DON26BZ01-NV026 — Passive-Active Combo System for Unmanned Characterization of Littoral Environments
Award Maximum: $140,000 (Base) / $100,000 (Option) Period of Performance: 6 months (Base) + 6 months (Option) Phase Type: Phase I
OBJECTIVE: Develop a lightweight, integrated passive imaging and LiDAR system, deployable on an unmanned aerial platform for target detection, feature characterization, and bathymetry retrieval in littoral environments. The system should be light enough for deployment from a Group 2 (max. gross takeoff weight: 21 – 55 lbs.) unmanned aerial vehicle (UAV).
DESCRIPTION: Achieving and maintaining maritime dominance in the coastal battlespace requires the Navy and Marine Corps to have superior situational awareness. A key component of this dominance is the ability to rapidly characterize shallow, nearshore environments in real-time using agile, unmanned aerial platforms. To this end, a system is needed that provides (1) bathymetry retrieval; (2) detection and discrimination of underwater targets; and (3) characterization of the land-ocean interface (i.e., surface type, topography, and shallow-water bathymetry).
Current UAV-based shallow water and littoral zone characterization relies on either (1) passive imagers alone or (2) bathymetric LiDAR systems deployed on larger airborne platforms or in separate missions. While passive imagers effectively characterize surface features, bathymetric LiDAR is necessary for bathymetry retrieval and underwater target detection. Simultaneous deployment of both a high-performance passive imager and a bathymetric LiDAR on a Group 2 UAV is challenging due to payload weight limitations.
One potential solution is a system that can accommodate a passive imager and a dual-wavelength LiDAR that operates at two wavelengths – one where light penetrates deep into the water column and another with very little to no penetration into the water column – which can be used to effectively discriminate between LiDAR returns from the water surface and the substrate.
The system should provide rapid onboard processing of passive spectral and LiDAR data and real-time downlink of preliminary output to a ground station. The output should include a true-color composite of the target area, a topo-bathy map, a target detection map, and a terrain characterization map. The system should provide the above information for coastal waters up to 20 meters depth in moderately turbid waters (diffuse attenuation coefficient at 490 nm, Kd(490) ˜ 2-4 m-1).
PHASE I: Develop a preliminary observing system simulation experiment to simulate optical and spectral models for the combined passive imaging and LiDAR system. Perform sensitivity analysis of system performance for a range of design configurations under varying conditions of turbidity and optical complexity of shallow water environments. Conduct a feasibility study for the proposed system. Provide a report of the feasibility study and an initial layout of the proposed system design.
PHASE II: Develop the prototype based on optimal design configurations determined from the Phase I feasibility study. Finalize the approach for exploiting spectral information from the passive imager and combining spectral information with LiDAR returns for retrieval of three-dimensional bathymetry and characterization of the water column and the nearshore terrain. Limited demonstrations of the prototype are also required.
PHASE III DUAL USE APPLICATIONS: Upon successful demonstration of the prototype in Phase II, the system shall be flight-tested, developed into a commercial product against existing requirements of the Navy's Airborne Littoral Mine Detection System (ALMDS) and the Marine Corps' Standoff Explosive Detection System for operational coastal characterization and mine detection for transition consideration. Blue-green LiDAR serves environmental monitoring, underwater mapping, and marine ecology purposes.
KEYWORDS: Passive + active imaging system; topo-bathy LiDAR; mine detection; coastal characterization; unmanned aerial systems; nearshore bathymetry