The popular theory is that it's a RTK differential GPS system: base station in the tripod transmitting correction information to the remote unit. The explains the warmup time, the accuracy, as well as the big price tag.
Ha! I found your question a couple months ago after youtube hit me with the soloshot ad, and I couldn't figure out how it worked. Despite being downvoted, it still ranks fairly high on the SERP for "how the hell does the soloshot work, their site is useless".
http://electronics.stackexchange.com/questions/73083/how-doe...