GPS interferes with receiving inbound Notes

1

I am currently using hub.set with mode:continuous and sync:true, and card.location.mode with mode:periodic. When the device is indoors and constantly struggling to get a GPS lock, it prevents any inbound Notes from being received. Is there a way to fix this so that the device can still receive inbound Notes quickly when indoors?

2

Hi @yunzheng,

By default the GPS on the Notecard has a 900 second timeout before it gives up on trying to locate a satellite. So if you move indoors, you will have to wait those 900 seconds. You can, however, override this value to a lower number by using the _gps_expiry_secs reserved environment variable.

As an alternative to using GPS indoors, you could also try using the Wi-Fi triangulation feature.

Thanks,
Rob

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3

What would the behavior of the GPS be after the Notecard does not get a GPS lock by the timeout? When would the next attempt to get a GPS lock occur?

In general, how long does it take for the Notecard to get a GPS lock?

4

Hi @yunzheng,

Normally the GPS will re-attempt a sync at the regularly scheduled periodic interval. However, in some cases it can be put in a GPS penalty box in order to save battery life.

It’s hard to say “in general” as it can take seconds to minutes depending on the physical environment and potential obstructions for the Notecard to see any satellites.

Rob

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5

I just tested by setting _gps_expiry_secs to 60, but still, no inbound Notes are being received. Why is this the case? I would’ve expected them to be received within those 60 seconds

6
  1. Make sure you perform a sync with Notehub and verify the environment variable has been downloaded to the Notecard.
  2. Once the GPS expiration period expires, it can take some time (again 1-2 minutes maybe depending on your cellular connection) to reestablish a cell signal. Notes should start being received then.

You might be better served by using an external GPS module and avoid these issues entirely too FYI.

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7

yenzheng,

You can also use a GPS extender, See https://www.amazon.co.jp/-/en/Amplifier-Enhanced-Transmitter-Navigator-Practical/dp/B08CK8XSTC

Regards
Rob Oudendijk