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Propagation and performance analysis for a 915 MHz wireless IR image transfer system / Propagation and performance analysis for a 915 MHz wireless infrared image transfer systemFelekoglu, Oktay. 06 1900 (has links)
A 915 MHz wireless IR image transfer system, comprised of an IR-160 Thermal Camera and MDS iNet 900 transceivers, was assessed for image transfer capabilities in different environments. Image transfer through natural and artificial obstructions, the capability of transferring images under urban environments, and an exploration of interference issues associated with RF communication links were investigated in detail. Concrete, wood, various construction materials, and building walls were examined to assess indoor propagation capabilities. Data transmission through random trees, buildings, foliage under various atmospheric conditions is also evaluated for outdoor system capabilities. A maximum free space range for acceptable IR image transferring is determined as 23 miles for line of sight (LOS). Non line of sight (NLOS) urban environment measurements revealed that urban path loss (15-60 dBm) is highly dependent on antenna orientation and obstruction geometry rather than the T-R separation distance.
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Propagation and performance analysis for a 915 MHz wireless IR image transfer system /Felekoglu, Oktay. January 2005 (has links) (PDF)
Thesis (M.S. in Applied Physics)--Naval Postgraduate School, June 2005. / Thesis Advisor(s): Richard M. Harkins, Gamani Karunasiri. Includes bibliographical references (p. 77-78). Also available online.
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Integrated attitude determination system using a combination of magnetometer and horizon sensor dataMaass, E. (Eanette) 12 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: A different approach of employing attitude sensors with incomplete measurements
in an attitude determination system is investigated. The amount of available attitude
sensors on small satellites are limited, and the failure of sensors can be fatal
when accurate attitude determination is necessary. The problem with sensors
with incomplete measurements is that they must be used in combination with
other sensors to obtain three dimensional attitude information. The aim is to
enhance the possible number of sensor combinations that can be employed, in an
attempt to improve the ability of the attitude determination system to tolerate
sensor failures.
An alternative sensor structure consisting of a magnetometer and two horizon
sensors is presented. A method to obtain vector observations of the attitude
from a combination between magnetometer and horizon sensor measurements is
derived and tested. A full state Extended Kalman Filter is used to determine
the satellite's attitude, attitude rate and disturbance torque from these vector
observations.
A second Extended Kalman Filter structure, using only magnetometer measurements,
is implemented. The magnetometer Extended Kalman Filter and the
horizon/magnetometer Extended Kalman Filter are integrated to obtain a single
Extended Kalman Filter structure to determine the satellite's full attitude state.
Integration is done by switching between the different pairs of vector information.
A systematic analysis of the integrated filter's dynamic behaviour during
the switching stages is done by means of a series of case studies. / AFRIKAANSE OPSOMMING: Die gebruik van oriëntasiesensore met onvolledige metingsdata in oriëntasiebepalingsstelsels
is ondersoek. Slegs 'n beperkte aantal oriëntasiesensore is beskikbaar
op mikro satelliete. 'n Foutiewe sensor kan dus noodlottig wees wanneer akkurate
oriëntasiebepaling nodig is. Die probleem met sensore met onvolledige metingsdata
is dat dit in sensor kombinasies gebruik moet word om drie dimensionele
oriëntasieinligting te verkry. Die doel is dus om die moontlike aantal sensor kombinasies
sodanig te vermeerder dat die oriëntasiebepalingsstelsel beter bestand
sal wees teen moontlike sensor falings.
'n Alternatiewe sensor struktuur, bestaande uit 'n magnetometer en twee horison
sensore, is ondersoek. 'n Metode vir die verkryging van 3-as oriëntasie inligting
vanaf 'n kombinasie van magnetometer en horison sensor metingsdata is afgelei
en getoets. 'n Vol toestand uitgebreide Kalmanfilter is gebruik om the satelliet
se oriëntasie, oriëntasie snelheid en versteurings draairnoment vanaf die vektor
observasies af te lei.
'n Tweede uitgebreide Kalmanfilter struktuur, wat slegs magnetometer metingsdata
gebruik, is geïmplementeer. Die magnetometer filter en die horison/magnetometer
filter is geïntegreer sodat een uitgebreide Kalmanfilter struktuur volle
oriëntasie inligting kan aflei vanaf verskillende pare vektors met oriëntasie inligting.
Integrasie is gedoen deur te skakel tussen die verskillende vektorpare. 'n
Sistematiese analise van die geïntegreerde filter se dinamiese gedrag gedurende
die oorskakelingstye is gedoen deur middel van 'n reeks gevallestudies.
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Thin film piezoelectric elements for active devicesMcGinn, Christine January 2022 (has links)
Piezoelectric materials have had widespread application since their discovery both in bulk crystal and thin film applications, but thin film piezoelectrics have unlocked key applications like acoustic filtering and energy harvesting. [1] This work investigates a small subset including energy harvesting, multifunctional nanocomposites, acoustic wave resonators, and gravimetric and infrared sensing. Electroactive polymers such as PVDF-TrFE have a unique combination of characteristics including a high dielectric constant, piezoelectricity, pyroelectricity, biocompatibility, and mechanical flexibility. [2, 3, 4, 5, 6] This unique combination gives them a wide potential application space including energy harvesting, biomedical devices, drug delivery, flexible electronics, and tactile sensing.
[7] In recent years, there has been significant work investigating potential composite materials based on electroactive polymers and nanoparticles. [8] This interest has been primarily driven by the increased commercial availability, tunability, and available functionalities of nanoparticles. In this work, nanocomposites of PVDF-TrFE, barium titanate (BTO), and europium barium titanate (EBTO) are investigated. EBTO is an optically active material which can add optical functionality to these active polymer composites. [9] Acoustic wave resonators including bulk acoustic wave resonators and surface acoutstic wave resonators are widely used for front end filtering technologies, but their high quality factor, small size, and low power makes them good candidates for sensing technologies. [10, 11, 12] In this work, FBARs are applied to VOC sensing and infrared sensing sucessfully.
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Multisensor track initiation method that addresses the missing measurement problemPawlak, Robert James 19 June 2006 (has links)
A method for integrating multisensor data for the purpose of track initiation using horizon infrared and radar data is proposed. This multisensor track initiation (MSTI) method extends contemporary data fusion techniques so as to address the problem of missing measurements. The missing measurement phenomenon occurs due to a variety of reasons, the foremost of which is variation in sensor detection performance due to environmental factors.
The proposed MSTI method requires only the results of spatial feature tests that are performed on sensor data sequences. The formation of data sequences and the derivation of feature tests to integrate horizon radar and infrared data of differing resolutions is addressed.
Results are presented that detail the performance of the MSTI technique when operating on simulated data. It is shown that the statistical performance of the MSTI technique is better than or equal to that of the AND algorithm for a representative set of scenarios. The sensitivity of the MSTI method to variations in assumed feature test and data sequence statistics is also addressed. / Ph. D.
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