Metalens Solar Compass (MLSC)

A Celestial Compass provides rapid and accurate non-magnetic azimuth information for precision handheld targeting systems used by Forward Observers. Typically, solar compasses utilize a multi-element telecentric fisheye lens. To meet the azimuth accuracy requirements, individual lens elements must meet and maintain centricity, spacing and tilt specifications and provide micrometer-level line-of-sight (LOS) stability during environmental cycling over its lifetime. The high stability telecentric fisheye lens is large, heavy, and complex. It is the single most expensive component in a solar compass. Metalens technology provides a basis for development of miniaturized imaging systems containing fewer elements with increased stability. JHU/APL recently developed a metalens structure with most of the functionality of a telecentric fisheye lens. A metalens will greatly simplify solar compass design, while still performing as well or better than traditional telecentric fisheye lenses because all the tolerances between multiple individual lens elements have been eliminated. With the use of a metalens, size, weight and cost of the solar compass will be reduced. It is expected that at realistic military production volumes, unit price of metalenses will be in the range of a few hundred dollars.Proposed program will develop and demonstrate the 1st metalens-based solar compass for Far Target Location  (FTL) systems. Under this program the following results will be obtained. A solar compass using a metalens will be designed, fabricated, calibrated and field tested. The field-of-view (FOV) of the metalens will be increased to cover an entire hemisphere. Time to celestial navigation solution will be reduced by a factor of 3x using FPGA processing. Availability of accurate celestial solutions during daytime will be increased because the metalens solar compass can provide accurate azimuth readings for solar elevations up to 80°. The metalens solar compass design will provide a “drop in place” replacement for solar compasses in Army Joint Effect Targeting System (JETS) units comprising traditional telecentric fisheye lenses. Using proprietary technologies developed at Trex, the metalens solar compass prototypes  developed under this program will meet all required mil-spec temperature and shock & vibration requirements. This will accelerate transition of metalens solar compass technology to Army Programs-of-Record. Trex’s team possesses more than two decades of experience in celestial navigation technology. This will mitigate technical risk.