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Re: [gpsd-dev] Another query on terminology


From: Gerry Creager - NOAA Affiliate
Subject: Re: [gpsd-dev] Another query on terminology
Date: Tue, 7 Apr 2015 13:26:13 -0500

As the guy who has little time, hasn't contributed any code to gpsd in recent history, but has spent a little time working with GNSS, and especially GPS, I'll take the position that #1 is a better choice. 

GPS is a system, although you can say NavStar if you'd like. NavStar GPS dates back a few years, and in general, at the USAF level, has been dropped. GNSS is a system-wide designator, however. GPS refers to a specific constellation of related space vehicles, in a common constellation configuration, just as GLONASS, BeiDou, and Galileo do. 

Since the project is "gpsd" I can understand the thinking that GPS is generic... but I believe it's incorrect. GPS is a specific system. 

gerry

On Tue, Apr 7, 2015 at 12:42 PM, Eric S. Raymond <address@hidden> wrote:
Sanjeev Gupta <address@hidden>:
> Eric,
>
> In some document (eg www/NMEA.txt)  we say:
>
> "
> a. GPS satellites are identified by their PRN numbers, which range from 1
> to 32.
> "
> which implies that "GPS" is the US-specific constellation.  The other
> constellations are referred to by name (GLONASS, BeiDou, etc).  The term
> "GNSS" does not appear.
>
> In other documents (www/hacking.html.in) we seem to use the term GNSS as
> complementary: "The GPS/GNSS monitoring tools"
>
>
> In drivers.c , I see:
> :
> 3  NMEA_SEN_GGA,  GPGGA   interval - GPS Fix Data
> 4  NMEA_SEN_GSA,  GPGSA   interval - GNSS DOPS and Active Satellites
> 5  NMEA_SEN_GSV,  GPGSV   interval - GNSS Satellites in View
> 6  NMEA_SEN_GRS,  GPGRS   interval - GNSS Range Residuals
> 7  NMEA_SEN_GST,  GPGST   interval - GNSS Pseudorange Errors Statistics
> 13 NMEA_SEN_MALM, PMTKALM interval - GPS almanac information
> "
> which seems to be mixing up stuff.
>
> Suggestion: we use either one of:
>
>    1. GNSS as a generic, and GPS, GLONASS, BeiDou as systems
>    2. GPS as generic, and Navstar, GLONASS, BeiDou as systems
>
> Once you take this decision, I believe it will hep clarify the PRN issue a
> little as well.  This will not impact code, just the documentation.
> --
> Sanjeev Gupta
> +65 98551208     http://www.linkedin.com/in/ghane

I've been thinking about this as well.  Let's go with 2, it will confuse
most people less I think.  Go ahead and patch this.  Include definition
of "Navstar" where appropriate, and mention the ambiguity of "GPS".
--
                <a href="" href="http://www.catb.org/~esr/" target="_blank">http://www.catb.org/~esr/">Eric S. Raymond</a>




--
Gerry Creager
NSSL/CIMMS
405.325.6371
++++++++++++++++++++++
“Big whorls have little whorls,
That feed on their velocity; 
And little whorls have lesser whorls, 
And so on to viscosity.” 
Lewis Fry Richardson (1881-1953)

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