Sokkia GSR2700 IS, Инструкции по эксплуатации, Страница: 77 / 87

Glossary
66 GSR2700 IS Operations Manual
S
SLA— Sealed Lead Acid battery.
SIM card— Subscriber Identify Module card. A small printed circuit
board that must be inserted in any GSM-based mobile phone when
signing on as a subscriber. It contains subscriber details, security
information, and memory for a personal directory of numbers. The
SIM card also stores data that identifies the caller to the network
service provider.
T
TNC— A threaded version of the Bayonet Neill-Concelman (BNC)
connector.
Time-To-First-Fix (TTFF)— The actual time required by a GPS
receiver to achieve a single point position solution. This specification
varies with the operating state of the receiver, the length of time since
the last position fix, the location of the last fix, and the specific
receiver design.
U
Universal Serial Bus (USB)— An external peripheral interface
standard for communication that supports data transfer rates up to
480 Mbps.
Universal Time Coordinated (UTC)— The time as maintained by the
U.S. Naval Observatory. Due to variations in the Earth's rotation, the
UTC is sometimes adjusted by an integer second. The accumulation
of these adjustments compared to GPS time, which runs
continuously, caused an 13 second offset between GPS time and UTC
at the start of 1999. However, after accounting for leap seconds and
using adjustments contained in the navigation message, GPS time
can be related to UTC to within 20 nanoseconds or better.