[ntp:questions] YEA! My Sure Electronics GPS just arrived.
Ron Frazier (NTP)
timekeepingntplist at c3energy.com
Sat Mar 24 01:50:20 UTC 2012
On 3/23/2012 7:31 PM, unruh wrote:
> On 2012-03-23, Ron Frazier (NTP)<timekeepingntplist at c3energy.com> wrote:
>> Hi all,
>> YEA! My Sure Electronics GPS just arrived. I ordered on 03/05/12 and
>> it arrived on 03/23/12, so it took 18 days.
> Yes, you pay for the cheapness by slowness. Note that you want to keep
> eyes on the antenna. If you find your sure blue light stop flashing you
> probably have a defective antenna.
>> My configuration is:
>> GPS USB port --> PC 2nd USB port - for power only
>> GPS serial port --> Trendnet TU-S9 (Prolific based) serial - USB adapter
>> --> PC 1st USB port (same as I had the BU-353 on)
>> GPS antenna port --> included antenna
>> Using Terje's NMEA-MTK program, I sent the commands to the unit to
>> engage WAAS, send only GPGGA, and change the baud rate to 57600 as follows.
>> You can get help from the program as follows:
>> nmea-mtk /?
>> The board was already at 9600 baud transmitting several sentences.
>> I sent this command to enable WAAS and set for GPGGA sentences only (the
>> default action):
>> nmea-mtk -p \\.\COM5
>> I verified that it's working with SirfDemo. This is OK as long as I
>> don't send any commands from SirfDemo and use it for display only. I
>> set the SirfDemo data source for COM5 at 9600 baud, connected to the
>> GPS, and observed the NMEA data sentences. Then I disconnected SirfDemo.
>> I sent this to change baud rate to 57600:
>> nmea-mtk -p \\.\COM5 -c PMTK251,57600
>> I verified that it's working with this command. Now I have to send the
>> new baud rate in the command so nmea-mtk will read the port and match
>> the baud rate of the GPS. This reads out NMEA data for 10 seconds.
>> nmea-mtk -p \\.\COM5 -b 57600 -t 10
>> I also verified that it's working with SirfDemo after settings its baud
>> rate for the data source to 57600.
>> At the moment, I'm using NMEA only through the serial port of the GPS.
>> I haven't tried NMEA through the GPS's USB port, but I assume it would
>> be similar, since, either way, I'm going though a serial - USB
> Why would you do that when the Sure board already sends USB nmea data on
> the usb port.
As far as I know, the only way I can get PPS into the PC is with the
serial port through the DCD pin, which I have to wire up. So, I just
decided to connect right up to the serial port. However, if that PPS
signal is shipped through the board's USB interface, that would be
great. Anyone know if that's the case?
>> converter. The Sure board uses a CP2102 usb to uart chipset, whatever
>> that is, but I never loaded the driver for it. Since my external TU-s9
>> adapter uses the same Prolific driver that the BU-353 GPS did, I'm just
>> using that. I am currently testing in Windows.
>> Preliminary graphs indicate I'm getting a variance of + / - 25 ms from
>> my PC's clock to the GPS polling it every 8 sec. That's a bit
>> disappointing, since I was getting + / - 10 ms from the BU-353 going
>> through it's internal serial - USB converter. I'm going to monitor it
>> for about a week and see how stable it is relative to the internet
>> servers. Also, I'm hoping it doesn't have periodic heart attacks like
>> the BU-353 did. I am testing indoors, as before.
>> I have a question for someone with experience with the board. If I
>> unplug the board, will it retain it's programming, or will it lose it?
>> If it retains it, how long will it keep the data? If it loses it, how
>> can I prevent that?
> It keeps its programming forever. It keeps its current solution for I
> think about an hour using the onboard capacitor. But it does not take
> very long to aquire a new solution and start delivering the time to far
> higher accuracy than you need (something like a couple of minutes)
> questions mailing list
> questions at lists.ntp.org
(PS - If you email me and don't get a quick response, don't be concerned.
I get about 300 emails per day from alternate energy mailing lists and
such. I don't always see new messages very quickly. If you need a
reply and have not heard from me in 1 - 2 weeks, send your message again.)
timekeepingdude AT c3energy.com
More information about the questions