Why will high accuracy GPS receivers be cheaper and smaller?
Today’s GPS dual-frequency receivers (L1/L2) can achieve a high level of accuracy (1 cm) in a short period of time, as little as a few seconds. But, they are expensive. An entry-level GPS dual-frequency receiver is a few thousand US dollars. The primary reason is because there is a limited number of companies that design GPS dual-frequency receivers for the geospatial industry, maybe a dozen or so. Why is there a limited number of manufacturers? The answer is because the original L2 was not an open signal. In the 1980s, some very smart engineers figured out how to utilize L2 (designed for military use only) in commercial receivers. When they developed those techniques, the companies were smart enough to patent them. There are so many patents in place that it makes it difficult for a new designer to enter the traditional GPS dual-frequency market, whether it’s surveying, machine control, GIS, or whatever. Unlike the original L2, L5 is an open signal. Its specification is published for a
