Hightech in the Background: From LORA-GPS and RFID-Tags to 4G
With this project, Swisscom and Apps with love have done pioneering work and implemented an exemplary use of new technologies in the middle of the Swiss mountains. Of course, the technologies used have changed over the years.
LORA-GPS technology and frozen trackers
At the PdG 2018, the participants in the Patrouille des Glaciers were tracked via the low-power network for the first time. LORA GPS trackers were used to transmit the current position of each individual team in real time. We were forced to find trackers that were also resistant to the low temperatures. To do this, we deep-froze the trackers in the laboratory with Swisscom to simulate the extreme weather conditions of the PdG and test them properly.
The trackers sent their position, temperature and battery status via the LORA network to the Swisscom LPN gateway, which forwarded this data to the backend system of the PdG app. There they were stored in an in-memory cache and immediately transmitted to the interested apps and web browsers via MQTT.
Time measurement via RFID Tags
Time measurement took place at various checkpoints along the course, using RFID tags that each athlete wore. Each time measurement was immediately transmitted to a backend of the official timekeeper via the 4G mobile network. There, data (time, results and rankings) is calculated in real time and transmitted to the PdG backend, from where the data then again is transmitted to the apps via MQTT.
Real time due to MQTT and in-memory processing
For the streaming of real-time data (locations, timings, rankings) to the apps and web browsers we used MQTT for the first time, a machine-to-machine communication protocol designed for IoT devices. In total, over 700 million messages were transmitted via MQTT during the two days of the race, with one message averaging around 340 bytes in length. In combination with the in-memory processing of all race data, we were able to display the time measured at a physical checkpoint in the app within milliseconds.
4G as State of the art in 2024
Today, 4G is in use along the entire route. This means that both the determination of positions and timekeeping are carried out via GPS trackers, which transmit data via 4G.