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If the NMEA packet type is selected, the NMEA tab will appear in the properties window
(see Figure 36). In this tab the NMEA messages to output on the serial port are selected by
choosing the data rate for each message type from the drop-down lists and clicking the check
box for when to generate the message.
NMEA messages can also be generated in response to event input triggers. Check the falling
or rising edge check box to compute the message when the event occurs. The RT1003 can
also generate NMEA messages from pulses on the output trigger. These messages use
interpolation to compute the values at the exact time of the event but may be output on the
serial port up to 30 ms late and out of order compared to the normal messages. To enable
these messages check the appropriate check box.
Note that it is easy to overload the serial port if there are too many events. The software
computes the number of characters that will be output each second and displays this at the
bottom of the window. A serial port data overflow warning message will appear if the data
Table 18.
Serial output options
Option
Description
Disabled
The serial output is disabled. This option can be used to reduce the computational
load and ensure that the Kalman filter runs quicker
NCOM
Normal output of the RT1003. NCOM data is transmitted at up to 125 Hz over
serial. The format is described in the NCOM Description Manual. Software
drivers exist for decoding the NCOM data
IPAQ
NCOM output at a reduced rate. The baud rate of the serial port is set to 19200
and the update rate is 25 Hz. It is used because the IPAQ cannot manage to
receive the data reliably above 25 Hz
IPAQ+
NCOM output at a reduced rate and polled. Windows Mobile 5 on IPAQs crashes
if the inMOTIONx is sending data when the IPAQ is turned on. Using IPAQ+ the
IPAQ will poll the RT1003; the RT1003 will not send data while the IPAQ is off,
preventing the turn-on crash of the IPAQ
NMEA
The NMEA outputs conform to the National Marine Electronics Association
Standard (NMEA 0183 version 3.01). The NMEA sentences available are
GPGGA, GPHDT, GPVTG, GPZDA, GPGST, PASHR, GPRMC, GPGSV,
GPGSA, PTCF, GPPPS, PRDID, GPROT, GPGGK, and GPUTC. The NMEA
0183 description manual gives details of the fields output in the NMEA sentences
Javad I+RTK
A special set of messages output in GREIS format to be used with Javad
receivers. For assistance please contact OxTS for support
MCOM
Used for marine applications. Identical to NCOM output but with the addition of
heave measurements
TSS1
TSS1 format outputting acceleration, heave, roll and pitch
TSSHHRP
TSSHHRP format.
EM3000
Suitable for use with Simrad EM3000 multibeam sounders
EM1000
Suitable for use with Simrad EM1000 multibeam sounders
