GPS operation nRF9160

[SergioT]

Hi:

I already updated the SDK to the first release version V1.0.0 and the unit works well with NB-IoT, UART and SPI. I'd like now to include real GPS data but I can't get the GPS example to work.

I believe GPS should already be working with mfwnrf9160100 version. What am I doing wrong? Do I need an external antenna instead of the board antenna?

Of course I'm trying to get GPS data with the board exposed outside in free air.

It might be important: I am using pca10090 version 0.8.3.

[MJD093]

Can you also give us some more information on why the GPS example isn't working. Can you post the serial port log from the example or the build error if that is what you are experiencing.

[SergioT]

The example compiles and operates as expected. I just added to prj.conf the necessary lines to enable RTT in SES so that I can ee the result of the printk. I added:

CONFIG_PRINTK=y
CONFIG_UART_CONSOLE=n
CONFIG_CONSOLE=y
CONFIG_RTT_CONSOLE=y
CONFIG_HAS_SEGGER_RTT=y
CONFIG_USE_SEGGER_RTT=y

Now I can see on the Debug window:

Tracking: 0 Using: 0 Unhealthy:0
Seconds since last fix 265

Scanning [-]

The number increments every second.

I would expect ot get GPS data after some time, but nothing.

[MJD093]

Ok so the pca10090 is operating as expected. The device has been up and scanning for satellites for the past 265 seconds but it can't seem to lock on to any.

As Carl stated, the DK 0.8.2 and earlier have a mis-matched antenna circuit on the GPS antenna. Now I have never seen any information on the v0.8.3 boards (didn't know there was one). That being said, the DK manual history has only been updated for v0.8.2 and v0.8.5, I could imagine that v0.8.3 is of similar design of v0.8.2.

Could you please check your antenna circuit on the DK and compare it to v0.8.5 (see the DK datasheet, under hardware) and see if they match in the components you see. One big red flag would be the existance of a Murata RF connector (J6) on your antenna circuit. If that is on your circuit, theres a good chance your DK will not be able to use GPS without an external GPS antenna.

[Carl Richard]

I have access to both 0.8.3 and 0.8.5. Will do a quick GPS test on the 0.8.3 now to check.

[MJD093]

Quicker to tell if you see J6 on the antenna line. That would be the bad antenna circuit

[SergioT]

There is a Murata connector called J6! I checked against 0.8.5 and it is really different.

Can I connect there an external antenna ? If the matching is wrong then it might help...

[SergioT]

From I see in the schematic, the connector is already after the matching, so it will not help.

[MJD093]

It will, any external connector, such as the molex 206640 (which I use on the v0.8.5 DK cause my on-board one flicked off) don't need a matching circuit as they are designed to work off-board. They just need a 50ohm line.

If your board is basically a v0.8.2 GPS board. You have two options really, get a new DK that is of the latest hardware design or buy the murata cable that can connect to that connector and then connect an external antenna that can use the screw antenna connector thing. (seeMurata part no. MXHS83QE3000)

There is a blog post about this somewhere.