I am using ET318. The module has a very good Time To First Fix in low signal conditions.
However there is a large error in the fix. When tested over several days from a stationary location
the horizontal location varied by as much as 220m. Also for a 4 minutes during the three days test,
There was an error of 2.1 Km in the reading!
Following information would help me:
1. PCB artwork for test setup. Especially the RF sections of the PCB.
2. Rating/Type of components used on the RF line. Other than just the value of Capacitor/Inductor.
3. If weak signals are the root cause, whether the module can be configured to not give a fix when signals are weak.
4. Is there a high accuracy, low sensitivity alternative available?
I have implemented some checks in software to check PDOP, HDOP and VDOP valies. However in many cases the module reports good values for these parameters even when accuracy is poor. Due to this, sometimes readings with large errors pass through the software checks.