NavCom Sapphire Rev.J - Manual (Page 325)

Sapphire Technical Reference Manual Rev. J
325
2.72 NMEATTM (ASCII)
SF-3050 Sapphire SF-3040
Supported Output Rate: OFF ONCE OnChange OnTime
OnChange = based on [MBRTK1B]
OnTime = highest rate licensed
This output stream is only supported on an MBRTK Rover and displays baseline information
including the baseline distance, bases speed and direction, and closest point of approach based
on NMEA 0183 Standards version 4.0.
Table 159: TTM Message Output Format
Output
Format:
$GNTTM, Base Number,Base Distance,…,UTC,Type of Acq,*hh
Field# Field Name Description
F1 Base Number Last 2 digits of the MBRTK BaseID
F2 Base Distance 3D Baseline Distance (m)
F3 Base Bearing Base 2D bearing from the Rover, N=0
o
, E=90
o
(0
o
-360
o
)
F4 Bearing Units True or Relative (T/R), R is not supported
F5 Base Speed 3D speed of the Base (m/s)
F6 Base Coruse Base 2D direction, N=0
o
, E=90
o
(0
o
-360
o
)
F7 Course Units True or Relative (T/R), R is not supported
F8
CPA Dist Distance at the closest point of approach, this is how close the Base
and Rover would ever get given their course and speed in 2D (m)
F9 CPA Time Time until 2D CPA, - means it has passed (min)
F10
Speed/Dist Units Units of measurements used:
K = Kilometers (metric, used)
N = Knots (unused)
S = Statute miles (unused)
F11 Base Name Full Base ID
F12
Base Link Status Tracking status of the Base:
L = Lost track of Base (Non RTK Mode)
Q = Query, acquiring (RTK Float)
T = Tracking (RTK Fixed)
F13 Tracking Ref R if base is used to determine own position (always true)
F14 UTC Standard UTC time (hhmmss.ss)
F15
Type of Acqusition A = Automatic (used)
M = Manual (unused)
F16 *CRC Checksum
Example: $GNTTM,30,16.75,134.27,T,0.03,34.96,T,15.99,2.63,K,530,T,R,201345.00,A*45

There will be some noise in the base velocity due to the baseline velocity of the rover. This
noise will increase if the rover is moving in a non-linear path.