I picked up a few kits from QRP Labs and have been building them over the past few days. I just finished up the relatively-quick build for the QLG1, a standalone GPS receiver and clock source.

It may or may not be common knowledge that GPS satellites have the ability to provide very accurate time signals. It’s advertised that this will typically be within 40ns of the true value.

I plugged in the receiver and connected to it from my laptop via a USB/Serial connector. Here’s what I got:

GPS serial data flying by

Here’s what a line looks like:


I looked it up and this is a data format known as NMEA. Here’s a brief overview “$” starts a message, comma (“,”) is the delimiter. After that the “GP” indicates that we’re talking to the US-based GPS system. The next three letters indicate the type of message. A “GGA” message is a location fix. The fields are, in order:

  • 212759.000 UTC time string, e.g. 21:27:59.000
  • 4304.2770 decimal latitude, e.g. 43.042770
  • N north of the equator
  • 08925.9501 decimal longitude, e.g. 89.259501
  • W west of the prime meridian
  • 2 fix quality (2 = DGPS fix)
  • 8 number of satellites used in this fix
  • 1.06 horizontal dilution of position
  • 281.5 altitude above sea level
  • M (in meters)
  • -34.2 height of geoid at this position (as it differs from WGS84)
  • M (in meters)
  • 0000 empty field
  • 0000*64 empty field, then checksum (*64)

It’ll be fun to use this with the other kit that I got (the QCX transceiver) and maybe in other projects that need a little serial GPS data.