Hi @cyclin_al1
At your suggestion I re-performed several of the tests to try to better understand position vs. orientation–
My original concern was that Earthward orientation was going to have a negative impact on GPS fix and it would be compounded by positioning under the dash. My first set of tests in my earlier post were too limited in that they changed both orientation and position together, so while they did prove to me that the Carloop GPS won’t get a GPS fix while plugged into my OBD-II port, they didn’t prove whether orientation was a factor in the problem or not. So, I revisited the tests with changes to attempt to determine whether it was orientation or position that caused the GPS fix issues.
A few specific points I wanted to address after my latest set of tests–
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You were absolutely correct that position in the car was a larger factor than orientation, in fact in these new tests orientation does NOT seem to matter at all, so my original concern over that is settled in my mind: Orientation does not impact GPS fix time
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My original “on the seat” test was invalid–I realized after I posted that I had the chip antenna in physical contact with the plastic tub I used to keep it up off the seat… I now believe that physical contact w/ the antenna was the cause of not getting a GPS fix in that case, not the Earthward orientation. The GPS antenna in physical contact with an object may prevent GPS fix.
In the new tests I tested the Carloop GPS running w/ a Particle Electron 3G off a 4400mAh battery. I used 3 different positions in the car: “on dash”, “under dash”, and “on seat”. With on/under dash I used two different orientations: Earthward and Skyward, and with on seat tests they were all Earthward orientation but one with the GPS antenna in physical contact with something and one without.
For this set of tests I used a cardboard coffee cup sleeve to keep the GPS antenna from touching anything when in the “Earthward” orientation.
Position “On Dash” –
Whether oriented toward sky or earth, the GPS fix happened within 50-90 seconds.
Oriented toward Earth:
Oriented toward Sky:
Position “Under Dash” –
To simplify things I didn’t use the OBD-II connector this time, instead I placed the device on the floor of the car under the OBD-II location. No GPS fix occured within 6 minutes, regardless of the orientation.
Oriented toward Sky:
Oriented toward Earth:
Position “On Seat” –
This position was different from the others in that I didn’t test orientation, but rather whether the GPS antenna being in physical contact may have made my earlier test invalid. I didn’t have the plastic tub with me this time, but I figured the seat itself would do… What I found was that when the antenna was not touching anything a fix was obtained in about the same time as the “on dash” positions, and when the antenna was physically touching the seat no fix would be obtained within ~6 minutes. My assumption is that my earlier test in this position was invalid because the GPS antenna was resting in physical contact with the plastic tub.
Oriented toward Earth, but with GPS antenna out of physical contact with anything, GPS fix in about 90 seconds:
Oriented toward Earth, but with GPS antenna in physical contact w/ the fabric seat, no GPS fix even after ~6 mins:
If you’re still reading, thanks for your interest, and I hope that something I posted here may be valuable or at least entertaining.
…and yes I did sit in my car for about an hour doing all this, but fortunately it was still within WiFi range of my office