When someone presses SOS, the instinct of most safety apps is to notify as many people as possible. Guardian deliberately does the opposite — and that restraint is the reason its responder network can actually work.
The first ring is 1 km — on purpose
Guardian opens dispatch with a precise 1-kilometre ring around the victim's live location. Only people physically inside that ring are alerted. A person 800 metres away can realistically reach someone in distress within minutes; a person 9 km away usually cannot. Alerting the second person first would add noise without adding help.
×1.6 per minute, until three responders accept
If nobody accepts within a minute, the ring grows by roughly 1.6× — from 1 km to 1.6, then 2.6, 4.1, 6.6, and finally 10 km. The expansion stops the moment three responders accept. Three is enough for real coverage without turning an emergency into a crowd.
Ring-band exclusion: nobody is alerted twice
Each expansion pings only the new outer band — the annulus between the previous ring and the new one. Everyone inside the earlier rings has already been alerted, so they are excluded. Combined with per-alert deduplication on the client, this guarantees a responder receives exactly one notification per emergency, no matter how many times the coverage recalculates.
The re-ring that follows a victim on foot
Victims do not stand still. If the person flees on foot, Guardian re-centres the coverage around their new position — and again alerts only the newly covered people. Alert fatigue is the death of every community-response system; Guardian's dispatch is engineered so that it simply cannot spam.
The result: precision first, escalation only when needed, and a responder network that stays trusted because every alert it delivers is relevant.