Re: [gpsd-users] STATUS_DGPS_FIX mystery

[Roger Oberholtzer]

> From: Eric S. Raymond address@hidden
>> Gary E. Miller <address@hidden>:

>> Eric, any reason for this commit?  Looks like a step backwards.  I
>> would like STATUS_DGPS_FIX restored.

> Why? What you really want to know in practuce is the XYZ %95 error , no?

We use the gpsd shared memory segment to access current gps information. 
Previously we were parsing the NMEA strings ourselves. In our measurement 
systems, the operators are instructed to monitor the status. We use receivers 
that should be in DGPS mode during data collection. If they are not, the 
operator needs to figure out what is wrong. And decide if not being in DGPS is 
constant or intermittent. When measuring way up in northern Sweden in tree 
canyons, this is relevant information. While this may not be the most robust 
test one can do, our years of experience have led us to think that it is a 
useful metric of quality.

It seems odd to me to hide information that the GPS is providing.

If I connect a GPS receiver that does not indicate DGPS mode, then I should not 
be surprised if gpsd does not report that mode. OTOH, if I hook up a receiver 
that goes to all the trouble to report DGPS mode and gpsd does not report it, I 
think it would be correct to be confused. How is it possible, with such a 
receiver, to determine that the GPS is using DGPS?


Roger Oberholtzer

RST Systems

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