: To maintain maximum synchronization accuracy across battle management systems, specific data segments are strictly governed to transmit at precise intervals—ranging from rapid 1 Hz updates down to slower background routines. Core Applications in Military Hardware
: Unlike most civilian GPS interface documents, the full technical specification for ICD-GPS-153
You cannot find ICD-GPS-153 on a public website. It is (Export Controlled) or higher. You must have a U.S. government contract, a Non-Disclosure Agreement (NDA) with the DoD, and a valid export license (for non-U.S. entities). Request it via the GPS Support Center or your prime contractor.
Note: In secure timing emulation scenarios, these messages strip out localized positioning and velocity records (often zeroing them out) to transmit master timing and state synchronization without handling controlled operational data. Strategic Importance in Military PNT Infrastructure
NetClock and other advanced time servers can generate ICD-GPS-153C messages to emulate a SAASM GPS receiver. This allows modern, highly stable network time servers to feed high-precision time (1 PPS) to legacy tactical radios (SINCGARS) or specialized platforms without needing a physical SAASM receiver attached to every piece of equipment. icd-gps-153 protocol
It is also possible the number "153" was a corruption of .
Understanding the ICD-GPS-153 protocol requires dissecting its three main components: the hardware, the GSSIP structure, and the specific message types .
The ICD-GPS-153 protocol has several advantages, including:
The ICD-GPS-153 protocol, also known as the Interface Control Document for GPS-153, is a technical standard that defines the communication protocol between a GPS receiver and a host device. This protocol is widely used in various applications, including navigation systems, tracking devices, and other GPS-enabled equipment. : To maintain maximum synchronization accuracy across battle
| Field | Size (Bytes) | Description | | :--- | :--- | :--- | | | 2 | Unique start-of-message characters (e.g., 0xAA, 0x55) | | Message Type | 1 or 2 | Defines the payload content (e.g., position, time, almanac) | | Length | 2 | Length of the payload (excluding header and checksum) | | Payload | Variable | Encrypted or unencrypted data fields | | Checksum | 2 | CRC-16 or similar for error detection |
The primary "heartbeat" containing Position, Velocity, and Time.
For instance, master timing platforms use the protocol to emulate a Single Channel Ground and Airborne Radio System (SINCGARS) interface attached to a SAASM GPS receiver. Three primary messages handle this emulation: 1. Current Status (Message 5040) : 1 Hz (once per second).
The , also known as the GPS Standard Serial Interface Protocol (GSSIP) , is a critical technical specification governing how GPS receivers—specifically those with secure military capabilities—communicate with other defense systems. As an Interface Control Document (ICD), it defines the precise data structures, message formats, and timing required for interoperability between GPS hardware and tactical equipment. You must have a U
Provides raw measurement data. Status Messages: Channel, satellite, and SAASM status. Time Mark (8504): Supports precision timing data.
: Unlike standard NMEA messages, this protocol outputs high-fidelity data including Position, Velocity, and Time (PVT) , Pseudorange (PR), Delta Range (DR), and detailed SAASM/satellite status information.
This article provides a deep dive into the purpose, structure, and applications of ICD-GPS-153, focusing on its role in military PNT (Positioning, Navigation, and Timing) solutions. 1. What is ICD-GPS-153 (GSSIP)?