bizzarro , my problems with gps seem to have ended after connecting to a regular car gps-antenna. Also, the Chinese said that the Internet should be available for correct operation.
What happened - after on were several satellites, some of them were locked (gps fix), after a few minutes they were lost and then or the situation repeated in a circle or lost forever. And the accuracy of determining the float in a hundred meters, if not more.
What has become - when turned on, it takes the saved position, switches to agps (accuracy of 30 meters), then (in a few minutes - I understand, until the almanac receives) finds a bunch of satellites and crashes into almost everything and works (for now) without problems
From possible problems - for example, even though I put the antenna directly under the glass, but twisting the cable of a Chinese antenna into a ring, it could affect the quality.
It is also obvious that something is amiss with the preservation of the almanac in the firmware.
Try to make a cable to the antenna 70 centimeters - can this be the case?