Review on DY-880TTL GPS Module W/ Active Antenna, QMC5883L For APM2.6 Pixhawk Betaflight Flight Control - Glonass Beidou Support by Nick Singh

I discovered that both of the USB GPS I purchased had bad internal batteries. These are small 3 volt batteries that are used to store ephemeris data while the USB dongle is not powered. With no data backup (sometimes called Battery Backed Ram, or BBR), the device defaults to 'cold start' mode every time. I worked around this by soldering my own 3V CR2032 in a battery holder with leads to the internal circuit board. You will then need to reconfigure the device to use AssistNow Autonomous mode using the Ublox configuration tool. None of this is for the faint of heart, but I can now get GPS lock in seconds from power off. This affected all two devices I purchased.