C-Nav IALA Hardware Reference Manual page 98

Receiver Independent Exchange (RINEX) is a set of standard definitions and formats
designed to be receiver or software manufacturer independent and to promote the free
exchange of GPS data. The RINEX file format consists of separate files, the three most
commonly used are:
Observation (.YYo) file,
Navigation (.YYn) file,
Meteorological (.YYm) files;
Where YY indicates the last two digits of the year the data was collected.
Reference station a reference station collects GPS data for a fixed, known location. Some of
the errors in the GPS positions for this location can be applied to positions recorded at the same
time by roving receivers which are relatively close to the reference station. A reference station is
used to improve the quality and accuracy of GPS data collected by roving receivers.
Right Hand Circular Polarization (RHCP) is used to discriminate satellite signals. GPS signals
are RHCP.
Root Mean Square (RMS) is a measurement of precision also applicable for horizontal stations.
Probability for RMS is 68.3%, meaning that if 100 observations are made, 68 of them will be
within the root mean square, 1 standard deviation.
Rover is any mobile GPS receiver and field computer collecting data in the field. A roving
receiver's position can be differentially corrected relative to a stationary reference GPS receiver
or by using GPS orbit and clock corrections from a SBAS such as C-Nav.
Roving Receiver see rover
Satellite Based Augmentation System (SBAS) this is a more general term, which
encompasses WAAS, C-Nav and EGNOS type corrections.
Satellite Constellation is the arrangement of a set of satellites in space.
Satellite Message is sometimes referred to as the Data (D) code. A low-frequency (50 Hz)
stream of data on both carriers (L1 and L2) of the satellite signal. The stream of data is
designed to inform the user about the health and position of the satellite. The satellite message
can be decoded by the receiver and used for positioning in real time.
Selective Availability (S/A) is the deliberate degradation of the GPS signal by encrypting the
P-code and dithering the satellite clock. When the US Department of Defense uses S/A, the
signal contains errors, which can cause positions to be inaccurate by as much as 100 meters.
Signal-to-Noise Ratio (SNR) is a measure of a satellite's signal strength.
Single Difference between receivers is the instantaneous difference in the complete carrier
beat phase measurements made at two receivers simultaneous observing the same signal.
Single-frequency is a type of receiver that only uses the L1 GPS signal. There is no
compensation for ionospheric effects. The C-Nav1010 is a single frequency receiver.
Space Segment is the portion of the GPS system with major components in space (e.g.,
satellites).
Space Vehicle (SV) a GPS satellite.
Spread Spectrum Radio (SSR) is a radio that uses wide band, noise like (pseudo-noise)
signals that are hard to detect, intercept, jam, or demodulate making any data transmitted
C-Nav Hardware Reference Guide
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