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

[Marvin Wang]

hi
i had tried the USB power, but the same result.

2012/6/25 Tilman Baumann <address@hidden>:
> 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
>
>
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