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In this paper, an earth observation Microsatellite communication system is proposed. The spacecraft will revolve in a sun-synchronous retrograde circular orbit. Therefore, it is equipped with two banks of cameras giving a total of 600km field of view at 30 meters spatial resolution in three spectral bands, the Red, Green and Near Infra-Red. The communication sub-system is designed to support the mission...
This paper gives the background and details of the Atlas V Aft Bulkhead Carrier to be flown on the National Recoinnassance Office Launch 36 with the Operationally Unique Technologies Satellite Auxiliary Payload. The CubeSats included are from a number of labs, universities and government entities for the purpose of technology demonstration, science experimentation and operational proof of concepts...
Absorption and emission of gases in the submillimeter wavelengths is currently exploited for laboratory spectroscopy as well as remote astronomy and limb sounding. We are developing a field-ready submillimeter spectrometer that will enable in-situ sensing with a goal for characterization of biogenic gases and life tracers. Progress toward a field-ready instrument includes: the development of a brass...
In this paper a new form of random interleaver for turbo coding is introduced. This new structure is based on the probability distribution of the channel statistic model, instead of the uniform probability distribution. We use the normal (Gaussian) and Rayleigh probability distribution in accordance with the channel type, and compare them with dithered golden interleaver. For the simulated cases good...
When the radar transmits electromagnetic waves, the target characteristics can be extracted from the received echo signal. During the reception process, the radar carrier frequency will be shifted due to the Doppler effect of moving targets. If a specific target makes any vibration or rotation, an induced frequency modulation on the received echo signal will be occurred generating side-bands around...
In monopulse radar target tracking systems, estimation of the radar cross section (RCS) of a given target under track is important for many reasons that include efficient waveform selection and revisit rate. In practice, for Rayleigh (Swerling I and II) targets, the RCS is calculated assuming an exponentially distributed observed SNR and using the parameter estimator for that distribution. However,...
Low data rate communication links require less power to close the link; however as the data rate becomes very low given a fixed Eb/N0, phase cycle slips due to infrequent carrier loop updates in the presence of oscillator phase noise become problematic. Assuming coherent demodulation, a cycle slip will cause loss of sync which is unlikely to be recovered until a new frame header is received. This...
Presented in this paper is a very wide stopband filter of reduced size, improved stop-band rejection, and good input-output return loss for Radio Altimeter applications. To improve the stopband rejection three and four different types of stepped-impedance resonators (SIRs) are used. To further improve the wideband rejection, a notch filter is kept at the output of the filter. The simulated results...
In this paper, a novel hyperspectral image clustering procedure, which is based upon the Fully Constrained Least Squares (FCLS) spectral unmixing method, is proposed. The proposed clustering method consists of three major steps: endmember extraction, unmixing procedure and hardening process via the winner-takes-all approach. To estimate the optimal number of endmembers, instead of using the background...
We propose a model-based approach to provide “open-loop” control, or precise go-to capability, for piezo actuated deformable mirrors (DMs) used in adaptive optics. Our DM model consists of a two-dimensional, linear partial differential equation known as the thin plate equation to describe the DM facesheet which is coupled to nonlinear scalar ordinary differential equations to describe the hysteretic...
A prototype virtual Ethernet driver (BPTAP) has been written which runs atop the ION (Interplanetary Overlay Network) implementation of the DTN (Delay/Disruption Tolerant Network) protocol. This driver has the potential to expedite DTN deployment by providing a transition mechanism for legacy IP (Internet Protocol) applications to run alongside delay and disruption tolerant applications in future...
Air Traffic Control1 Radars (ATCRs) are being used by many countries to enhance air situational display used by Air Traffic Controllers for better air space management and safety of aircraft. Like all others radar systems it has its advantages and disadvantages in terms of performance, maintenance difficulties and cost. In spite of its number of users, literature on its defect trend analysis is almost...
In terms of time and budget, integration is a significant time-consuming component of spacecraft development. While many useful COTS spacecraft components are available, interfacing and controlling these components in an integrated satellite system remains a complex engineering task. The Stan-ford/Cal Poly CubeSat and Poly-Picosatellite Orbital Dispenser (PPOD) standards have begun to standardize...
RF photonic techniques can be used to extend operating frequencies and bandwidth of mission communications and sensing systems. Photonic links inherently cover wide frequency bandwidths and optical modulators and detectors have been demonstrated that operate up to 100 GHz. This paper presents a photonic method for tunable high frequency carrier generation and wideband tunable RF frequency conversion...
Parametric cost estimating tools and processes often estimate cost totals without spreading them across a project schedule by year. Government oversight and constrained budget profiles make understanding cost and cost drivers on an annual basis essential in order to see the direct effects of changes to cost profiles. An efficient, data-driven, transparent approach to cost spreading that can be calibrated...
At the Jet Propulsion Laboratory, Mission Operations software places unusual demands on its developers and users that require new solutions. Scientists are often faced with the difficult task of interpreting the sizes and relative positions of objects in an environment when viewing an image of the environment on computer monitors or prints. We have created an immersive visualization environment, known...
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