Oceaneering C-NavX1 User Manual page 106

Issue of Data, Clock (IODC) indicates the issue number of the data set and thereby provides the user with a
convenient means of detecting any change in the correction parameters. The transmitted IODC will be dif ferent
f rom any value transmitted by the satellite during the preceding seven days.
Kalman Filtering is a linear system in which the mean squared error between the desired output and the actual
output is minimized when the input is a random signal generated by white noise. The Kalman f ilter looks at a
target to remove the ef f ects of the noise and get a good estimate of the location of the target at the present time
(f iltering), at a f uture time (prediction), or at a time in the past (interpolation or smoothing). The Kalman f ilter is
a recursive estimator with two phases: predict and update. The predict phase uses the estimate f rom a previous
state to produce an estimate of the current state. The update phase uses the current state measurements to
arrive at a new more accurate estimate.
L-Band is the group of radio f requencies extending f rom approximately 400 MHz to approximately 1600 MHz.
The GPS carrier f requencies L1 (1575.4 MHz) and L2 (1227.6 MHz) are in the L-Band range.
L1 carrier frequency is the primary L-Band carrier used by GPS satellites to transmit satellite data. The
f requency is 1575.42 MHz. It is modulated by C/A code, P-code, or Y-code, and a 50-bit / second navigation
message. The bandwidth of this signal is 1.023 MHz.
L2 carrier frequency is the secondary L-Band carrier used by GPS satellites to transmit satellite data. The
f requency is 1227.6 MHz. It is modulated by P-code, or Y-code, and a 50-bit/second navigation message. The
bandwidth of this signal is 10.23 MHz.
L2C carrier frequency a L-Band carrier used by GPS satellites to transmit satellite data. The f requency is
1227.6MHz. It is identical to L2 carrier f requency except that it is also modulated by C/A code, which provides a
narrower band and is easier to track.
L5 carrier frequency a L-Band carrier used by GPS satellites to transmit satellite data. The f requency is
1176.45MHz. Like L2, L5 better characterizes the ionosphere and the atmosphere.
Land Earth Station (LES) is the point on the earth's surf ace where data is up linked to a satellite.
Latitude (Lat) is the north / south component of the coordinate of a point on the surf ace on the earth; expressed
in angular measurement f rom the plane of the equator to a line f rom the center of the earth to the point of interest.
It is of ten abbreviated as Lat.
Least Squares Adjustment is a mathematical technique used on data sets that attempts to f ind the number that
provides the 'best f it' to the data. It does so by minimizing the sum of the squares of the residuals, which are the
dif f erence between the estimated 'best f it' and the data point squared. It is carried out using an iterative process.
Furthermore, it is a method of determining the curve that best describes the relationship between expected and
observed sets of data by minimizing the sums of the sq uares of deviation between observed and expected
values.
LED acronym f or Light Emitting Diode.
LEMO is a type of data or power connector.
Logging Interval is the f requency at which positions generated by the receiver are logged to data f iles .
Longitude (Lon) is the east/west component of the coordinate of a point on the surf ace of the earth; expressed
as an angular measurement f rom the plane that passes through the earth's axis of rotation and the 0° meridian
and the plane that passes through the axis of rotation and the point of interest. It is of ten abbreviated as Lon.
Mean Sea Level (MSL) is a vertical surf ace that represents sea level.
Meridian one of the lines joining the north and south poles at right angles to the equator, designated by degrees
CNAV-MAN-061
Revision B
C-NavX1 GNSS Receiver User Manual
DOC-TEM-28-NUM Rev A Uncontrolled copy when printed
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