Important GPS Terms II: RTCA, RTK, SNA

RTCA: Radio Technical Commission for Aviation Services
Also known as the Radio Technical Commission on Aeronautics, the RTCA investigates technical issues relating to aviation telecommunications and maintains an active interest in GPS technologies. For more information on the RTCA, visit

RTK: Real Time Kinematics
Real-time kinematics (RTK) positioning provides much higher differential positioning accuracy by observing a given signal's carrier phases. Common RTK applications include such things as surveying, geodesy, structural monitoring (of dams, buildings, etc.), and automated machine control (e.g. trains and aircraft). For more information on RTK, please visit

SNA: System Network Architecture
SNA refers to specification(s) of design principles (including formats, procedures, etc.) for creating network configurations of given processors for given applications. One example of a SNA is implementing a GPS/AVL system as several NovAtel clients have done. SNA is really at the core of what NovAtel does.

SVID: Space Vehicle Identification
An SVID is a unique number assigned to each GPS satellite (space vehicle) for identification purposes.

TTFF: Time-to-First-Fix
The actual time required by a GPS receiver to achieve a position solution. This specification will vary with the operating state of the receiver, the length of time since the last position fix, the location of the last fix, and the specific receiver design.

WGS84: World Geodetic System 1984
An ellipsoid designed to fit the shape of the entire Earth as well as possible with a single ellipsoid. It is often used as a reference on a worldwide basis, while other ellipsoids are used locally to provide a better fit to the Earth in a local region. GPS uses the centre of the WGS-84 ellipsoid as the centre of the GPS ECEF reference frame.

About NovAtel

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