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Free-Space Optical Communications: Light Detection and Ranging Enhanced Data Delivery


OBJECTIVE: Using a single laser source, demonstrate the capability to collect and transmit LiDAR (Light Detection and Ranging) data via free-space optical communications in an effort to expedite the delivery of tactical topographic information. DESCRIPTION: LiDAR, or Light Detection and Ranging, is presently the fastest developing mapping technique in the geospatial sciences and is an invaluable asset to the Department of Defense (DoD). However, unless the expedited transmission of data is addressed, the capture, processing and delivery of LiDAR-generated tactical topographic products will not be possible in a manner advantageous to planners, field commanders, and ultimately the soldier. Over the past 10 years, as laser scanning technology has developed, significant milestones have been achieved in efficiency of the collection of range points for mapping. For example, the time to collect 1 million range points has gone from 15 years using traditional survey methods, to 1.5 years using analytical stereo photogrammetry, to 6.7 seconds using a LiDAR operating at a Pulse Repetition Frequency (prf) of 150 kHz. Recently, with the development of flash LiDAR technology, full-waveform recovery, and Geiger-mode detection array-based systems, LiDAR is evolving from a topographic mapping-only system into a truly active remote sensing capability. As a remote sensing system, however, the tactical and terrain analysis benefits of LiDAR have yet to be fully realized, especially as the technology moves away from analog detection and processing (i.e., monopulse detection) to waveform digitization (i.e., full characterization of a target). As LiDAR technologies become increasingly capable of delivering tens or even hundreds of returns per pulse, the utilization of this data will require novel delivery strategies and algorithmic processing approaches to make this information available to the Warfighter on an operationally-relevant timeline. To address the data capture and delivery issue, this SBIR solicitation seeks to explore the potential of enhancing LiDAR capabilities by using free-space optics (FSO) to deliver data using the same laser source that was used to acquire the data. Presently, LiDAR acquisitions require anywhere from 48 hours to 14 days for meaningful product generation. This is typically based on first acquiring the data and either: 1) disk removal and transport to a processing facility or 2) radio frequency (RF) transmission of data in small packages to a processing facility. The recent adaptation of a free-space optics approach to data streaming is now moving data at a potential 10 Gbps or more providing faster through-put for processing. Furthermore, the advances in adaptive optics and real-time correction algorithms will provide for data continuity and quality control. While this capability development is being explored for the transmission of synthetic aperture radar (SAR) data, it has yet to be accomplished using the active source of a LiDAR system. The development of a dual-purpose laser system for data capture and delivery is considered to be a high risk / high reward technical obstacle. PHASE I: Determine the technical feasibility of using short-wave infrared lasers, inherent to present-day LiDAR collection systems, as dual-use data transmission devices. Develop an innovative conceptual design which addresses laser attributes (e.g., wavelength- such as 1550nm, pulse rate, propagation, atmospheric effects such as scattering, absorption and scintillation), as well as payload / power issues in the adaptation of collection lasers to transmission lasers. This research should also present information on a realistic data streaming rate potentially achievable with such a conceptual system. Potential partners with regards to existing LiDAR collection systems should be identified. PHASE II: Leveraging the results from Phase I, develop a prototype adaptable to a current theater-operational gimbaled LiDAR (preferably airborne system). Provide practical implementation demonstrating the acquisition of LiDAR data over a variety of topographies, and the subsequent pre-processing and data telemetry via free-space optics (using the same laser source) to transmit the data to a processing or collection facility. Address data continuity and quality control capabilities/limitations. PHASE III: The expedited, FSO-based delivery of LiDAR data (via a novel, dual-use laser collection/transmission capability) would benefit both the mapping and tactical communities. From a commercial perspective, such advancement in geospatial data delivery would aid emergency response and disaster relief efforts. Technology transition would occur as integration into an existing LiDAR mapping system, and military applications would include expedited battlefield visualization and urban warfare planning.
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