On Tue, Apr 14, 2015 at 10:33 PM, Greg Troxel <address@hidden> wrote:
I think it's best to avoid intentionally misusing GPS in documentation.
It's fine to point out that this started in a world where GPS was the
primary/only GNSS, although LORAN speaking NMEA surely existed then.
I (partially) agree, which is why I added the line about how we were gpsd, not gnssd.
For this discussion, because we are addressing the meaning of "GPS", I will use Navstar to mean the ~30 bird constelation run by 2SPOPS.
While I agree that GPS is used popularly to refer to multiple
constellations, I hold that such usage is incorrect, does not aid
claity, and should not be propagated in technical documentation.
Yes. And the code uses GPS == Navstar, implicitly or explicitly, all over.
As Eric pointed out, popular usage has diverged from technically correct usage (cf: hacker). So what do we do? And I keep correcting people who say "GMT", changing that to "UTC", this does not make me popular in seminars :-(
I am ambivalent, but I would like consistency in the documentation.
"Consistency is the hallmark of the unimaginative.”
―
Oscar Wilde
So I would change to GNSS when we mean any of the 4 systems or any
future similar system, and treat GPS as the proper name that it is,
referring the the US system, and acknowledge that in popular usage "GPS
receiver" is a device that definitely receives the US GPS signal and may
also receive other signals. Certainly no one would call a dual-system
GLONASS/Galileo receiver a "GPS receiver", or certainly they should not.
Over the last week, I have been communicating with a dozen people in China and Taiwan who (claim to) make or sell these devices, in my quest for a BeiDou receiver. And I can confirm that the data sheets use GPS to refer _only_ and consistently to the US Navstar.
I don't meant to suggest rototilling the code to change gps_ to gnss_.
:-)
Your 3 other patches look good. As a nit, while refraction is better
than reflection, it's also (mainly?) about propagation speed due to
moisture in the troposphere and ionization. So perhaps better to just
say "propagation times of the signals vary due to changing properties of
the troposphere and ionosphere"; the point of differential is that these
propagation time variances are measured and adjusted out.
Excellent, and thank you. I was not aware of the effect of moisture, all the people I spoke too had diagrams which looked like refraction because of varying density (only).
That said, gpsd should avoid going down the path of explaining how
GPS/GNSS works too far.
At some point, the amount of documentation files should be reduced, we have duplication, and this leads to changes not propagating fully. But that is for gpsd 4.0 :-)