The Pixel Watch fall detection feature is designed to differentiate between a serious fall and other movements to minimize false detections. It uses motion sensors to analyze instinctive reactions and impact force. To develop accurate algorithms, the engineering team gathered data by working with labs, analyzing real-life fall videos, and simulating different fall scenarios. The AI algorithms were then tested with stunt doubles and a group of testers. The team ensured that the feature did not inundate emergency services with false alarms and worked closely with the emergency dispatch community to improve the automatic call system. Users can enable the fall detection feature on their Pixel Watch and grant location permission for emergency services. They can also help improve the feature by toggling on the “Help improve fall detection” setting.
source update: How Google Pixel Watch knows when you fall