ATGM332D onboard compass GPS module

GPS module designed based on ATGM332D module: Because the study is too tight,
                                                                                    the module has not been verified yet. It is recommended to choose ATGM332D-5N-71, which supports three-mode satellite positioning: GPS, BDS, and GLONASS. You
can also choose other models of ATGM332D-5N. The module package sizes are all Same, but different number of supported satellite types. (Please refer to the module data manual for details)
The onboard HMC5883L electronic compass
with RTC clock power supply is used for data storage and hot start. No initialization is required for each startup, and star search is faster. The RTC power supply uses ML414 button rechargeable memory battery.
 
 
The PCB uses 4 Layer board design, the impedance of the ceramic antenna feeder connection line is controlled to 50ohm.
The top layer is the 5V power input and signal lines
. The first layer is the 5883L IIC signal line and other traces. The bottom of the first layer of copper foil antenna feeder has been hollowed out. ! ! ! Note: The hollowing out below the antenna feeder on the inner layer here has been modified. See PCB for details. (The IIC traces here are low-speed signal lines and do not need to be of equal length, but it does not affect the equal length), because I have a bit of obsessive-compulsive disorder. The second layer is copper for the 3.3V power supply and the bottom copper for GND as the antenna reference surface.
It is fully covered with copper, but with copper leakage. As the reflector antenna of the ceramic antenna,
 
choose a passive ceramic antenna with a thickness of 25x25x4mm.
GPS ceramic chip antenna:
The quality of the ceramic powder and the sintering process directly affect its performance. The ceramic sheets currently used on the market are mainly 2525, 1818, 1515, 1212, and 9*9. The larger the area of ​​the ceramic piece, the greater the dielectric constant, the higher its resonant frequency, and the better the reception effect. The thickness of the ceramic piece will also have a significant impact on the antenna performance. If space allows, it is recommended to choose a thickness of 4mm.
 
 
Regarding PCB ordering:
Choose 1.2mm for board thickness.
Choose impedance: JLC04121H-7628 (generally recommended/free).
 
 
This is the end of the structural introduction. For details, you still have to refer to the circuit diagram and data manual.
If there are any errors in the design or writing, I hope everyone can correct me! ! !
 
It's not easy to make, so I hope you can support me, hehe...