Encl. (1) to COMDTINST 16577.2
USCG DGPS CONOP
APPENDIX B: GLOSSARY OF TERMS
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Accuracy - the degree of conformance between the estimated or measured position of a platform at
a given time and its true position.
Availability - the percentage of time service is usable by navigator.
Bits per second (bps) - unit of measure for speed of transmission of serial digital data to the user
across the radiobeecon datalink. For example, if broadcast rate is 100 bps it takes 2.1 seconds to
send the correction information for three satellites (210 bits).
Coverage - the surface area or space volume in which signals are adequate to permit the user to
determine position to a specified level of accuracy.
Integrity - the ability of a system to provide timely warning to users when it should not be used for
navigation.
Minimum Shift Keying (MSK) - MSK is a special form of frequency modulation. MSK involves
utilizing the smallest possible frequency shift of the carrier frequency to relay digital information.
A shift up in frequency from the carrier relays a digital "1" and down a "0".
conditions for a specified period of time.
2 drms - Horizontal accuracies listed in the CONOP are all 2 drms values. "2 drms" means twice
the distance of the root mean square error. In practice, any position fix obtained using the given
system has a 95% probability of having a radial error equal to or less than the 2 drms value
expressed.
B-1