Field Testing of a Quad Rotor Smartphone Control System

With recent regulatory efforts to reduce restrictions placed on the operation of Micro Air Vehicles (MAVs) in the United States, it is likely that in the next few years, these vehicles will become commonplace in the commercial marketplace as they are in military environments. In order to reduce the barrier to entry for operations of MAVs, customers of these systems will require ease of operation as well as minimal training time in order to reduce costs. To this end, a smartphone application was developed to control a quadrotor remotely in the exploration of an unknown environment, and tested for users with only three minutes of training. Initial motion capture room tests produced encouraging results for localization and target identification tasks, however, such environments are inherently artificial and the extensibility of such results is limited. A follow-on outdoor field study was conducted in order to compare the indoor and outdoor results and to assess operator performance in a realistic environment. Performance on the outdoor localization tasks was comparable to the indoor study, however, participants generally performed slightly worse on the target identification task in the outdoor experiment, attributed to camera image quality and GPS localization issues. Other issues such as wind and flight safety considerations are discussed.The Office of Naval Research and the Boeing Company sponsored this research

Multi-messenger Observations of a Binary Neutron Star Merger

International audienceOn 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of $\sim 1.7\,{\rm{s}}$ with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg(2) at a luminosity distance of ${40}_{-8}^{+8}$ Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 $\,{M}_{\odot }$. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at $\sim 40\,{\rm{Mpc}}$) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position $\sim 9$ and $\sim 16$ days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta