SDI's “Best Ever” GPS/INS Tactical Grade System. The compact SDN500 combines latest generation quartz gyros, quartz accelerometers, high speed signal processing and a 48-channel Coarse/Acquisition (C/A) Code GPS receiver into a powerful, tightly coupled Guidance and Navigation System. The versatile instrument grade system delivers a reliable 3.9 meter Spherical Error Probable (SEP) GPS-aided accuracy. SDI’s proprietary Quartz MEMS Inertial Sensors maintain precision accuracy in the event of loss of GPS tracking. The low power SDN500 is designed for integrator and OEM use in the latest demanding smaller, more scalable system applications. The SDN500 is an ideal solution for critical applications in such areas as geo-surveying, unmanned air and ground vehicles, precision targeting and positioning, and establishes an excellent system solution in demanding commercial applications.