#73 Cursor On Target (COT) protocol

Cursor on Target is a simple exchange standard that is used to share information about targets. Its loosely coupled design led to multiple implementations and is used to facilitate interoperability of several systems with already fielded military software. Cursor on Target was originally developed by MITRE in 2002 in support of the U.S. Air Force Electronic Systems Center. Mitre first demonstrated Cursor on Target during a combined joint task force exercise in 2003, during which a Predator unmanned aircraft was able to operate in coordination with manned aircraft.

For more detailed info read this and this document.

The COT protocol is used with ATAK to provide an exchange between sensors + coms etc.