Novatel Software Version 4.45 OM-20000026 Rev 1 System Initialization

1 Quick Start

• An RTCAOBS message contains reference station satellite observation information, and

should be sent once every 1 or 2 seconds.

• An RTCAREF message contains reference station position information, and should be

sent once every 10 seconds.

2. RT-20 requires that the reference station periodically transmit either the RTCA messages listed above (the

recommended option), or the RTCM SC-104 Type 3 & 59N messages:

• A Type 3 message contains reference station position information, and should be sent

once every 10 seconds (although it is possible to send it as infrequently as once every 30

seconds).

• A Type 59N message contains reference station satellite observation information, and

should be sent once every 2 seconds.

Further information on RTCA and RTCM message formats is cont ained in Chapter 6.

System Initialization

The RTK system is designed for ease of use: you set up the remote station, enter a command so that it accepts RT-

2 or RT-20 messages from the reference station, and are ready to go. There are options, however, which can be

used to adapt the system to a specific application. Some options apply only to the reference station, while others

apply only to the remote station. Detailed descriptions can be found in Appendix C, Commands Summary.

In the following sections, keep the following in mind:

• Dynamics modes. For reliable performance the antenna should not move more than 1-2

cm when in static mode. See the RTKMODE commands in Chapter 2 and Appendix C for

more information.

• When using the FIX POSITION command, the height entered must be in metres above mean

sea level; it will be converted to ellipsoidal height inside the receiver. You can enter an

undulation value, if desired, using the UNDULATION command; if none is entered, the

receiver estimates an undulation with its internal table. The format of the optional station

ID field depends on whether RTCM or RTCA messages are being used: if RTCM, any

number from 0 - 1023 is valid, while if RTCA, any 4-character string of numbers and

upper-case letters, enclosed in quotation marks, is valid. See Appendix C for additional

information on the station id field.

• The COMn field refers to the serial port (either COM1 or COM2) to which data

communications equipment is connected. The serial port assignment at the reference and

remote stations need not be the same; e.g. a radio transmitter might be connected to

COM1 at the reference station, and a radio receiver to COM2 at the remote station.

The following commands will enable RTCA-format messaging and allow RT-2 or RT-20 to operate with the

remote station either at rest or in motion. Note that the optional station health field in the existing FIX POSITION

command is not currently implemented in NovAtel’s RTCA messages, though it will be in the future.

fix position lat,lon,height,

log com

,rtcaref,ontime,interval

log com

,rtcaobs,ontime,interval

Example:

fix position 51.11358042,-114.04358013,1059.4105,”RW34”