This paper focuses on problem of locating IoT devices in open area. There are basically two location methods from the IoT implementation point of view: active and passive. Active methods work great if we have opportunities and resources to implement data exchange and location systems in usually small IoT devices. Passive methods could be more efficient on calculation and hardware basis for locating devices with their own low power radio signal, but without need of data transfer. Passive methods are discussed in this paper. Target is successfully reached when observer can locate object in reasonable distance. Another factor is overall cost of the system. Low cost software defined radios in combination with embedded computing platforms can capture signal and pass it to cloud services. Data processing is live operated to present location information with small latency. Two concepts of passive measurements are presented: measurement of amplitude and arrival time differences of signals obtained at three receivers. These two methods combined can possibly give opportunity to achieve results with a sufficiently small measurement error.
This paper focuses on numerical analysis of the technological imperfections of the Bragg grating inscription process in the fiber. For such purposes, a Rouard method that allows for simulating a Bragg gratings section-by-section has been employed. The analysis presented in the paper includes considerations on the period instability of the grating together with variance of induced by UV exposure changes of the refractive index. As a result, an impact of these imperfections on the spectral responses has been examined, for both Gauss and Johnson distributions. The general motivation of this work is a proposition for novel process of the phase mask fabrication, what is also described in the following paper.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.