[FOSS-GPS] FOSS-GPS Digest, Vol 80, Issue 3

[arwooldridge]

Simon,
Try using anti vibration mounts.
I too  have seen the effect of a sharp tap on the ublox earlier units.
Regards
Anthony Wooldridge

On 01/09/2015 21:03, Felipe G. Nievinski wrote:
>
>     Date: Tue, 1 Sep 2015 13:05:25 +0200
>     From: Simon Treny <simon.treny at gmail.com
>     <mailto:simon.treny at gmail.com>>
>     To: Open Source GPS-related discussion and support
>             <foss-gps at lists.osgeo.org <mailto:foss-gps at lists.osgeo.org>>
>     Subject: [FOSS-GPS] Shocks/vibrations on antenna and cycle slips
>     Message-ID: <C764E181-99B8-4B0F-9FB0-858E3684456B at gmail.com
>     <mailto:C764E181-99B8-4B0F-9FB0-858E3684456B at gmail.com>>
>     Content-Type: text/plain; charset=us-ascii
>
>     Hello all,
>
>     I'm using RTKLib to perform RTK positioning using UBlox M8T
>     evaluation-kits (EVK). I have great results when the GPS antenna
>     is attached on the rooftop of a car driving on a track (accuracy
>     <10cm).
>     But as soon as a I attach the EVK and the antenna on a quad bike
>     and drive on a bumpy road, the accuracy becomes really bad (the
>     distance between 2 antennas can be off by >3 meters).
>     In both cases, I have a clear view of the sky and no tree or
>     building around.
>
>     By looking at the recordings with RTKPlot, I've noticed that I get
>     much more losses of lock when the antenna is on the
>     quad-bike/bumpy-road rather than on the car/track. My guess is
>     that the shocks caused by driving on the bumpy-road causes these
>     losses of lock. I've measured with the accelerometer of my phone
>     the acceleration on both the car and the quad-bike: on the car,
>     the vertical acceleration never goes beyond 3g, while the vertical
>     acceleration on the quad-bike can go up to 8g.
>
>     I've reproduced this observation by attaching the antenna on a
>     pole, and shaking the pole vertically. As soon as I shake it, many
>     losses of lock occur.
>     If I do the same by attaching the EVK on the pole and letting the
>     antenna static on the ground, there is no loss of lock (excluding
>     the possibility that it comes from the oscillator).
>
>     Is this a known issue with low-cost receivers/antennas? Is there a
>     way to improve the situation? Are there other low-cost receivers
>     that support shocks or vibrations better than the UBlox M8T?
>
>     Cheers,
>     Simon
>
> The datashet says: "Operational limits: Dynamics ≤ 4 g"...
>
> <https://www.u-blox.com/sites/default/files/products/documents/NEO-LEA-M8T_DataSheet_(UBX-14006196).pdf 
> <https://www.u-blox.com/sites/default/files/products/documents/NEO-LEA-M8T_DataSheet_%28UBX-14006196%29.pdf>>
>
> -F.
>
>
>
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