GLOSSARY 
xlv 
Sea state  Status of the sea condition due to the weather environment, expressed as a sea state 0 for flat 
conditions with minimal wind, to sea state 8 for very rough sea conditions. 
 
SET  The current direction for manual correction or the current speed on the horizontal axis of the 2-axis 
log is displayed. 
 
Sleeping AIS target  A target indicating the presence and orientation of a vessel equipped with AIS in a certain 
location. 
 
sm Statute mile1sm=1609.344m 
 
SOG  Speed Over the Ground 
The speed of the ship relative to the earth, measured on board of the ship. 
 
SP Short Pulse 
 
STAB Stabilization 
 
STC  Sensitivity Time Control 
Function of STC reduces the impact of returns from sea state of relatively near from own ship. 
 
STW Speed Through Water 
The speed of the ship relative to the water surface. 
 
T
 
TCPA  Time to Closest Point of Approach to own ship 
 
Test target  Radar target of known characteristics used for test requirement. 
 
TM True Motion 
A display across which own ship moves with its own true motion. 
 
Trails  Display Radar Trails (Other Ships' Trails). 
 
True course  The direction of motion relative to ground or to sea, of a target expressed as an angular 
displacement from north. 
 
True speed  The speed of a target relative to ground, or to sea. 
 
True vector  A vector representing the predicted true motion of a target, showing course and speed with 
reference to the ground or sea. 
 
TT Target Tracking 
A computer process of observing the sequential changes in the position of a radar target in order 
to establish its motion. Such a target is a Tracked Target. 
 
TTG Time To Go 
Time to next waypoint. 
 
TXRX Transceiver Unit 
 
U
 
USB  Universal Serial Bus
 
USB was designed to standardize the connection of computer peripherals. 
 
UTC  Universal Time Coordinated
 
The international standard of time, kept by atomic clocks around the world.
 
 
 
V
 
VRM Variable Range Marker
 
An adjustable range ring used to measure the distance to a 
target
. 
W
 
Waypoint  A geographical location on a route indicating an event.