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[DPRG] NMEA commands to configure a SiRFstarIII

Subject: [DPRG] NMEA commands to configure a SiRFstarIII
From: Kenneth Maxon kmaxon at qwest.net
Date: Tue Mar 25 19:47:33 CDT 2008


Nope, no miss-speaking going on.  I believe the confusion is that some new
SiRF-III modules like the one that I purchased boasts an 5-Hz update rate.
I *AM* pulling down data at 38400, it's native data rate, however I've not
checked the data to see if there are 5 update messages per second and if
they contain unique data..

-Kenneth



-----Original Message-----
From: dprglist-bounces at dprg.org [mailto:dprglist-bounces at dprg.org]On
Behalf Of Dean Hall
Sent: Tuesday, March 25, 2008 11:02 AM
To: dprglist
Subject: Re: [DPRG] NMEA commands to configure a SiRFstarIII


No, the GGA and RMC sentences still arrive at 1 Hz.  That's the
fastest that my SiRF module allows in NMEA mode.  Did I mis-speak/
type somewhere?

My robot has a 5 Hz sensor task and I plan to run the predictor-half
of the Kalman Filter at 5 Hz, but the corrector-half of the KF will
only be run when the NMEA sentence arrives (@ 1 Hz).

!!Dean

On Mar 25, 2008, at 11:10 , dpa wrote:
> Hi Dean,
>
> Very nice.  Thanks for the writeup.
>
> So with this arrangement you are getting gps position updates at 5Hz?
>
> dpa
>
>
> !!Dean wrote:
>> I did a quick write-up on how I use SiRF NMEA commands to configure
>> my GPS module to communicate at 19200 baud and only send the 2 NMEA
>> sentence types that I use for GPS data input to my robot.  Cutting
>> out the unused sentence types reduces the number of UART receive
>> interrupts by 69%!  This helps keep the CPU load down so I have
>> enough processing time for other tasks.
>>
>> http://deanandara.com/Argonaut/Sensors/Gps/
>> ConfiguringSirfStarIII.html
>>
>> Here's where I learned to do all this:
>> http://www.usglobalsat.com/downloads/NMEA_commands.pdf
>>
>> (This information only applies to SiRFstarIII chips)
>>
>>  !!Dean
>>
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