A lot of SparkFun’s GPS product pages link to this “GPS Tutorial by Michael Simpson”, e.g.:
https://www.sparkfun.com/products/10922
It leads to a 404 error; you might want to link to the wayback machine instead:
https://web.archive.org/web/20130415071 … /GPS.shtml
Google: [site:sparkfun.com “GPS Tutorial by Michael Simpson”](site:sparkfun.com GPS Tutorial by Michael Simpson - Google Search)