Thomas Ostertag

Measurement of mobile radio propagation channel in ruins

Within a running project, I-LOV1, wireless communication channel model for mobile communications is developed based on measurements in reconstructed disaster and salvage scenarios. Due to complex environment in ruins, great multipath interference can take place, which strongly impacts communication quality and localization accuracy. Besides numerous measurements investigated in environments such as urban, outdoor-to-indoor or indoor, only a few are in ruins. This paper presents the first results of channel propagation measurements under collapsed buildings at GSM 900 and GSM 1800 bands. Measurement campaigns were performed in two typical collapsed structures: stratified and chaotic rubbles. The statistical properties of path-loss (PL) and RMS delay spread (DS) are reported.

Open parallel-plate dielectric resonator for passive torque sensing

This paper presents a novel torque sensing concept, based on resonant perturbation of an open parallel plate dielectric resonator. When torque is applied to the shaft, the air gap between the parallel plates fixed on a clamp system is changed, which in turn shifts the frequency of the dielectric resonator. Finite Element Method (FEM) simulations using HFSS (ANSYS®) and experimental results regarding the effects of air gap variation on the TE01δ mode in the 2-3 GHz range are presented to prove the sensing concept.

A parallel plate dielectric resonator as a wireless passive strain sensor

This paper presents a wireless passive strain sensing concept that functions by detuning a dielectric resonator. It is shown how a high Q resonator functions as a wireless passive sensor when correctly matched with an antenna. Finite element and analytical models are compared with experimental data and the sensor cross sensitivity with respect to temperature and humidity are also explored. The sensitivity of the resonance frequency to the strain, temperature and humidity is measured to be 51.6 ppm/μm, 10.09 ppm/K and -0.65 ppm/% respectively.

New technologies for the search of trapped victims

This paper presents the results of a German research project aiming at improving Urban Search And Rescue (USAR). It comprises two wireless search technologies for the detection and localization of trapped or buried unconscious victims and auxiliary assisting technologies. Victims can be localized through their cellular phone (GSM) if it is active, but it might be out of order. Results detecting inactive phones are presented. However, with this technology a victim without cellular phone cannot be detected. In this case, a ground-penetrating, continuous wave radar can be used that is as well presented. A channel model for estimating signal disturbances in debris between victim and receiving antenna is proposed that aims at improving the accuracy of these technologies. Furthermore, the I-LOV system assists decision-makers by a mobile IT-system called FRIEDAA that allows gathering, processing, and representation of relevant information such as search results and personnel locations in real time. Therefore, infrastructure and inertial sensor based personal localization systems are presented.

Self-synchronized energy efficient event detection with wireless sensor networks

The presented work aims at development of a management evaluation system (condition monitoring) in the event of an explosion using a network of wireless sensors. The flow of information in the situation assessment system is made possible with the applied energy autonomous and energy-efficient wireless sensor nodes. Through this evaluation system, we will be able to do a real time assessment on the state of the damaged infrastructure through which we will be able to react to the situation in the area in a timely manner. We will show a new wireless sensor network topology and develop new rules for self-synchronization for energy efficient and collision free communication which is capable of data transmission in the event of an emergency situation.

Results from German research project I-LOV

This paper presents the I-LOV system which is the result of a homonymous German integrated research project aiming at improving Urban Search And Rescue (USAR). It comprises three search technologies for the detection and localization of trapped or buried unconscious victims and auxiliary assisting technologies. Victims can be localized through their cellular phone (GSM) if it is active, but this state is not necessarily given. First results detecting inactive phones are presented. However, a victim may not have a phone. In this case, a ground-penetrating radar can be used. A continuous wave and an ultra-wideband (UWB) radar system are presented. A channel model for estimating signal disturbances in debris between victim and receiving antenna is proposed that aims at improving the accuracy of these technologies. Furthermore, the I-LOV system assists decision-makers by a digital communication infrastructure that allows gathering and by an IT-system called FRIEDAA that allows processing, and representation of relevant information such as search results and personnel locations. Therefore, infrastructure and inertial sensor based personal localization systems are presented.