Bg77 hot start functionality


We are using a bg77 module. It finds the position approx. 3-4 minutes after cold start. But when we turn off the GNSS with AT command (doesn’t matter how long ago the module acquired our position), it seems to start with a cold start next time we turn it on. The module is powered on during the process.
Our device will be mass-produced soon, and we need to reduce power consumption.
What other steps are required for hot start functionality?

Best regards,

I faced the same problem for my application. Quectel recommanded the use of standby option to reduce the time of first found position (aka first fix) with small a mount of power consumption.

Hello @Soufien,

The power supply for the BG77 is always enabled, the modem is not turned off. Only the GNSS engine is turned on and off, so that is why we don’t understand why the modem is always doing a cold start.

Best regards,

I have understood from the documentation of BG77 that the gnss engine switching off leads to the loss of data in NVRAM. Therefore, the modem change from HOT to COLD.

First of all, thank you for your fast reply.

the gnss engine switching off leads to the loss of data in NVRAM.

That’s interesting, in this post, @ frankfeng2020 said that he can turn on and off the GNSS engine without entering cold start again.

By using the standby option do you mean the PSM (Power Saving Mode) or sleep mode?Or something else?

Best regards,

I am sorry because I am confused between L76 and BG77. I am currently using the Standby function of L76

Hi there,
Check the xtra functions in the documents, it suppose to get a fix faster if it has the correct xtra file on the module.
Also, if you have any errors from at commands maybe it’s a timeout.

Kind regards,

Thank you, we will try your advice.