Thingy:91 problems with GPS and powering off

[jkase]

I'm running 6 X Thingy:91s in pre-production for use as a GPS tracking/iOT solution.  Currently I'm located in Austin, TX.  If I do not request GPS, I receive regular data from the units reporting to the nRF Cloud. 

Turning on GPS by holding the button, produces mixed results.  At no point have I seen GPS data inside, or under the porch roof outside -- this is to be expected, although not ideal.

I put four devices in my car while we went out for dinner.  Afterwards, one generated several GPS data messages -- the other three had powered off, never sending GPS data.

•  Are GPS antennae recommended, and if so, which are recommended?

•  The asset_tracker software is the latest version from the download location (from late December 2019).

•  I'm waiting for the SWT cable, which should arrive tomorrow, so I can update the modem firmware.

•  Any other suggestions?

•  Also, I have not found the documentation on the format for the GPS and other data.  It would be nice to know what RSRP refers to, and what the four numbers in the LIGHT data represent.  The GPS data looks something like: "GPS":"$GPGGA,234021.08,3015.19952,N,09746.77201,W,1,04,1.55,139.62,M,0,,*3B\r\n", which I'd like to convert to latitude/longitude.

Thanks,

--jeff

[Martin Lesund]

Hi Jeff, 
Unfortunately, there is an errata "Marginal GPS performance using on-board antenna".

I would recommend connecting an external antenna for the GPS that uses an adapter (Murata part no. MXHS83QE3000) so you can connect to the Thingy:91.
Updating of the Modem Firmware version will improve the performance of the device.

• RSRP = Reference Signal Received Power

I'm not quite sure what you refer to when you say LIGHT data.
Do you mean the Light sensor?

or the color of the Light from the Thingy:91?

• Purple breathing: GPS is active and searching
• Green breathing: GPS has fix

 

You can find the information about what the numbers in the GPGGA represent here.

Best regards,

Martin L.

[jkase]

Martin,

I'll order the external antennae.  You mentioned an adapter, what is that part number, or does the Murata part connect directly to the Thingy?

The LIGHT data is the data sent from the Thingy to the nRF Cloud in a JSON tag, named "LIGHT".  The data is 4 digits separated by a space.

Thanks,

--jeff

[jkase]

Martin,

I've found the antenna connector (J2) on the Thingy:91 board, which the Murata adapter connects to.  It would seem that the adapter would require punching a hole through the case.  And then, any jostling may damage the connection to the board.  Are there suggestions on how best to fit this in a production environment?

Is there a recommended antenna (part #)?  The errata mentions "... an external active GPS antenna with needed power supply".  Does the antenna require its own power supply?

I'm also concerned about the units powering off (or just losing connectivity).  I left the six devices running last night -- all blinking blue to indicate cell, but no GPS.  This morning 3 out of 6 were not blinking.  I don't know if they shut themselves off or what their state was, but turning the power switch off then on brought them back.  Thoughts?

Thanks,

--jeff

[jkase]

Martin,

I've received the Murata adapters and GPS antennae.  The adapter is attached to the J2 connector on the Thingy board.

Unfortunately, it doesn't seem to make any difference in the ability to determine location.

I have yet to see a blinking green light on any of the six units I have running.  The units are set in GPS acquisition mode, with a blinking purple light, but they never turn green.  After a while, they turn back to blinking blue.

The testing is done with the antenna attached and mounted outside, with a clear view of the sky, in Austin, TX.

Are there any other configuration items that I can perform?  Any help would be greatly appreciated.  But, at this point, the product is not providing the primary function that we purchased them for.

Thanks,

--jeff

[Martin Lesund]

Hi Jeff,

I am sorry for the delay.

I highly recommend that you update the modem firmware on the devices since the new firmware has improvements on the GPS functionality.
I would also advise you to run the latest Asset_tracker application (included as a precompiled .hex)

Have you confirmed that the devices can connect to nRF Cloud? (which network are you connected to)

Best regards,
Martin L.