Here is the interesting part: The original document is notoriously difficult to find in its pure, original form. It has been superseded by newer standards (like RTCA DO-229), yet many legacy systems still require strict adherence to the "153" timing sequences.
At its core, ICD-GPS-153 is a used to transfer functional data between a GPS receiver and a host system, such as a vehicle’s navigation computer or a handheld tactical device. It establishes the rules for the RS-232 and RS-422 serial interfaces found on standard military GPS User Equipment (UE). icd-gps-153 protocol
While most commercial drones and marine electronics use NMEA (National Marine Electronics Association) text-based sentences, is a more robust, specialized alternative for military hardware. ICD-GPS-153 (GSSIP) Primary Use Commercial/Marine Military (DoD Standard) Format ASCII Text Sentences Binary/Mixed Structured Messages Security Minimal (Standard) Supports SAASM and Anti-Jam info Typical Hardware Smartphones, Boats PLGR, Tactical Transceivers Why It Matters Today Here is the interesting part: The original document