Novatel GPS and Freewave Radio Configuration
From MobileRobots Research and Academic Customer Support
Setting up a Novatel ProPak GPS with a Freewave radio connection to a base station.
Contents |
Configuring the Freewave Radio
Use a terminal program, such as Hyperterm in Windows, or minicom in linux. Set the port to 19200 bps, 8data bits, no parity, 1 stop bit, no handshaking.
The slave unit has a small push button on the back which allows you to get into setup mode. The master unit has a toggle switch for setup mode.
For the slave:
At the main menu -
- Push 0 for "Set Operation Mode"
- Choose 3 for Point to MultiPoint Slave
- Push ESC to get to the main menu
- Press 1 for "Set Baud Rate"
- Press 6 for 9600
- Press ESC to get to the main menu
- Press 2 for "Edit Call Book"
- Press 0 to edit the first listing
- Enter the master's serial number and then press enter
- Press ESC to not use a repeater
- Press ESC to return to the main menu
- Press ESC to exit the setup mode
For the master:
At the main menu -
- Push 0 for "Set Operation Mode"
- Choose 2 for Point to MultiPoint Master
- Push ESC to get to the main menu
- Press 1 for "Set Baud Rate"
- Press 6 for 9600
- Press ESC to get to the main menu
- Press 2 for "Edit Call Book"
- Press 0 to edit the first listing
- Enter the slave's serial number and then press enter
- Press ESC to not use a repeater
- Press ESC to return to the main menu
- Press ESC to exit the setup mode
Interference Note
Some of the telemetry links use 900MHz modems, and some use 2.4GHz. If you find that you are having interference problems with the onboard 2.4GHz 802.11b wireless ethernet, you can change the band that the modems use. The frequency needs to be changed on both units in order for the system to work. Follow the directions below:
At the main menu -
- Press 3 for "Edit Radio Transmission Characteristics"
- Press 0 for FreqKey
- Type "F"
- Press 0 for "Hop Table Version"
- Type 2 to set to lower 1/3rd of the band (the band is 2.400-2.4835GHz)
(refer to p.32 of the FreeWave manual for other options)
- Press ESC twice to return to the main menu
You can then change your wireless-ethernet client-adapter and access-point to use a higher frequency to avoid conflict.
Setup the Novatel GPS and Base Station
To configure the devices, either connect with the Novatel software, or with a terminal program. The default baud rate is 9600, 8, none, 1, no handshaking or flow control. You will need a null-modem adapter to talk to the device if you're using the robot's onboard computer. If you use the Novatel software then you can use the console window to type in the commands below. Otherwise just type the commands into the terminal window.
Base station
To see how the port is currently setup you can use:
log comconfig
Make sure that com2 is set to 9600. If not use:
com com2 9600 n 8 1 n
To setup to send L1-differential correctional data to the slave units:
(note that not all models are capable of the same types of correction)
log com2 rtcaobs ontime 2 log com2 rtcaref ontime 10 log com2 rtca1 ontime 5 interfacemode com2 none rtca saveconfig
To ensure that the log commands are actually entered correctly, use this command to print out the entries:
log loglist
The base station needs to be set to a fixed position. The position can either be found with surveying equipment, or can be estimated by the device. To enter a fixed position use the format:
fix position LAT LON ALT saveconfig
Where LAT, LON and ALT are latitude, longitude and altitude values.
To undo a fixed position do:
fix none saveconfig
To have the unit automatically set a position when powered use posave, like:
posave 0.01 saveconfig
That sets it to the position it thinks it is at after 0.01 hours of operation. You can also use std limits for lat and long, like:
posave 0.2 2 2
That waits for the standard deviations to be at least 2m or less.
To disable posave use:
posave off saveconfig
Slave unit
To see how the port is currently setup you can use:
log comconfig
Make sure that com2 is set to 9600. If not use:
com com2 9600 n 8 1 n
To make the slave unit use the correctional data, use:
interfacemode com2 rtca none saveconfig
Stand-alone unit with WAAS correction
To enable a system with Wide-Area Augmentation Services, use the following commands:
sbascontrol enable saveconfig
That will automatically look for a WAAS satellite. In the U.S., from the midwest to the east coast, use:
sbascontrol enable 122 saveconfig
From the midwest to the west coast, use:
sbascontrol enable 134 saveconfig
To turn off WAAS corrections, use:
sbascontrol disable saveconfig
Communicating with the GPS
ARIA 2.5 and later has classes for communicating with Novatel, Trimble AgGPS, and other GPS receivers using the NMEA protocol. It includes an example program, gpsExample that demonstrates how to use them and which can be used to test the GPS receiver.
This section describes connecting with minicom or other software.
If your GPS system is running on a robot with Linux installed, and if the robot came with the GPS system preinstalled, then you can type:
minicom gps
That will start up minicm and load the proper settings. That will not allow you to see what you type, however. In order to see what you are typing, you need to turn on Local Echo, by pressing CTRL-A, Z, then E.
If there is no "minicom gps" option, then you can startup "minicom -s", and setup the port to use /dev/ttyS1, 9600, 8, N, 1, and no hardware control. Also edit the modem strings and clear the 'Init string' string, and the 'Reset string' string. Save the setup as 'gps".
If you want the device to continually transmit the position information, you can use a command like:
log bestpos ontime 1 saveconfig
That will cause the device to send the bestposition information every 1 seconds. You can change the 1 to be any other number of seconds.
You can use similar commands to send data back in standard NMEA format rather than the Novatel protocol.
The full reference manual for commands refer to the OEMV Firmware Reference Manual (ProPak V3) or OEM4 Command And Log Reference (ProPak V2) from Novatel (http://www.novatel.com).
