Bashir Ahmed Siddiqui

Joint Data-Pilot acquisition and tracking of Galileo E1 Open Service signal

Global Navigation Satellite Systems (GNSSs), such as the modernized Global Positioning System (GPS) and the ongoing European satellite navigation system Galileo, incorporate the new composite GNSS signals (e.g., Galileo E1 Open Service (OS) signal), which consist of two different components, the data and pilot channels. The existence of dual channel allows one to adopt special techniques to acquire and track these new signals. In this paper, the authors analyze the performance of three different implementation strategies, namely, i. Data-only, ii. Pilot-only, and iii. Joint Data-Pilot, for two different receiver modes: one with Sine Binary Offset Carrier (1,1) (SinBOC(1,1)) reference receiver, and the other one with Composite BOC (CBOC) reference receiver. All the simulations have been carried out in TUT Galileo E1 open source signal simulator, based on the most recent Galileo Signal-In-Space Interface Control Document (SIS-ICD). The simulation results show that acquisition with individual channel is not the best approach to acquire the signal as intuitively expected. Joint Data-Pilot channel combines all the significant power from data and pilot channels non-coherently that ultimately improves the signal detection around 2.8 dB, which has been verified via simulations in the context of the paper. Joint Data-Pilot channel also provides around 3 dB improvement over any individual channel in terms of tracking error variance. It will also be shown in the paper that the performance deterioration caused by using Sine BOC(1,1) reference receiver instead of CBOC reference receiver is negligible. Most of the findings based on data-pilot combination are as intuitively expected. However, the main novelty of the paper stays in presenting a realistic and detailed Simulink-based simulator for Galileo E1 signal that takes into account two receiver modes, and has already been made open access for research purpose.

Interference of touch dimmer lamps due to PLC and other high frequency signals

The interference of touch dimmer lamps due to PLC signals has found to be a common interference problem in Finland after the installation of smart meters that use PLC. One reason for this is the lack of equipment immunity standards for voltage frequencies below 150 kHz. This paper will study controlled discontinuous high frequency signal burst effect to two touch dimmer lamps in the laboratory environment. Both lamps were disturbed due to these signals. Based on the results it is possible that interference problems can occur even if the distance between lamp and the PLC device is close to 100 m. Paper will also show the measurement results on how one plug-in type filter improve interference situation. Results show that the amplitude of the signal burst will decrease at lamp side but filter also affects signal levels at mains side.

Experiences on narrowband powerline communication of automated meter reading systems in Finland

According to Finnish legislation, at least 80 % of the energy meters have to be remotely readable and provide hourly based energy data by the end of 2013. In April 2011 Tampere University of Technology (TUT) in co-operation with Finnish Energy Industry conducted a questionnaire to Finnish distribution network operators (DNOs) to map the installation status of the remotely readable meters, the communication technologies used in the meters and the interference problems experienced so far, related to, especially, PLC (power line communication) systems. The questionnaire dealt with both the interference caused by customer apparatus to PLC and vice versa. On-site measurements to study common customer apparatus disturbing the PLC were also conducted in 2012 in the networks of a few DNOs. Most common disturbance sources were frequency converters and switch mode power supplies. The measurements indicate that in addition to the lack of emission standards below 150 kHz the aging of customer equipment may be a relevant cause of interference problems.

Novel inductive sensor solutions for on-line partial discharge and power quality monitoring

Networks of medium voltage have spread over a long distance through underground cables. The aim to prolong the life span of existing network assets increases the need for condition monitoring to prevent unplanned and long lasting interruptions. Continuous on-line partial discharge (PD) measurement is an excellent way to determine the overall health of the medium voltage (MV) components and to detect developing faults in underground cables. A sensor is an essential part of the PD monitoring system which measures the high frequency PD signals. PD sensors can be used to measure power frequency current and harmonic currents on the MV side to estimate the thermal loading of transformer or incoming cable provided that the sensors have a suitable frequency response for measuring low frequency signals as well. A novel inductive sensor is described in this paper which allows both PD measurements as well as power quality (PQ) measurements at frequency range below 2.5 kHz. Authors did experiments on different ferrite cores in order to design the best possible sensor which can be used for both PD and PQ measurement. Characteristics of the sensors, including sensitivity, saturation current, and frequency bandwidth, as well as relative errors are provided and analyzed under laboratory conditions. At the end, developed sensors are compared with a commercial HFCT sensor, the Rogowski coil and power quality current sensors to show the capability of the sensors to be used for PD and PQ measurements.