Velodyne Pucm

VELODYNE PUCK - cannot figure out how to change title.

Has anyone interfaced a JAVAD GNSS (SIGMA) with the Velodyne Puck? The Puck requires a NMEA RMC message ($GPRMC) at 1 Hz trasmitted at 9600 baud over a serial cable and a 1Hz PPS TTL signal. I dumbed down the RMC message from $GNRMC to $GPRMC and am able to read the message on my computer as follows:


When I wire the Velodyne Interface box I can see the PPS signal but not the position.

I found the following in the Velodyne documentation -

Voltage Levels
The sensor accepts CMOS level inputs. Voltages 0.8 V and below are low and 1.4 V or above are high.

The RS-232 voltage level may swing from ground to supply voltage. The interface box is just a pass through to the sensor. Reverse voltage protection is built into the sensor.

Does anyone know the voltage levels on the JAVAD serial ports? Or has anyone solved this problem?

Jim Mitchell
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Best solution I found was GPS-18 terminated with the connector that plugs straight into the Velodyne box. $60 + shipping

We are now using the SBG Ellipse2-D for orientation and position and the signals provided work with the Velodyne.

It turns out that the RS-232 signal from many receivers needs to be converted to a TTL level signal. You also have to dumb down the NMEA RMC message to be GPS only. I was able to do that in my Sigma by turning off all the constellations except GPS. I purchased a RS-232 to TTL converter from StarTech ( ) but have not tried it with my Sigma.

Good Luck.