Localization is critical for autonomous vehicles, sea and transport guidance, and present day military missions. When GPS is denied or spoofed, current navigational devices can become highly inaccurate. For instance, and IMU heading estimate will drift, accumulate error, and degrade the position over time.

The Sky Polarization Azimuth Sensing System, SkyPASS®, provides an inexpensive method for measuring absolute orientation in a GPS-denied environment. The system is passive and well suited for any man or vehicle platform to provide mission critical navigational localization accuracy regardless of GPS accessibility.

Far Target Locator



There are four variables that must be defined in order to determine the location of a target on Earth: azimuth, elevation, self-position, and distance. The largest source of target location error in existing systems is to accurately determine azimuth. In most cases, azimuth errors in the guidance of man-portable weapon systems would lead to failure of target acquisition and destruction. Currently available high-accuracy azimuth sensors are expensive, bulky, heavy, power hungry, and require up to 4 minutes for setup. Digital magnetic compasses have long been an inexpensive means for azimuth determination, but they are hindered by magnetic interference and offer only marginal accuracy.

The Sky Polarization Azimuth Sensing System, SkyPASS®, is a high-accuracy, low SWaP-C solution for determining azimuth within 2 mills for any platform requiring accurate heading information including man-portable weapon systems. SkyPASS is not hindered by many of the operational limitations seen in the current azimuth sensing methodologies. SkyPASS provides accurate azimuth in real-time, does not require leveling, and can even assist in determining orientation when GPS is unavailable.

SkyPASS Features & Benefits


  • Less than 2-mil heading accuracy
  • Calculates absolute heading
  • Low SWaP
  • No start-up delay
  • No set up or leveling
  • Not affected by magnetic disturbances
  • Driftless
  • Spoof-proof
  • Planes
  • UAVs
  • Ships
  • AUGVs
  • Munitions
  • Autonomous Robots
  • Far Target Locator

How It Works

Celestial compass

Sky polarization is an upper atmosphere phenomenon observable from any point on Earth or from any aerial platform. In the diagram, the time of day is shown at the top of each polarization map, the Sun is shown as a small, yellow disc, and the center of each plot is zenith. Using advanced algorithms and optics, SkyPASS is able to detect and decipher the polarization map of the sky to compute highly accurate heading.


It is important to note that sky polarization sensing is not affected by magnetic disturbances, does not require leveling or field calibration, and can provide an instantaneous answer. When compared to celestial sensing methods, like Sun or star trackers, SkyPASS outperforms because it can operate in a variety of cloud conditions, at solar noon, and at sunrise/sunset. The SkyPASS sensor can be produced at a much lower cost than competing technologies. A celestial method that can operate at sunrise/sunset, at solar noon, and in a variety of cloud conditions, SkyPASS is the next step forward in orientation sensing. It has also been tested as an add-on to the Far Target Location (FTL) systems that enable the warfighter to determine target position with a very high degree of accuracy. The system has also been attached to the exterior of aircraft to determine heading accuracy.