When will eDRX+GPS sample program be available on nRF9160?

[Yusuke]

I know PSM+GPS works on nRF9160.

Then when will eDRX+GPS sample program be available on nRF9160? Thanks.

[Didrik Rokhaug]

Hi.

For questions about future features, you should contact your Regional Sales Manager.

If you do not know who your local RSM is, you can send me a private message, and I will provide the contact details.

Best regards,

Didrik

[Yusuke]

new nrf fw and modem fw are released.

I read README.rst of asset_tracker and apparently it is possible to use eDRX and assisted-GPS(AGPS) concurrently in the fw.

However, it's not clear how to use them. The README.rst only says "Set 'y' to CONFIG_POWER_OPTIMIZATION_ENABLE. 

I would like to send AGPS data to own AWS IoT server, not nRF Cloud one. 

How can I achieve it?

Also, what happens if data is received through LTE while GPS receivers works?

Thanks

[Yusuke]

This page confuses me. These two statements conflict. 

"A GPS receiver is integrated into the radio offering various modes of operation to suit a wide selection of applications that employ location-tracking functionality"

"GPS L1 C/A receiver during LTE PSM mode"

[Didrik Rokhaug]

Yusuke said:

I read README.rst of asset_tracker and apparently it is possible to use eDRX and assisted-GPS(AGPS) concurrently in the fw.

 I am not able to find any references to either A-GPS or GPS during eDRX. Can you provide me with a link to the relevant lines? To my knowledge, while the modem supports A-GPS, NCS does not yet have any way of providing the necessary data to the modem. For a timeline on this, I must again refer you to your RSM.

To request eDRX in the asset_tracker application, set CONFIG_POWER_OPTIMIZATION_ENABLE=y and set Switch to "N.C." (note that the switch must be set after the program has started). To change the requested eDRX value, you can set CONFIG_LTE_EDRX_REQ_VALUE to the requested value.

Yusuke said:

I would like to send AGPS data to own AWS IoT server, not nRF Cloud one.

 I assume you want to send GPS/position data to your server? I am not very familiar with AWS, so I do not know how much "extra" there is in nRF Cloud, or how easy it is to port the nrf_cloud library to your own AWS instance, but you can change the hostname used by the nrf_cloud library by setting CONFIG_NRF_CLOUD_HOST_NAME in prj.conf.

Yusuke said:

Also, what happens if data is received through LTE while GPS receivers works?

 This is impossible. You cannot use GPS and LTE in parallel. During eDRX and PSM cycles, the network stores data sent to the device. The data will be sent to the device when the device is available for receiving data.

[Yusuke]

> I am not able to find any references to either A-GPS or GPS during eDRX. 

asset_tracker uses a real GPS and Request eDRX mode is supported according to README. So I think GPS and eDRX should be available at the same time. 

Also, from https://www.nordicsemi.com/Products/Low-power-cellular-IoT/nRF9160/Download#infotabs

A GPS receiver is integrated into the radio offering various modes of operation
to suit a wide selection of applications that employ location-tracking functionality

I thought "various modes" means eDRX, AGPS, and other modes.

-----------

>To my knowledge, while the modem supports A-GPS, NCS does not yet have any way of providing the necessary data to the modem.

I'm not familiar to modem firmware, but ncs seems to be a MCU side firmware. AGPS is related to modem firmware, and the source of the modem firmware is not open to the public.

[Yusuke]

Agps is supported in modem fw but not in nrf fw yet

devzone.nordicsemi.com/.../agps-released-in-v1-1-0

[Didrik Rokhaug]

Yes, asset_tracker (and other applications) now supports GPS in eDRX. Sorry for not being clear enough in my last reply.

 

Yusuke said:

I thought "various modes" means eDRX, AGPS, and other modes

 The various modes of the GPS are:

• Single shot (cold start mode by default)
• Position fix per fixed interval, configurable between 10 s - 0.5 hour: first start with cold start, sequential fixes with hot start
• Continuous tracking

[Yusuke]

Hi, Didrik.

nrf v1.3.0 is released.

I would like to use eDRX + Assisted-GPS(google supl server), but asset tracker program uses Nordic supl server. How can you implement it? Thanks

[Didrik Rokhaug]

I am not sure I understand exactly what you are asking here, what exactly is it you want?

Using GPS + eDRX is as simple as just running the GPS while connected to the LTE network, and using LTE.

The program flow might be something like this:

1. Start the application, do various initialization.

2. Connect to LTE network.

3. Connect to server, do initialization that requires LTE.

4. Request (and enter) eDRX

5. Start the GPS

6. Do regular reporting, etc.

When adding A-GPS to the mix, point 5 gets expanded:

5.1 The GPS requests A-GPS data

5.2 Start the SUPL session (at this point, it is recommended to stop the GPS, especially if using NB-IoT)

5.3 Inject SUPL data (and restart the GPS)

Does this answer your questions?

Best regards,

Didrik

[Yusuke]

Thank you. it works out!