The term can refer both to the generalized technique, as well as specific implementations using it. It is often used to refer specifically to systems that re-broadcast the corrections from ground-based transmitters of shorter range. For instance, the United States Coast Guard runs one such system in the US and Canada on the longwave radio frequencies between 285 kHz and 325 kHz. These frequencies are commonly used for marine radio, and are broadcast near major waterways and harbors. Australia runs a similar service for land and air navigation, broadcasting their signal on commercial AM radio stations.The European Geostationary Navigation Overlay Service, Japan's Multi-Functional Satellite Augmentation System, Canada's CDGPS and the commercial VERIPOS, StarFire and OmniSTAR systems are all Satellite Based Augmentation Systems
maritime service provides 10 meter (2 dRMS) navigation accuracy, integrity alarms for GPS and DGPS out-of-tolerance conditions within 10 seconds of detection, availability of 99.7% per month, coastal coverage to the continental United States, the Great Lakes, Puerto Rico/US Virgin Islands, and selected portions of Alaska and Hawaii.