Location is a fundamental service for mobile computing. Typical GPS receivers, although widely available, consume too much energy to be useful many applications. Observing that in sensing scenarios, the location information can post-processed when data uploaded server, we design Cloud-Offloaded (CO-GPS) solution allows device aggressively duty-cycle its receiver and log just enough raw signal post-processing. Leveraging publicly available such as GNSS satellite ephemeris an Earth elevation...

The optical communication system using pulse position modulation (PPM) and superconducting nanowire single-photon detectors (SNSPDs) has attracted considerable attention for deep space applications as it enables high speed data transmission at extremely low average signal power. deadtime of SNSPD is a critical factor in such systems because primarily affects the detection efficiency. This becomes even more crucial high-speed systems, where can span several symbol periods. We employ Markov...

Location is a fundamental service for mobile computing. Typical GPS receivers, although widely available navigation purposes, may consume too much energy to be useful many applications. Observing that in sensing scenarios, the location information can post-processed when data uploaded server, we design cloud-offloaded (CO-GPS) solution allows device aggressively duty-cycle its receiver and log just enough raw signal post-processing. Leveraging publicly such as GNSS satellite ephemeris an...

In this paper, a cascade acceleration feedback control (AFC) enhanced by disturbance observation and compensation (DOC) method is proposed to improve the tracking precision of telescope systems. Telescope systems usually suffer some uncertain disturbances, such as wind load, nonlinear friction other unknown disturbances. To ensure precision, an loop which can increase stiffness system introduced. Moreover, further we introduce DOC accurately estimate compensate it. Furthermore, analysis...

AbstractUnlike previous cases discussed, non-linear changes of refractive index in the photorefractive (PR) materials are governed by both linear and quadratic electro-optic (EO) effects simultaneously now. Here, evolution equations one-dimension spatial solitons resulting from EO effect presented firstly. Under appropriate conditions, our analysis indicates that bright, dark, gray can exist steady-state regime. Moreover, stabilities bright dark soliton propagation analyzed means beam...

The crosstalk performance of an arrayed-waveguide grating (AWG) multiplexer or demultiplexer is primarily caused by random optical phase errors introduced in the arrayed waveguides. Because layout waveguides on a wafer patterned via photomask through photolithography process, resolution has direct influence AWG. paper presents theoretical analysis error and other basic design parameters. Both calculation measurement results show that high-resolution (better than 25 nm) critical requirement...

In this paper, we numerically study the secrecy performance of free-space optical (FSO) system by considering different eavesdropping scenarios. More precisely, considered three possible scenarios for Eve: 1) Eve is between Alice and Bob; 2) Bob are in same receiving plane; 3) behind Bob. We adopt Málaga (M)-distribution channel to model atmospheric turbulence due presence link blockage while non-zero boresight pointing error path loss. To do so, obtain a novel probability density function...

Satellite platform vibration causes the misalignment between incident direction of beacon and optical axis satellite communication system, which also leads to instability laser link reduces precision system. So how simulate is a very important work in ground test systems. In general, device used for simulating vibration, but simulation effect not ideal because limited randomness. An approach reasonable, uses natural random process vibration. this paper, we discuss feasibility concept that...

This article presents a project to design robust robotic arm which can perform multifunctional tasks. The controller of the manipulator is based on Arduino mega 2560 Microcontroller. aim focus all axes lift, carry and unload objects at desired location. requires precise drive motion control that incorporate electric motors as system. Further experiments are done implement camera 3D vision system integrated with computer algorithm recognize object deformation spatial coordination deviation...

In satellite laser communication systems, accurate positioning of the beacon is essential for establishing a steady link. For satellite-to-ground optical communication, main influencing factors on acquisition are background noise and atmospheric turbulence. this paper, we consider influence turbulence in propose new locating algorithm beacon, which takes correlation coefficient obtained by curve fitting image data as weights. By performing long distance experiment (11.16 km), verified...

AbstractA number of new photorefractive materials, where refractive index changes in materials are simultaneously governed by both the linear and quadratic electro-optic effects, have been found recent decades. Here we first present a comprehensively theoretical study incoherently coupled spatial soliton pairs due to effects all four possible realizations: dark–dark, bright–bright, gray–gray, dark–bright. These owe their existence co-effects PR effect may be enhanced, weakened, or even...

The range accuracy of three-dimensional (3D) ghost imaging is derived. Based on the derived equation, relationship between slicing number and analyzed an optimum (OSN) determined. According to OSN, improved 3D algorithm proposed increase accuracy. Experimental results indicate that can affect significantly highest be achieved if system works with OSN.

The next generation of optical telescopes will provide high-resolution imaging celestial objects by using the aperture synthesis technique. To preserve quality image, fast corrections pistons among subapertures have to be applied, namely, co-phasing array. image-based method via an optimization procedure has been newly developed. Despite simplicity and strong commonality, when dealing with large piston errors, this correction is also faced a problem in which metric function easily falls into...

The centroid estimation of the beacon spot is crucial to pointing, acquisition, and tracking subsystem in inter-satellite optical wireless communication (IsOWC), especially for received very weak caused by a long link distance. In this work, we propose an accurate positioning method calculate such with low peak signal-to-noise ratio. proposed based on idea that uses normalized amplitude gray gradient enhance weights near center spot. Both comparative numerical simulation experimental...

We proposed a prediction algorithm for laser communication pointing, acquisition, and tracking (PAT) subsystems in order to further improve PAT accuracy reduce the effect of processing delay. In terms this algorithm, fading Kalman filter is employed, with observation noise obtained by gray value distribution images. Moreover, better fit dynamics target, two-stage dynamic model has been chosen as state transition filtering. addition, modified accommodating its form change time lag, thereby...

Cameras are common in the public building, and become one of popular sensors for indoor tracking. However, a camera will produce much data consume energy. Consequently, cameras, deployed large area, would have no overlapping field views (fovs). This leads to we cannot determine person's position unobserved area correctly, due unpredicted motion change, such as taking turns. Smart phone-based dead reckoning (DR) method is recently observed be an alternative filling these cameras' gaps realize...