Ambiguity: Unknown number of complete wavelengths counted from the reference satellite to the antenna’s phase center.

 

Almanac.  Set of data containing information on the satellites’ orbits, clock corrections, atmospheric delays and other similar parameters.

 

Co-Op Tracking. Technique used in TOPCON receivers to improve the tracking performance of an individual channel by jointly using all the tracking data of all the channels.

 

CMR. Real-time data transmission protocol (Compact Measurement Record).

 

Datum. Concept that describes the ellipsoid’s position, orientation and scale in relation to the Earth.

 

DGPS. Differential GPS of code.

 

Ephemeris. Satellite orbit predictions that are transmitted as part of the data sent.

EGNOS. European service to improve the precision obtained in navigation, based on geostationary satellites (European Geostationary Navigation Overlay Service).

 

Ellipsoid. A three-dimensional object generated by rotating an ellipse around the Earth’s polar alignment.

 

Epoch. Moment in which a measurement is performed by the receiver.

 

Geoid. Surface having a constant gravitational force.

 

Elevation Mask. Angle below which the satellites will not be used to calculate the position supplied by the receiver.

 

Multipath. Interference caused by reflected satellite signals that arrive at the receiver, normally as a result of nearby structures or other reflecting surfaces.

 

NMEA. GPS receivers’ standard data transmission protocol for communications with a computer (National Marine Electronics Associations).

 

PDOP. Non-dimensional value that empirically requests the precision of the position supplied by the GPS receiver (Position Dilution of Precision). The greater the value, the less accurate the position.

 

RINEX. Standard GPS receiver data format for various manufacturers (Receiver Independent Exchange format).

 

RMS. Round Mean Square Error. Equivalent to the square root of the sum of the errors’ squares divided by the number of points.

 

RTCM. Standard real-time data transmission protocol (Radio Technical Commission for Maritime Services).

 

RTK. Real Time Kinematic.