GPS tracker based on HL8548G

Hi, All!

Does anyone use HL8548G in GPS trackers?
Do you have a problem with a quality of tracks?
What type of antenna are you using?
I use an active antenna. In most cases, there are no problems with the tracks, but there is a constant displacement in the coordinates around 100-200 meters during the movement and is eliminated only after a long time. Or the situation changes significantly when there is no movement, even in open terrain (clear sky). At this time, the outcropping changes significantly (from 100m to 1500m), the remaining parameters are normal (HDOP <= 3, SV >= 7, average SNR >= 20). Perhaps you had problems with this module when building a tracker, please describe here. Soon I will attach a picture of the track and a full AT-log.

Thank you!