<div dir="ltr">Thanks for the info Christopher and Michael! I'll try it without resetting, and see if that helps. <div><br></div><div>-Arthur</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Nov 5, 2014 at 4:20 AM, Michael Balzer <span dir="ltr"><<a href="mailto:dexter@expeedo.de" target="_blank">dexter@expeedo.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
Hi Arthur,<br>
<br>
the SIM908 hardware design doc says:<br>
<blockquote><i>Power down mode: The GPS engine will be set into this
mode by sending AT command “AT+CGPSPWR=0”. In this mode the
internal power supply for GPS will be shutdown, and the current
consumption is very low. The last position, current time and
ephemeris data will be stored in the GSM host memory.</i><br>
</blockquote>
...and...<br>
<blockquote><i>User can power on GPS engine by sending AT command
“AT+CGPSPWR=1”. </i><br>
</blockquote>
So it seems a GPS reset is not necessary after a software power down
/ sleep state, I'd first try without.<br>
<br>
If you find out you need to do a reset, I'd first try to cope with
"hot" / "warm". The command manual says:<br>
<blockquote><i>COLD start mode is recommended For first time reset.</i><br>
</blockquote>
So I think this is normally only needed for the first power up.<br>
<br>
Regards,<br>
Michael<br>
<br>
<br>
<br>
<div>Am 04.11.2014 um 17:42 schrieb Arthur
Hebert:<br>
</div>
<blockquote type="cite"><div><div class="h5">
<div dir="ltr">Hi All,
<div><br>
</div>
<div>Does anyone know the details of how, most reliably and most
quickly, to get a location fix from the GPS module after it
has been powered up and after it has come out of sleep mode?</div>
<div><br>
</div>
<div>I have written my own code using the OVMS hardware. To save
power, it turns off the GPS power (AT+CGPSPWR=0) and puts the
module to sleep (AT+CSCLK=2) while the vehicle is parked (i.e.
no CAN bus activity). Once there is CAN activity again, it
comes out of sleep mode (AT+CSCLK=0) and turns on the GPS
(AT+CGSPPWR=1). Immediately after turning on the GPS power, I
also issue one of the GPS reset commands (AT+CGPSRS=0 or
AT+CGPSRST=1).</div>
<div><br>
</div>
<div>The module documentation if vague about when to use the 0
reset or the 1 reset.</div>
<div><br>
</div>
<div>I know that the GPS module itself isn't made to function
while the module is asleep even though the commands may not
give an error. </div>
<div><br>
</div>
<div>I've read that it takes up to 15 minutes to get a fix on
most GPS devices. In practice, sometimes I get a fix within a
minute every time I start up, and other times I don't get a
fix even after hours of trying with either reset option. </div>
<div><br>
</div>
<div>Any information will be greatly appreciated.</div>
<div><br>
</div>
<div>Thanks,</div>
<div>Arthur</div>
</div>
<br>
<fieldset></fieldset>
<br>
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</span></blockquote><span class="HOEnZb"><font color="#888888">
<br>
<pre cols="72">--
Michael Balzer * Paradestr. 8 * D-42107 Wuppertal
Fon 0202 / 272 2201 * Handy 0176 / 206 989 26
</pre>
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