Shackleton Energy has more than 20 years of operational experience in the design, integration, test, and fielding of advanced guidance, navigation, and control (GN&C) systems.  SEC specializes in multi-stage Kalman filter systems that employ a wide array of navigational inputs - -from GPS, IMU, FOG gyros, ring laser gyros, MEMS gyros, digital compass, velocity, doppler, pressure, slant range and heading, optical, laser radar, lidar, acoustic, altimeters, SAR, radar, and more.  We design highly redundant systems for survival in hostile environments.  Our design team handles all levels of implementation from desktop and laptop prototyping systems to industrial board stacks and custom embedded systems including ASICs and FPGAs.  We design our own embedded systems.   We specialize in the tight integration of large intelligent sensor networks driving distributed intelligent, redundant actuator systems (thrusters, engines, reaction control, attitude control) and have an extensive library of debugged real-time autonomous system control code for operation of free flying systems operating in all six degrees-of-freedom (x,y,z, roll, pitch, yaw).