ARRAY BASED FREE SPACE OPTIC SYSTEM FOR TACTICAL COMMUNICATIONS

Free-space optical (FSO) communications offer a resilient and flexible alternative communications medium to current radio technologies, which are increasingly threatened by our peer adversaries. FSO provides many advantages to radio technologies, including higher bandwidth capability and increased security through its low probability of detection (LPD) and low probability of interception (LPI) characteristics. However, current FSO systems are limited in range due to line-of-sight requirements and suffer loss from atmospheric attenuation. This thesis proposes the use of arrayed optical emitters for FSO communication by developing a link-layer protocol that leverages the inherent error correction of quick response (QR) encoding to increase bandwidth and overcome atmospheric loss. Through the testing of a system built with commercial-off-the-shelf equipment and a survey of current optical transmitter and receiver technology, this link-layer protocol was validated and estimated to provide similar data rates to current single emitter FSO systems. Various limitations were discovered in the current structure of the protocol. Future work should be conducted to correct inefficiencies in the QR encoding format when applied to a transmission medium. Additionally, technological advancements in hardware systems, including the large-scale production of VCSELs and faster high-speed cameras, must be achieved before such an FSO would be viable for large-scale use.http://archive.org/details/arraybasedfreesp1094559655Captain, United States Marine CorpsApproved for public release; distribution is unlimited

Choice set generation for large-scale cycling networks

This work presents a sensitivity analysis of the Breadth First Search on Link Elimination (BFS-LE) algorithm in the context of choice set generation for the modelling of cyclists' route choice. Compared to motorised traffic, modelling cyclists typically requires much more complex networks due to the unrestricted nature of how they can move through urban space. In comparison to other methods, the literature indicates that the BFS-LE algorithm performs exceptionally well in terms of computational cost hence making it particularly well suited for applications on large-scale cycling networks. As cycling is becoming an increasingly relevant mode due to the urgent need to decarbonize urban transport, there is a need for up-to-date bicycle route choice models, specifically for designing cycling infrastructure. This study is part of a wider effort of making the BFS-LE algorithm more accessible to a larger community by integrating it into the MATSim framework and in developing a state-of- the art route choice model for cyclists. Additionally, we present findings useful to modellers aiming to fine-tune the BFS-LE algorithm to their use-case

Route choice modelling for cyclists on dense urban networks

This paper presents the results of route choice models for cyclists in the city of Zurich. The data includes approx. 4400 cycling trajectories, including approx. 850 from e-bikes. The network is sourced from OSM and the choice set generation is based on a modified version of the BFSLE algorithm. We present descriptive statistics as well as the model results which specifically point out the difference between regular and e-bikes. We provide results of both a simple MNL and a more complex mixed Logit, both estimated in Value-of-Distance (VoD) space, and both suited to directly derive VoD indicators. The results show anticipated effects for cycling infrastructure, speed limits, traffic signals, gradients and traffic volumes. Numerous socio-demographic interaction effects shed light on the taste heterogeneity

Route choice modelling for cyclists on urban networks

This paper presents the results of route choice models for cyclists in the city of Zurich. The data includes approx. 4400 cycling trajectories, including approx. 850 from e-bikes. The network is sourced from Open Street Map (OSM) and the choice set generation is based on the breadth-first search on link elimination (BFSLE) algorithm. We present descriptive statistics and model results which specifically point out the difference between regular and e-bikes. We provide results of a simple path size Logit (PSL) and a more complex mixed PSL, both estimated in Value-of-Distance (VoD) space, and both suited to directly derive VoD indicators. The results show anticipated effects for cycling infrastructure, speed limits, traffic signals, gradients and traffic volumes. Numerous interaction effects shed light on the taste heterogeneity.ISSN:0965-8564ISSN:1879-237

A Zurich pedestrian route choice model based on BFSLE choice set generation

With growing interest for sustainable transport modes, city governments are transforming urban spaces to better cater to pedestrians. To make worthwhile infrastructure adaptations, the behavioral preferences behind pedestrian route choice decisions have to be understood. Sets of alternatives are created for 922 GPS tracked walking trips within the city of Zurich using the breadth first search with link elimination algorithm (BFSLE). Shortcomings of the algorithm in a pedestrian mode context and with high-resolution networks are illustrated and the algorithm is adapted accordingly. The choice sets serve as input for a simple route choice model estimation with interaction parameters. Preliminary results suggest preferences for shorter routes with low gradients and high number of amenities. While the model results are not considered robust due to a small data sample, the recommendations for adapting the BFSLE algorithm prove promising for future implementations

NPS-19-F044 Low $WaP trained Neural Net for nLoS LPI LPD applications

CRUSER TechCon 2018 Research at NPS. Wednesday 2: Teaming. Includes supplementary materialLeveraging Machine Learning for Optical MIMO laser QR signaling – Movidius Fathom / Intel Neural Compute Stic

NPS-19-F044: Low $WaP Trained Neural Net for nLoS LPI LPD Applications

Naval Research Program PosterNPS-19-F044