Search & Rescue

1. At the rubble

   The field team works right beside the rubble. A short-range Bluetooth link may help establish first contact with a phone that cannot be reached physically.

   First contact at close range

2. Inside the void

   The person’s phone broadcasts a help signal from a void beneath concrete slabs. Bluetooth signals can pass through some walls and floors; thickness, reinforcement and gaps affect the result.

   A phone inside. A team just outside.

3. Offline contact

   The nearby team discovers the help signal. Once compatible devices establish a direct link, they can exchange status and messages without internet or a cell tower.

   “We are the field team. We received your message.”

4. Follow the signal

   Signal strength (RSSI) and relative location estimates can help narrow the search. Comparing measurements from several positions depends on measurement quality; a single signal does not provide an exact location.

   A clue to narrow the search area

5. Authorized team

   A previously issued, signed Crisis Connect role certificate can be checked on the device. This lets the field team prove its authority offline by verifying certificate validity and the device’s signature.

   Authority that can be verified offline

Both sides need a compatible app, Bluetooth enabled, required permissions and sufficient battery. Device and platform support may differ. Location data may be missing or stale.