nRF9160 GPS ANT Design

[distancetu]

Please help me point out whether the antenna design is reasonable,I can't get a GPS signal this way

[ketiljo]

Have the GPS antenna been measured and tuned?

[distancetu]

There was no problem with the tests we ran,and We can use other GPS positioning modules to use this antenna can be fixed in place, not with the 9160.

[ketiljo]

What's the part number of the antenna? The tuning components do not have any values. 

Can you share the layout?

[distancetu]

ANT_GPS1 is the number of the antenna.

We can obtain satisfactory performance without adjusting the matching value when we debug the antenna.

We have not welded any of the NC devices marked in the fourth picture

[ketiljo]

Are you sure the LNA is enabled? Pin 5 must be high to enable the LNA. What does the debug log tell you?

[distancetu]

We connect the enable pin to the power supply to ensure that the enable end remains in a high level state.

The appendix file is the 9160 output log

taoci.logbanzai.log

[ketiljo]

It looks like you have a FW issue. Have you updated the modem FW? If not, please flash the latest FW and see if you get better results. 

[distancetu]

The version we use is mfw_nrf9160_1.3.6.zip

[Håkon Alseth]

Hi,

 

Thank you for sharing this info.

If we look at the GPGSV when tracking 8, banzai.log line 428-429:

00> [00:04:36.697,326] <inf> gnss_sample: [775] $GPGSV,2,1,8,1,,,24,4,,,24,6,,,23,9,,,24,1*52
00> [00:04:36.706,420] <inf> gnss_sample: [775] $GPGSV,2,2,8,14,,,06,17,,,04,18,,,29,30,,,24,1*5A

This shows a dB/Hz of the following:

PRN#1 = 24

PRN#4 = 24

PRN#6 = 24

PRN#9 = 24

PRN#14 = 6

PRN#17 = 4

PRN#18 = 29

PRN#30 = 24

 

You usually want >30 dBm/Hz to be able to successfully track a satellite, and you need 4 satellites to get a fix.

 

Do you have a nRF9160-DK to test with?

If you place the DK in the same test bench, do you see similar behavior?

 

Kind regards,

Håkon

[distancetu]

We use DK test, in the same position, you can get the positioning coordinates, it took one to two minutes.

We also tried to connect DK 9160 GPS PIN with our designed antenna to  get the positioning coordinates.but it took three to four minutes.