Multi-Stage Complex Notch Filtering for Interference Detection and Mitigation to Improve the Acquisition Performance of GPS

Continuous Wave Interferences (CWIs) can degrade the accuracy of a Global Positioning System (GPS) receiver and moreover it can completely deteriorate receiver’s normal operation. In this paper a low-cost anti-jamming system design is presented for the mitigation and detection of CWIs for GPS receivers. The anti-jamming system comprises of parameterizable Complex Adaptive Notch Filter (CANF) module which is able to detect and excise single or multiple CWIs. The CANF module is composed of a first, second and third order infinite-impulse response filter with an Auto-Regressive Moving Averager structure. The proposed CANF detects the existence of the CWI and estimates JNR level of incoming signal by using the statistical value of the adaptive parameter b0. The impact of the CANF module on the acquisition is analyzed. Moreover, a simple and innovative system level model is proposed which can utilize each CANF efficiently with threshold setting of JNR estimation within the adaptation block. Threshold setting parameters provide trade-off between effective excision of CWI, order of the filter and power consumption. This results in a parameterizable CANF module and provide effective solution for the mitigation of interferences with a high-power profile for GPS based applications

Hardware implementation of Modified Annular Ring Ratio for Blood Cell Detection in Thin Blood Smear Images

Malaria continues to spread in endemic areas. This deadly disease is the subject of multiple researches in terms of patient diagnoses. Post treatment diagnoses are necessary to make sure that patients treated for malaria continue to be free from Plasmodium protozoan parasites. Fast and automated analyses are possible with image processing of blood cell samples. This paper proposes a modified version of an image processing algorithm named Annular Ring Ratio, which identifies and locates the blood cell present in the thin blood smear images, to make the algorithm amenable to efficient hardware implementation through the elimination of the costly division process. The Annular Ring Ratio process identifies circular shapes through the calculation of a ratio between two circular areas. With proper configuration it can detect cell and parasite positions leading to the identification of infected cells and further estimate the level of infections

Tracking and Mitigation of Chirp-Type Interference in GPS Receivers Using Adaptive Notch Filters

A Global Positioning System (GPS) receiver is extremely prone to intentional and unintentional interference due to weak signal power experienced on the surface of the earth, which severely affects the navigation functionality and occasionally avoids the receivers from acquiring the GPS signal. This work presents a comparative performance analysis of two different types of Adaptive Notch Filtering (ANF) algorithms for GPS specific applications that are (1) Direct form 2nd Order ANF and (2) Lattice-based ANF for tracking and mitigation of Chirp-type Interference. Three classes of chirp-type interference signals, studied in this paper, are linear chirp, quadratic chirp and cubic chirp. Performance of each ANF algorithm is evaluated at the output of the acquisition module in terms of search-grid SNR and Peak metric

A Novel Optimization Algorithm for Notch Bandwidth in Lattice Based Adaptive Filter for the Tracking of Interference in GPS

The weak signal levels experienced at the reception of the messages transmitted by navigation satellites, makes Global Positioning System (GPS) vulnerable to unintentional and intentional interference. This calls for appropriate modelling of GPS signal sources and jammers to assess the anti-jamming and interference mitigation capabilities of algorithms developed to be implemented for GPS receivers. Using a practical simulation model, this work presents an anti-jamming technique based on a novel algorithm. A fully adaptive lattice based notch filter is presented that provides better performance when compared to existing adaptive notch filter based techniques, chosen from the literature, in terms of convergence speed whilst delivering superior performance in the excision of the interference signal. To justify the superiority of the proposed technique, the noise and interference signal power is varied for in a wide dynamic range assessing jamming-to-noise density versus effective carrier-to-noise density performance at the output of the correlator

A Fully Adaptive Lattice-based Notch Filter for Mitigation of Interference in GPS

Intentional interference presents a major threat to the operation of the Global Navigation Satellite Systems. Adaptive notch filtering provides an excellent countermeasure and deterrence against narrowband interference. This paper presents a comparative performance analysis of two adaptive notch filtering algorithms for GPS specific applications which are based on Direct form Second Order and Lattice-Based notch filter structures. Performance of each algorithm is evaluated considering the ratio of jamming to noise density against the effective signal to noise ratio at the output of the correlator. A fully adaptive lattice notch filter is proposed, which is able to simultaneously adapt its coefficients to alter the notch frequency along with the bandwidth of the notch filter. The filter demonstrated a superior tracking performance and convergence rate in comparison to an existing algorithm taken from the literature. Moreover, this paper describes the complete GPS modelling platform implemented in Simulink too

Magnetic & Spectral Properties of Oxovanadium(IV) Complexes withTridentate Dibasic ONO Donor Schiff Bases Derived from Isopropanolamine & Substituted Salicylaldehydes

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A Wireless Sensor Network for Early Forest Fire Detection and Monitoring as a Decision Factor in the Context of a Complex Integrated Emergency Response System

Wildfires, often dubbed megafires, have in recent times increased in both frequency and scale, owing largely to human error as well as climate change. Due to their uncontrolled unpredictable rapid growth and behaviour, they can quickly become difficult to contain, leading to significant loss of lives, wildlife and property. It is therefore critical to tackle such fires in the early stages. This demands a reduction in the initial time to detection while ensuring reliability and a low false alarm rate. This paper discusses a new category of compact, easily deployable and energy efficient approach to sensor nodes for the continued monitoring of forest environments as well as the early detection of fires in their infancy based on a combination of sensory inputs. The sensor network reported in this paper was tested with other subsystems/technologies, in a real-life firefighting trial as part of a coordinated firefighting scenario with promising results

Stress Analysis of Multi Leaf Spring by Using Experimental Method

Leaf springs are used in vehicles for suspension purpose in all type of vehicles. Ample amount of work has been done on the analysis of leaf spring. Researcher focused on the  analysis of stresses developed in spring by using different FEM tool also several worked on predict fatigue life of leaf spring. After review of available literature on leaf spring it is found that the very few literature is available on analysis of springs used for light commercial vehicle. This paper describes the static analysis of multi leaf spring by using experimental method i.e. strain gauge under various loading conditio

Conversion of Natural Resources through Waste reduction at the Processing Step by Briquetting Technique

India is gifted by nature by way of large quantities of high grade nonferrous mineral resources like barite containing more than 90% barium sulphate. The processing of barite to win chemicals from it requires its carbotherrnic reduction at high temperatures being carried out in rotary furnaces. The powdered charge containing barium sulfide is prone to get damaged due to reverse reaction caused by infiltered oxygen at the end of reduction state. This hampers the yield of water soluble barium sulfide.The paper discusses about the means of achieving favourbale kinetics and high recovery of water soluble barium sulphide in the carbothermic reduction of barite at high temperatures. The reaction rate of reduction step was enhanced many folds by using briquetting technique. Even with barite containing large amnount of harmful impurites, the yield of barium was improved considerably on pilot plant scale, thus achieving better utilisation of natural resoures such as barite and coke

James van Allen and his namesake NASA mission

Abstract In many ways, James A. Van Allen defined and “invented” modern space research. His example showed the way for government-university partners to pursue basic research that also served important national and international goals. He was a tireless advocate for space exploration and for the role of space science in the spectrum of national priorities