Selected Q & A: about altitude and output formats


  1. I am planing to buy UPM-Std and UPM-Lite kits to set up RTK base station and rover. I looked for accurancy is horizantally 1cm but how is the vertically accurancy ?
  2. From NMEA serial port is it 2000 or NMEA 0183, we can get GGA, VTG or RMC massages 10hz or 5HZ and what about BAUD 34,400 ? We are planing to make control module to control our hydraulic cylinders with your GPS system the accurancy of our business must be maximum 8mm or 10mm.


  1. An one hour vertical accuracy plot is as attached for your reference, the 1-sigma standard deviation is 7.35mm.

  2. It’s NMEA-0183 being output. Only GGA and RMC is updated rate related, other slow changing or overlapping redundant information is being output at 1Hz to reduce serial bandwidth required. So only GGA and RMC will change to 5Hz or 10Hz according to configured update rate. The rover NMEA-0183 output update rate can be configured, default is 115200, can change to 38400. Base input baud rate required by the rover is fixed at 115200.
    A figure showing altitude is below.