Important GPS Terms: AVL, NMEA, SBAS

AVL: Automated Vehicle Location
AVL is a popular GPS function presently being built into many vehicles and popularized by services such as OnStar. AVL systems monitor vehicles in real-time and convey navigational or operational data to the driver or monitoring service. For more information on NovAtel's AVL options, visit

C/A Code: Coarse Acquisition Code
A C/A Code is a pseudorandom string of bits that is used primarily by commercial GPS receivers to determine the range to the transmitting GPS satellite. The 1023 chip C/A code repeats every 1 ms giving a code chip length of 300 m which, is very easy to lock onto.

DGPS: Differential GPS
DGPS is a technique to improve GPS accuracy that uses pseudorange errors at a known location to improve the measurements made by other GPS receivers within the same general geographic area.

NMEA: National Marine Electronics Association
The NMEA is an American national regulatory body which, among other things, sets standards pertaining to the interfacing of marine electronic devices.

PPS: Precise Positioning Service
PPS is the GPS positioning, velocity, and time service which is available on a continuous, worldwide basis to users authorized by the U.S. Department of Defence (typically using P-Code).

SBAS: Satellite Based Augmentation System
SBAS systems are a type of geo-stationary satellite system that improves the accuracy, integrity, and availability of the basic GPS signals. This includes WAAS, EGNOS, and MSAS. NovAtel is the prime supplier of GPS ground reference receivers to national SBAS networks worldwide. For further details on SBAS, visit

About NovAtel

NovAtel Inc. is a leading provider of precise global positioning and augmentation technologies designed to afford its customers rapid integration and exceptional return on investment. For information on our products or services, please contact us for more information.


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GPS Systems | Data Logger | GPS Tracking Devices | Marine Navigation | GPS Terms

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