GNSS XTRA File - Startup Infos

Hello Forum,

We use the BG600L-M3 with GNSS for a Long-Time-Tracker
The XTRA function is really very convenient!

But I wonder: As I remember for (older) A-GPS the Time AND a (rough) Location (ca. 50km?) was required.
Now, with XTRA only Time (via “AT+QGPSXTRATIME”) is OK? What happens, if the devices has moved a longer distance (e.g. 500km) between two GNSS requests but XTRA file might still be valid (Modem is sleeping/switched off between)?

(Remark: We have the chance to get a rough position, because after wake-up always the Server is contacted first (knowing the cell tower position) and synchronising the Loggers Time, then GNSS is started (only optionally to save power)).

Thanks and kind regards,
Jo (

you are right , if the gps want to hotstart , it needs to know four variables, ephemeris/almanac/ time and old position,

In fact , the Xtra file include ephemeris and almanac for next 3 days .
if the module does not move long distance ,and restart to locate in 2 hours , the GPS will do hotstart.
if the gps have move a long distance , The relocation interval is in 2~6 hours , the module will do warmstart .
if the relocation interval is greater than 6 hours , the module will do cold start.

You know , if the module has downlaod the Xtrafile in BG660L , it will try to do warmstart , instead of coldstart .

Hello Stephen,
thanks for the infos! That is very interesting to know, that <2 hours + XTRA will give hotstart.
But, do you think there will be any chance to also inject rough position, because it is easy to get via Cell-IDs? And could save a lot of power.
Best regards, Jo

(BTW: I think it might always interesting to know about end products: here it is a LowCost data logger for scientific use (Global Climate Change):
It has some internal sensors (T/rH, Baro, IMO), but mainly designed for external SDI-12 sensors (with open architecture (more infos on my github: JoEmbedded). And I am really happy about my decision to use Quectel (customer originally wanted to use another manufacturer). Congratulations for the excellent BG600L-M3!)

Sorry for the inconvenience , up to know , there is no AT or API for injecting location info。

In the scenario of <2 hours + XTRA , the module will do hotstart ,and use the last position saved in module .

Do I understand correctly, that after 6 hours there will be cold start even if correct XTRA data are uploaded? Will XTRA data help in this case to shorten TTFF?

Hello Andrey,
did you find a solution? I used the BG600-GNSS for a product, but for another product the current consumption is too high and Mobile Network is rare there. So the customer considered using an L86-GNSS-only module as preferred GNSS-Source (uses 5-20mA (FLP-Mode) instead of BG600 with ca. 60mA) . I saw in the docus, the L86 now supports Assisted GPS. Could be an interesting alternative. If you are interested, maybe we could cooperate for some technical details? I have a lot of drivers for Quectel (Modem and GNSS) and CPU is any module of NRF52 with BLE. I also have BLE drivers for JS and .NET (C#) (See JoEmbedded Github)…
Best regards, Jo