wave phases correctly. This enables the mobile devices to calculate their position relative to the base station with a high degree of precision. Base stations can be temporary or permanent and many devices, up to 20km away, can use the same base station for their corrections.A Reach device can be used as a mobile client, or as a base station if it is stationary and its coordinates are known. This way, a system of two receivers connected to one another using wi-fi Internet access or radio communications can calculate precise coordinates even if no other DGPS base stations are available.The position of base stations can be measured accurately using commercially or freely available correction services in many countries, including the Continuously Operating Reference Stations (CORS) network. If the precise location of the base station is not known, the mobile clients can still consistently and accurately calculate their position relative to the base station.PylonGPS is developed by Charles West, a researcher from NC State University who works to create a service that would make it simple to stream the GPS correction data from Reach RTK base stations to anyone who wants it over the Internet. Emlid hopes to incorporate this in a future software release so that users can share the corrections from their base stations, and make more accurate positioning more accessible to everyone.Developing ReachThe founders of Emlid previously integrated survey-grade GPS receivers into autopilots and mapping systems, costing many thousands of dollars, for a major commercial manufacturer. We cant completely replace those professional systems, said Vereninov. They perform better in challenging environments and can have larger distances from rover to base. But we are bringing a similar precision at a drastically lower price point.The idea for Reach came when Emlid sampled the RTKLIB toolkit developed by Tomoji Takasu and supported by the open source community (the toolkit has a BSD License). We were using it to postprocess data from flights, but we quickly saw its potential, said Vereninov. If we wanted to do real-time positioning, though, we needed to have the receiver connected to a PC at all times. For surveying work, you use a laptop, for example, but thats too heavy for a drone or other small device. We had the idea to use an Intel Edison single board computer, which can replace the laptop in this application, so RTKLIB runs on the GPS receiver itself.Positioning accuracy with the help of Reach. Red dots show normal GPS precision in good conditions. Green dots show positions provided by Reach in RTK mode. The receiver was kept stationary so in an ideal situation there would be no deviation. The graph shows that Reach provides positions with less deviation, because the green dots are much closer together. The numbered dots are the most recently plotted points in this real-time graph. Please note the scale.A look inside ReachThe Reach hardware platform consists of three components: an Intel Edison computer running a custom, Yocto-built, Linux operating system and RTKLIB; a U-blox GPS-receiver; and an external Tallysman antenna, which plays an important role in enabling accurate