needs no almanac a priori.

May I suggest that my $25 receiver outperforms the best that Gerry could get the NOAA to buy, or Eric could dream of, when this documentation was written?

We still need to define these terms, if for no other than that reason so that people like me can drift into the project, but increasing receiver sensitivity and multi-channel design mean that the users of gpsd will never be able to see, or use, these distinctions.

--
Sanjeev Gupta
+65 98551208     http://www.linkedin.com/in/ghane