35 
 
LED definitions 
The front panel of the RTs has some LEDs that give an indication of the internal state of 
the system and are designed to provide enough feedback so that a laptop does not need 
to be connected. They can be used for some simple operational checks on the system. 
Table 13 and Table 14 give a description of each LED on the RTs. Table 15 to Table 19 
list the precise meanings of the states of each LED. 
Table 13. RT2000 LED descriptions 
Name  Description 
SDNav  Strapdown navigator state 
Pos/Head  Position solution (single antenna) or heading solution (dual antenna) from GNSS 
Pwr  Power and communication 
 
Table 14. RT3000/RT4000 LED descriptions 
Name  Description 
SDNav  Strapdown navigator state 
Position  Position solution (only on single antenna systems) 
Heading  GNSS heading solution (only on dual antenna systems) 
GPS  Self-test 
Power  Power and communication 
 
Table 15. SDNav LED states 
Colour  Description 
Off  The operating system has not yet booted and the program is not yet 
running. This occurs at start-up. 
Red-green flash  The RT is asleep. Contact OxTS support for further information. 
Red flash  The operating system has booted and the program is running. The GNSS 
receiver has not yet output a valid time, position, or velocity.