: The protocol uses structured binary packets. While specific documentation is often restricted to authorized personnel, it generally includes: : Identifies the start of a message packet. Message ID
Disclaimer: Technical documents such as ICD-GPS-153 and SS-M/V-500 are typically obtained through the GPS Joint Program Office (JPO). If you are interested, I can also:
ICD-GPS-150 is an older, now-superseded document titled Navstar GPS Space Segment/Navigation User Interfaces . It was the standard for the legacy "Block I" satellites.
For a practical example, Safran's VersaSync and NetClock systems use their ASCII outputs to generate ICD-GPS-153C messages over GSSIP. This allows them to emulate a SAASM GPS receiver for a SINCGARS radio, providing time and 1PPS data as if they were connected to a genuine, secure GPS source. icd-gps-153 protocol
GLI-FLO is a secure GPS PNT distribution device approved by the U.S. Air Force GPS Directorate and fully ICD-GPS-153 compliant. One device can replace up to four DAGR receivers, distributing secure PNT data simultaneously to multiple weapon or communication systems.
: A distinct byte pattern indicating the start of a new message block.
The protocol is a standard serial interface used primarily by United States military GPS receivers, such as the DAGR (Defense Advanced GPS Receiver) and PLGR (Precision Lightweight GPS Receiver). Unlike the common civilian NMEA-0183 protocol, it is designed to handle encrypted and secure data, including time and frequency synchronization for tactical systems. Core Functionality : The protocol uses structured binary packets
Provides a standardized way for host platforms (vehicles, aircraft, handhelds) to communicate with SAASM (Selective Availability Anti-Spoofing Module) receivers.
Systems like Safran's NetClock use ICD-GPS-153 message structures to emulate security components. This allows engineers to build and evaluate combat network configurations without requiring active, classified SAASM decryption modules during early-stage integration. 3. Legacy Navigation Conversions
Tanaka didn’t turn. His voice was a dry whisper. “Because the fleet network is lying, Commander.” If you are interested, I can also: ICD-GPS-150
: Data routing typically occurs over standard serial lines via rugged RS-232 or differential RS-422 connections.
The ICD-GPS-153 protocol dictates how defense hardware interacts with standard military receivers, such as the Defense Advanced GPS Receiver (DAGR) and the Precision Lightweight GPS Receiver (PLGR). It functions as a software and hardware blueprint, specifying: