A novel source localization approach suitable for urban environments is proposed. The reliability against noise and other practical issues are investigated via simulation. A fingerprint database of transmitter and receiver candidate locations is obtained using an efficient ray launching simulator developed in earlier work. Following a pre-described path, a UAV (unmanned aerial vehicle) equipped with a radio receiver is simulated to generate time series of observations such as signal strength and angle-of-arrival for all possible transmitter candidate locations. The localisation algorithm uses an approach based on the DFT (discrete Fourier transform) and dynamic time warping (DTW). Using the fingerprint database and the measured time-series the best matching transmitter location is found. The algorithm is found to be robust to significant measurement errors and also to signification deviations in the actual path flown by the UAV.

The performance of GPS (Global Positioning System) in densely built urban areas is greatly undermined due to multipath propagation. Many attempt alternative means for urban navigation, of which the `fingerprinting' method has drawn much attention recently. However, the labor of site surveys and a constantly changing environment prevents `fingerprinting' from being an efficient solution. Therefore, we propose a propagation model which is used to obtain location fingerprints with the aid of modern computers thanks to their growing processing power. At the heart of the technique is the use of a ray-launching model from which a database is generated containing propagation parameters such as received signal strength, time of arrival and angle of arrival as a function of source and receiver location. These are then mapped with physical locations using an artificial neural network. Besides, a sequence based tracking tool is proposed to assist navigation with minimal communication required between mobile device and database. This paper details the generation of a database for real world geometries read from OpenStreetMap and the development of a localisation algorithm.

In this paper, a novel simulation tool has been developed to examine the statistics of polarization dependent loss (PDL) using short fibre links in the first instance. Hardware emulator which has been previously developed [1] was used to generate measurement results with the same settings as the simulator. The results show that the simulator works reliably, so it can now be used to simulate the statistical results for more realistic long distance communications systems. The results also prove that the PDL variance reaches a minimum when each of the fibre lengths is approximately equal.

The localisation of interference sources in radio systems is a long standing problem. This topic has been recently seen considerable interest in the context of jammers used to deny GNSS (Global Navigation Satellite Systems) reception on the ground. Such jammers are used (illegally) as privacy protection devices or more seriously to defeat tracking systems in order to commit crime. The growing reliance on GNSS systems such as GPS (Global Positioning System) means that there is also potential for considerably more dire consequences. Critical infrastructure such as telecommunications and electrical power systems can often be reliant upon GNSS for timing. In this paper we present a novel approach to source localisation based on a technique of radio "fingerprinting". The key objective is to exploit knowledge of the radio propagation environment so as to determine the location of a radio source from as few measurements as possible. At the heart of the technique is the use of a ray-tracing model from which a database is generated containing propagation parameters such as received signal strength and angle of arrival as a function of source and receiver location. These are then used as constraints against which measured data can be inverted to yield the source location. This paper details the planned approach and progress made towards the development of a suitable ray-tracing method and discusses the generation of a database and inversion methods.

In this paper, a polarization dependent loss emulator is designed with computer-driven polarization controllers and single mode fibre. It proves that PDL obeys Maxwellian distribution when it is expressed in decibels. By positioning the polarization controllers at different places in the emulator link, it also proves that positions of PDL components have a significant effect on the statistics of PDL in a fixed length communication system. As the number of polarization components involved and the communication fibre length remain as constants, the longer the uninterrupted fibre is, the smaller the PDL mean value is produced.

The main concern of indoor wireless communication system users is having a non-stop high quality service. To achieve this, base stations must be properly located in the environment, based on knowledge of the channel characteristics. In this work, ray tracing software is used to generate the channel characteristics, primarily the path loss, in order to create a cost function for the optimisation process. The minimisation of this cost function then gives the optimal base stations' positions. In the literature, indoor environments are mainly considered to be static; however, it is known that the environments are subject to changes such as opening doors and windows and movement of people. For this reason, in this work, a sample environment was considered in different scenarios and it was proven that the optimal transmitter position is sensitive to changes in the environment. Future work will look at active control of the base station(s) in order to counter the effect of these dynamic changes.

The nonlinear frequency sweep in frequency-modulated continuous-wave radar systems is analyzed. The main lobe broadens with the fast Fourier transform in the presence of distortion, which makes it difficult to resolve closely spaced targets. A novel modified-adaptive-sampling method is presented. To demonstrate the validity of the presented technique, a computer simulation was conducted, and the results show a marked improvement in the shape of the spectrum and the range resolution.

A novel windowed FFT MUSIC (W-MUSIC) algorithm is presented in the context of using ground penetrating radar (GPR) to detect closely spaced targets under noisy conditions. It is seen to give a better indication of targets than stand-alone FFT and MUSIC algorithms. Distorted signals are analysed, and with the MUSIC algorithm the reported target positions suffer high degrees of error, with the FFT the main lobe broadens making it difficult to recognise closely spaced targets. The use of the Short-Time Frequency-Transform (STFT) algorithm is examined. A novel Short-Time MUSIC approach is presented, it can be used to obtain higher time-frequency resolution than STFT method.

When applied to ground penetrating radar (GPR), the multiple signal classification (MUSIC) algorithm is an important frequency estimation method as it can detect very closely spaced targets, particularly when one of the target responses is substantially lower than another. The MUSIC algorithm however must be seeded with the number of targets to find and will indicate that number of targets regardless of the number of targets actually present. In the presence of relatively low levels of noise the MUSIC algorithm is prone to reporting the position of false targets in preference to weaker genuine target responses. In this paper a superimposed MUSIC technique is proposed to suppress false targets. A novel windowed FFT MUSIC (W-MUSIC) algorithm is examined using a linear sweep frequency in noise. It is seen to give a clear indication of targets in the presence of modest noise that prevents MUSIC from working.

When applied to ground penetrating radar (GPR), the multiple signal classification (MUSIC) algorithm is an important frequency estimation method as it can detect very closely spaced targets, particularly when one of the target responses is substantially less than another. The MUSIC algorithm however must be seeded with the number of targets to find and will indicate that number of targets regardless of the number of targets actually present. In addition, there is no reliable indication of the magnitude of the responses of the targets. In the presence of relatively low levels of noise the MUSIC algorithm is prone to reporting the position of false target positions in preference to weaker genuine target responses. In this paper a superimposed MUSIC technique is proposed to suppress false targets. A novel windowed FFT MUSIC (W-MUSIC) algorithm is examined using a linear sweep frequency in noise, and it is seen to give a clear indication of targets. In the presence of distortion, FFT is seen to be a more robust approach than the MUSIC algorithm, the latter method becoming very prone to inaccuracy in the presence of distortion.

Ultra wideband technology (UWB) is an emerging technology that has proven to be quite suitable for short range applications. This paper is part of an ongoing research for using UWB technology for positioning team-sport players on a playing area. Simulation is conducted for a number of “players” who are carrying RFIDs transmitting signals with biométrie information data about each player to a number of receiving antennas positioned around the field. We investigate the performance of UWB wireless systems using a novel partially developed fading channel and a novel SIMO diversity combining scheme with respect to the transmission range of the UWB devices. The main goal is to determine the required transmission power in order to get an acceptable QoS over the covered area in which the players are being tracked. The results showed that, UWB system is an excellent choice for such short-range applications.

Ultra wideband technology (UWB) is an emerging technology that has proven to be quite suitable for short range applications. This paper is part of an ongoing research for using UWB technology for positioning and remote sensing biometric information for team-sport players on a pitch, Simulation is conducted for a number of ldquoplayersrdquo who are carrying RFIDs transmitting signals with biometric information data about each player to a number of receiving antennas positioned around the field. We investigate the effect of multiple access interference (MAI) on the performance of UWB wireless systems using a novel MISO diversity combining scheme. The main goal is to determine the number of interferers that the system can handle before producing an unacceptable quality of service (QoS). The results show that, due to UWB low power spectral density characteristics, the system can handle a relatively large number of interferers.

This chapter described the application of hierarchical techniques to the diagnosis of large-scale analogue and mixed-signal circuits. The impetus behind the development of these techniques has been the continuing growth in size and complexity of these circuits. Often the computation effort required to implement traditional approaches to circuit diagnosis grows exponentially with circuit complexity and the hierarchical approach attempts to mitigate this effort by grouping blocks of circuitry that can be dealt with as individual modules.

This paper considers a new location scheme for ultra wideband (UWB) positioning system. The newly adopted scheme combines the time difference of arrival (TDOA) and the angle of arrival (AOA) positioning techniques in order to enhance the accuracy of the positioning system compared to the classical technique (TDOA). The new technique is simulated in a sports tracking application in a football field. Results are compared with results from a similar system using classical TDOA technique in order to establish a proof-of-concept. Simulation shows that the new technique is actually giving better performance with an acceptably longer processing time. This technique has the promise of boosting positioning accuracy with a relatively low level of complexity.

MIMO channel sounder has been used to evaluate several transmission diversity schemes by simulating a distributed antenna system in an indoor environment. Using three fixed transmit antennas and one mobile receive antenna, three channel impulse responses (CIRs) have been measured simultaneously for many receiver locations throughout a hypothetical coverage area. Using the measured CIRs, three diversity schemes have been simulated: selective antenna diversity, multipath antenna diversity and co-phasing transmit antenna diversity. The performance of the diversity schemes are compared using two metrics: gross power and RMS delay spread. Co-phasing transmit diversity achieves the best diversity gain without increasing significantly the delay spread.

The paper deals with the signal analysis problem encountered with ground penetrating radar (GPR) applications that use the fast Fourier transform (FFT). A technique for improved signal analysis based on superimposing multiple FFT analyses from the same data is presented. Results from applying the technique are seen to reduce the side lobes with minimal increase in main lobe width.