SM200C GPS issue

Roman,

The API is setup to only return UBX messages when GPS is locked and outputting NMEA sentences. This is a result of how we package and return this data. For this reason, yes, you would need to see GPS lock before expecting messages.

Is there an event that consistently leads to lost GPS lock? Is it after sending a message? Does your GPS antenna have access to clear sky? I can’t say that I have seen a scenario or heard from a customer that a reboot of the device was required to attain GPS lock. Is it possible one of the messages is configuring the device in an undesirable state?

We only have experience sending the NAV5 message for changing the platform model. That code example is in our SDK (you probably already found it). I have not used the cold boot command. If it forces the GPS to do a cold boot, this will take many minutes or longer to get GPS lock again, I’m assuming you are waiting an appropriate amount of time?

Roman,
We have some customers who use the PPS from an external GPS as the trigger input. This marks the sample in an I/Q stream at the top of the second. The time stamping requires a little more work on your part, as you would need to interface the GPS yourself and generate the time stamp based on trigger position.