Re: [Paparazzi-devel] lisa has a different GPS interface?

[Chris Wozny]

Does the uBlox MAX-6Q from CSG Shop have a 3.3V regulator? I didn't
think it did, so I swapped the jumpers to supply 3.3V to UART3 which
may be why mine works fine on Lisa/M 2.0 if you're having problems
with the 5V regulator on Lisa/M 2.0. I've never had problems with
"dirty" power being supplied to my GPS (whether it be LEA-5H or MAX-6Q
on both Lisa/M 1.0 or 2.0) so I wonder if it's a manufacturing defect
on your individual on-board regulator.

Also, Marvin, I know that the ubx_center module is to be used if your
GPS module doesn't save it's configuration, but maybe it would benefit
if you used the ubx_center module just to make absolutely sure all of
your settings are correct on your GPS module:

http://paparazzi.enac.fr/wiki/Module/GPS_UBlox_UCenter

Best,
Chris

On Mon, Jun 25, 2012 at 10:59 AM, Tilman Baumann <address@hidden> wrote:
> On 25/06/12 15:52, Marvin Wang wrote:
>>
>> hi Chris,
>>
>> i had tried that use ublox center in windows and it get lock within 1
>> minute,(first time), but when it goes on my lisa/m2.0, it is another
>> story. the GPS is very hard to get locked,  up to 10~20 minutes to get
>> locked on my balcony.  in the field it takes more than 2 minutes. i
>> dont know what causes this.
>
> How is it if you power the Lisa board from USB?
>
> I might have observed the same pattern. I have not looked much into it, but
> I had massive problems recently getting a stable fix. And the only change
> was that I used a UBEC to power the +5V line on Lisa.
> I might need to clean that up a bit. I don't expect that UBEC to be any good
> (no name 3A 5V thing) but since everything it ought to power actually runs
> on 3.3V I thought it might not matter so much.
> I thought the LDO will smooth that out. But perhaps they don't...
>
> Can't prove those issues yet. Just want to mention since our experience
> seems similar.
> Any tips what I should try to clean the power rail?
>
> +5V is looped through a ferrite ring a few times.
> Modem runs directl on 3.3V rail of Lisa. (could also hook it up on 5V. I
> soldered VCC behind the voltage regulator on the XBee breakout because this
> serial port was only 3.3V by default. But it's switchable)
> uBlox MAX-6Q runs on 5V with it's own voltage regulator for 3.3V