Single Aperture Night plus Polarization Compass

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Advanced Materials; Microelectronics; Integrated Sensing and Cyber OBJECTIVE: Celestial compasses used in handheld targeting systems are typically comprised of multiple optical channels for day (sun) and night (stars). During twilight (sunrise and sunset) the sun is low on the horizon and is potentially occluded and stars are not yet fully visible. Emerging sky polarization sensors can bridge the twilight gap and provide Soldiers accurate target azimuth. Combining the night (star) and polarization optical channels reduces system weight, complexity, and cost. DESCRIPTION: Celestial compasses have been in service for north finding on aircraft, vehicles, and handheld by Soldiers for decades and are typically configured as multi-aperture (day and night channels) devices with moveable filters. The current devices require nearly unobstructed views of the sky and have significant gaps in performance under twilight conditions. A newly available camera chip from Sony enables the night (star) channel and sky polarization channel to be merged into a single aperture with a common Focal Plane Array (FPA) and objective lens, while eliminating the need for moving parts. The integration of polarization into the night celestial camera extends the operational effectiveness in that North finding solution can be achieved when the sun is partially obscured by objects/clouds, is low on the horizon, and when it is slightly below the horizon when the sky is still too bright for stars to be observed. In addition to the increased availability, the Single Aperture Night plus Polarization Compass (SANPC) reduces the celestial system weight, decreases integration complexity, and lowers the unit cost. PHASE I: This topic is accepting Direct to Phase II proposals for a cost up to $2,000,000 for a 24-month period of performance. Proposers interested in submitting a DP2 proposal must provide documentation to substantiate that the scientific and technical merit and feasibility equivalent to a Phase I project has been met. Documentation can include data, reports, specific measurements, success criteria of a prototype, etc. (DIRECT TO) PHASE II: The outcome is to have the vendor design, demonstrate, and deliver two single aperture night plus polarization celestial compasses for use in a handheld targeting system. Interested companies must show that they currently have a foundational experience base into celestial compass systems and components, by having integrated a celestial compass into a targeting system (at least into a prototype targeting system). A working knowledge of the key aspects of celestial compass system such as optical design, digital image processing, computational algorithms, micro-processor, and other support electronics is a necessity in order to be considered for award. While the SANPC could have many applications, this SBIR has a specific potential application for incorporation into an army system. the SANPC must obtain azimuth solutions without reorientation The required azimuth requires high accuracy in night (star) mode and polarization mode. A design goal is to minimize or eliminate the time between when a polarization azimuth solution can last be obtained as the sun sets and moves further below the horizon, and when star-based azimuth solutions can first be obtained. Error Modeling and Testing of Celestial Compass Equipped Precision Targeting Systems, 3 November 2015, discusses error modeling/testing of night celestial compasses, but not polarization mode. This document is Distribution A (Approved for Public Release) but is not available in a public forum. A request for this document can be made by contacting nakia.s.ewing.ctr@army.mil. PHASE III DUAL USE APPLICATIONS: Civilian navigation: Compasses can be used as backup navigation tools when in a GPS-denied environment (e.g., sea shipping, air travel). Scientific Research: Provides remote sensing and time-keeping for geological surveys, animal observation, etc. Emergency Rescue: Enables redundant navigation tools in likely GPS-denied areas. REFERENCES: 1. https://doi.org/10.1242/jeb.204.17.2933 2. https://doi.org/10.1117/1.1847656 KEYWORDS: sky polarization; polarization filter; focal plane array; celestial compass; handheld targeting system; azimuth determination; forward observer