NavCom LAND-PAK Rev.N - Manual (Page 191)

Technical Reference Manual Rev. N
Glossary - 189
navigation (.YYn) files one of the three file types that make up the RINEX file format. Where
YY indicates the last two digits of the year the data was collected. A navigation file contains
satellite position and time information.
observation (.YYo) files one of the three file types that make up the RINEX file format. Where
YY indicates the last two digits of the year the data was collected. An observation file contains
raw GPS position information.
P/N Part Number.
P-code the extremely long pseudo-random code generated by a GPS satellite. It is intended for
use only by the U.S. military, so it can be encrypted to Y-code deny unauthorized users access.
parity a method of detecting communication errors by adding an extra parity bit to a group of
bits. The parity bit can be a 0 or 1 value so that every byte will add up to an odd or even number
(depending on whether odd or even parity is chosen).
PDA Personal Digital Assistant.
PDOP see Position Dilution of Precision.
PDOP mask the highest PDOP value at which a receiver computes positions.
phase center the point in an antenna where the GPS signal from the satellites is received. The
height above ground of the phase center must be measured accurately to ensure accurate GPS
readings. The phase center height can be calculated by adding the height to an easily
measured point, such as the base of the antenna mount, to the known distance between this
point and the phase center.
Position the latitude, longitude, and altitude of a point. An estimate of error is often associated
with a position.
Position Dilution of Precision (PDOP) a measure of the magnitude of Dilution of Position
(DOP) errors in the x, y, and z coordinates.
Post-processing a method of differential data correction, which compares data logged from a
known reference point to data logged by a roving receiver over the same period of time.
Variations in the position reported by the reference station can be used to correct the positions
logged by the roving receiver. Post-processing is performed after you have collected the data
and returned to the office, rather than in real time as you log the data, so it can use complex,
calculations to achieve greater accuracy.
Precise code see P-code.
PRN (Uppercase) typically indicates a GPS satellite number sequence from 1 – 32.
prn (Lower Case) see Pseudorandom Noise.
Protected code see P-code.
Proprietary commands those messages sent to and received from GPS equipment produced
by NavCom Technology, Inc. own copyrighted binary language.
pseudo-random noise (prn) a sequence of data that appears to be randomly distributed but
can be exactly reproduced. Each GPS satellite transmits a unique PRN in its signals. GPS
receivers use PRNs to identify and lock onto satellites and to compute their pseudoranges.
Pseudorange the apparent distance from the reference station’s antenna to a satellite,
calculated by multiplying the time the signal takes to reach the antenna by the speed of light
(radio waves travel at the speed of light). The actual distance, or range, is not exactly the same
because various factors cause errors in the measurement.
PVT GPS information depicting Position, Velocity, Time in the NCT proprietary message