[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [gpsd-users] HDOP and fix mode in the python library
|
From: |
Gary E. Miller |
|
Subject: |
Re: [gpsd-users] HDOP and fix mode in the python library |
|
Date: |
Wed, 2 Aug 2017 11:18:19 -0700 |
Yo Fabián!
On Wed, 2 Aug 2017 03:16:20 -0400
Fabián Inostroza <address@hidden> wrote:
> I'm using a SIM5320A 3G+GPS module.
I see nothing in the SIM5320A datasheet about GPS:
https://cdn-shop.adafruit.com/datasheets/SIM5320_Specification_V1202.PDF
Can you be more specific?
> 1. When the fix is lost, the mode given by the python library
> doesn't get updated, so it is useless.
gpsd only passes on data when it gets data. Are you saying that
gpsd is getting a 'fix lost' message from your GPS, bit not passing it
on? Or does the GPS not report NO FIX status?
> 2. Because of (1) I have to use hdop and satellites used to
> determine if the fix is acceptable but when the fix is lost the GPS
> outputs empty hdop, vdop and pdop and keeps outputting satellite
> data. In this situation gpsd uses that information to calculate the
> dilituion values, this sometimes gives very good hdop values but the
> position is completely wrong.
gpsd calculates xDOP internally since so few GPS do it, and do it
properly.
Are you saying your GPS does not send gpsd a flag on whether it has
NO FIX. 2D FIX, or 3D FIX?
> 3. When the GPS is stationary it gives
> an empty heading value but gpsd interprets it as 0
Meaningless either way, since the GPS is stationary.
> Note that cgps produces the same results.
As expected.
> Is there a way to disable the hdop calculation done by gpsd without
> recompiling?,
No, but we could explore it as a new feature. But since the GPS is
outputting emtpy xDOPs that does not seem useful.
> I'm using gpsd 3.16 in an embedded ARM linux board and it is more or
> less difficult to recompile the package
Really? I recompile gpsd on ARM Linux sometimes dozens of times a day.
> I have attached a log of the nmea output without fix.
Can you provide a log both with and without fix as one continous
log?
RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
address@hidden Tel:+1 541 382 8588
Veritas liberabit vos. -- Quid est veritas?
"If you can’t measure it, you can’t improve it." - Lord Kelvin
pgpwU0hiTfP3B.pgp
Description: OpenPGP digital signature