In 2014, I was interested in the APRS (Automatic Packet Reporting System) as an amateur radio operator (ham) and therefore I got involved in the GPS reception and evaluation with a small project. A Navilock NL-625ETTL was available as a GPS reception module. This provides NMEA 0183 V2.3 frames (GGA, GSA, GSV, RMC, VTG) with 38400 bd. The self programmed controller then processes Status, Date, Quality, Latitude, Longitude, Altitude, Speed over ground and Number of Satellites.
The controller is an ATmega644 with 14.7456 MHz. The display is via a graphical LCD (128 x 68 px) and the menu control via five buttons. Six display windows (Status, WGS, Locator, Speed, DateTime, Tracking) are available. The extended locator (Maidenhead) is calculated from the WGS coordinates.
At the beginning of 2015 I implemented a data logger too. AVR-DOS was used as a file system and the navigation data are stored on an SD card. The 12 volt supply allows operation in the car.
I think a nice little project to learn about GPS, NMEA and programming (USART, File System).
 Modul pins |
 Controller |
 Controller PCB |
 Contr keypad |
 SD Card pins |
 SD Card - uC |
 GPS modul |
 All moduls |
 Frontside |
 Status display |
 WGS display |
 Inside |
 GPS control |
