SpaceLabs MicroTrackers

On 6 October and 24 November 2019 I briefly described a future project using a GNSS receiver module with a microcontroller and a display, to parse GPS NMEA text strings and display my choice of data in an easy-to-read form.
I have now completed 3 versions using different firmware, GNSS receivers, microcontroller development boards, and displays. I call them "SpaceLabs MicroTrackers".

Depending on the version, date, time, latitude, longitude, altitude, nr. satellites acquired, fix quality, and update age are displayed. Features they all have in common are a 25x25mm active ceramic patch antenna, USB interface for programming/power and Ublox Neo-6M compatible GNSS receiver module.

While waiting for enough satellites to be acquired for a position fix, version details, local temperature and battery voltage are displayed. I also designed some graphics using bitmap byte arrays and scrolling animation.

MicroTracker-3 with Arduino board, 128x64px Oled display

MicroTracker-2 with PIC board, 128x32px Oled display

MicroTracker-4 with Arduino board, 84x48px Nokia 5110 display

On MicroTracker-4 I have provided a 1 pulse per second ( 1pps ) signal on an external connector. This is an extremely accurate 1Hz pulse ( 10% duty cycle ) locked to the satellites' atomic clock. When locked-on, a LED on the GNSS receiver module flashes on/off once a second.

Waveform of 1pps signal from MicroTracker-4

A second usb socket on MicroTracker-4 gives access to the GNSS receiver module for changing its settings and displaying complete NMEA sentences on a serial terminal.

 

My recent experience gained with OLED and Nokia 5110 displays has been put to practical use.