s We present a study of micro air vehicles (MAVs) with wingspans of 7.4 to 15 cm. Potential applications for MAVs, both military and civilian, are numerous. For most military applications, MAVs would be controlled by local users, operating covertly, to supply real-time data. This article focuses on a military surveillance application that uses either… (More)
—Optimal joint detection for interfering (nonorthog-onal) users in a multiple access communication system has, in general, a computational complexity that is exponential in the number of users. For this reason, optimal joint detection has been thought to be impractical for large numbers of users. A number of suboptimal low-complexity joint detectors have… (More)
NASA is presently overseeing a project tocreate the world’s first free-space lasercommunications system that can be operated overa range ten times larger than the near-earth rangesthat have been demonstrated to date. To be flownon the Lunar Atmosphere and Dust EnvironmentExplorer (LADEE), which is planned for launch byNASA in 2012, it will… (More)
Introduction: The National Research Council report The Scientific Context for Exploration of the Moon (SCEM) lists studies of the pristine state of the lunar atmosphere and dust environment as one of eight major priorities for future lunar science missions. The Lunar Atmosphere and Dust Environment Explorer (LADEE) was developed to address this goal. LADEE… (More)
The Lunar Laser Communications Demonstration (LLCD) is an ongoing project to demonstrate a high-rate, bidirectional optical communications link between a lunar satellite and an Earth-based ground terminal. The optical downlink operates at data rates up to 622 Mbps and employs photon counting array receiver technology. While the use of a 16-PPM modulation… (More)
In this paper we present a design for a photoncounting optical receiver—based on superconducting NbN nanowire detector arrays—that will be employed in the ground terminal for the NASA Lunar Laser Communications Demonstration. The ground receiver is designed with four, 40 cm apertures, each coupled to a novel multi-mode polarization-maintaining… (More)
We designed and successfully demonstrated a multimode fiber-coupled photon-counting optical receiver at 1550 nm for the Lunar Laser Communications Demonstration that achieves low coupling loss through atmospheric turbulence without requiring adaptive optics.