raider2b - 5/28/2018 08:54

All "radar" inputs are in pulses/mph. The default for a Dickey John radar is 58.94 hertz/MPH for ag use. There are different outputs but most are 59. It is just a 1.5 millisecond pulse of voltage if I remember correct.

GPS speed is actually velocity measured in knots or KM/H. For example VTG is true degrees, magnetic degrees, speed in knots and speed in KM/H. Other methods use simple lat/long comparisons and a bit of Trig to calculate speed. Most cheap GPS receivers are only capable of outputting GPS messages at 1/second, some of the cheapest are only capable of one message every 5 seconds. The sensor one speed is output at 5/second.

For a planters/drills we have found that the most reliable, fastest updating and accurate speed comes from the wheel speed sensor.