Mustafa Emre Aydemir

Design and navigation control of an advanced level CANSAT

This paper presents design and navigation control of an advanced level comeback CanSat which is going to be launched to an altitude of about 400 m using an amateur rocket from ground level. The CanSat uses advanced and ultra-light microcontroller, pressure and temperature sensors, 3-axis accelerometer, 3-axis gyro, camera, GPS, IR distance measuring sensor, and RF communication module to communicate with the ground station PC. Three actuators are considered in this work for flight and ground segments control. They are the motor driven propeller, elevator and rudder. For the flight segment, parachute and attitude control are used to control the CanSat descent rate, attitude and heading. For the ground segment control; both the propeller and the rear landing gear of the CanSat is used for heading toward a predefined location on the ground. The rear landing gear is connected to the rudder rotational axis. An indigenous navigation control and electronic circuit design with the test results also are presented in this paper.

Design and implementation of a rover-back CANSAT

In this study, a CanSat with capability of returning back to target is designed amd implemented. The device is a part of project that has been implemented during the CLTP (CanSat Leadership Training Program) in Wakayama University. The CanSat is controlled by a state-of-the-art MBED 32-bit microcontroller. The main components are the pressure, ultrasonic, gps sensors and the 2.4 GHZ transmitter. The mission is planned for two stages which are flight back to the target by a paraglider and rovering on the ground on wheels. The process will be monitored on the ground station via the GoogleEarth software. The electronics&hardware design and the control algorithm is discussed in depth in this paper.

Ground station design procedures for CANSAT

CANSATs are getting more popular each day in aerospace engineering curriculums because they enable the students to have hands-on experience on virtual satellite launch operations. This paper presents design and implementation of a PC based ground station for CANSATs. So far, most of the emphasis has been built on the hardware and software inside the CANSAT. However, during the competitions it has been observed that even though the CANSAT works perfectly, the ground station frequently fails therefore leading to mission failure. In this study a ground station is developed from scratch using a high level language (C#) and the procedure is defined briefly. The station is platform-free therefore it may operate with any CANSAT having different brand microcontrollers. The users may track several parameters and send control commands simultaneously. The ground-station is one of the most important aspects of CANSAT trials however, for the beginners it may be challenging to provide all these features at once. This study defines many practical aspects of designing ground stations so that more emphasis may be given to the design of CANSAT hardware and software.

Application of Continuous Parameter Genetic Algorithm to the Problem of Synthesizing Bandpass Distributed Amplifiers

Summary Continuous parameter genetic algorithm (CPGA) is applied tosynthesis of monolithic GaAs FET bandpass distributed amplifiers for desired flat gain and maximum cutoff bandwidth. The results obtained by CPGA are compared with the results obtained by fuzzy genetic algorithm (FGA) and binary genetic algorithm (BGA).

Comparison of NEC simulation and measurement methods for the solution of coupling between airborne antennas

Many simulation methods have been developed for the solution of Electromagnetic problems. One of the best ways to evaluate the accuracy of these methods is comparing them with actual measurements. In this study, the optimization of the electromagnetic interference (EMI) induced by two aircraft on-board VHF-UHF transreceiver antennas is implemented. The EMI reduction is implemented by varying the antenna positions and orientations. The transreceiver antennas are modelled as single monopole antennas therefore the problem is reduced to antenna-to-antenna coupling optimization. The Method of Moments (MoM) is selected for the EMI analysis and the continuous parameter Genetic Algorithm (CPGA) is chosen for the optimization method. The results of the numerical analysis are verified by the measurement on a 1:10 scaled model in an anechoic chamber.

SAR image processing by a memetic algorithm

In this study, a recently invented evolutionary computing algorithm known as memetic algorithm is utilized for data processing of synthetic aperture radar (SAR) imagery. Since its invention by Dr. Holland in 1990s, Genetic Algorithm (GA) has already gained popularity in a wide range of engineering applications. The genetic approach is used for processing of SAR imagery to find a region of a pre-defined criterion. In this study, the Memetic algorithm is used for the search method. It was seen that, the algorithm is superior to deterministic methods in terms of processing times and finding the global minimum points. The proposed method is suitable to SAR image processing where huge amounts of data have to be processed in very short time intervals.

A novel approach for synthetic aperture radar image processing based on Genetic Algorithm

In this study, an evolutionary computing algorithm is utilized for data preparation and analysis of synthetic aperture radar (SAR) imagery for planetary geology. Since its invention by J.H. Holland in the 1990s, the Genetic Algorithm (GA) has already gained popularity in a wide range of engineering applications. The genetic approach is used for processing of SAR imagery to find a region of a pre-defined criterion. It was seen that the algorithm is superior to deterministic methods in terms of processing times and finding the global minimum points. The proposed method is suitable to SAR image processing where huge amounts of data have to be processed in very short time intervals.

The design and simulation of a compact Vivaldi Shaped Partially Dielectric Loaded (VS-PDL) TEM Horn antenna for UWB applications

Ultra wide band (UWB) antennas are of huge demand and Vivaldi antennas as well as the TEM Horn antennas are good candidates for UWB applications as they both have relatively simple geometry and high gain over a wide bandwidth. The aim of this study was to design such an antenna that achieves the maximum antenna gain over a bandwidth between 1 GHz to 10 GHz while minimizing the size of the antenna. The idea was to make use of combined respective advantages of Vivaldi antennas and TEM Horn antennas to achieve the desired goals by shaping the TEM Horn antenna to look like a Vivaldi antenna. The antenna structure was modified by partially dielectric loading it in the center to increase the gain and bandwidth. It was placed in a surrounding box made of PEC material to reduce the undesired side lobes to obtain a more directive radiation pattern. The simulations were performed by using the CST STUDIO SUITE Electromagnetic (EM) Simulation software. The results showed that the Vivaldi Shaped Partially Dielectric Loaded (VS-PDL) TEM horn antenna with 5 cm aperture depth had the best gain values over the desired bandwidth. This antenna is considered as compact enough for applications like hand-held impulsive Ground Penetrating Radar (GPR) and Electromagnetic Compatibility (EMC) measurement systems due to its reduced size and shielded metallic box structure.

Swarm intelligence in solution of impedance matching problem in Satellite Transmitters

This paper presents an ant colony optimization (ACO) method for the synthesis of impedance matching networks in Satellite Transmitters which is a demanding electronics engineering problem. The ACO method is a recent alternative for biologically inspired computing such as Genetic Algorithms (GA). In this study the ACO has been applied for the solution of impedance matching problem for the microwave transmission lines. The results are compared with that of the Continuous Parameter Genetic Algorithm (CPGA) method. The results are encouraging in terms of the quality of solution found, the average number of function evaluations and the processing time.

Design and Implementation of a Precision Accelerometer by Recursive Filtering for Spacecraft Instrumentation

This paper presents a simplified recursive filtering approach to noise removal process in modern accelerometers. The noise at the end of sensor output stems from the motion of the spacecraft during launch and orbital corrections plus thermal noise of the transistors. These two factors provide the ideal conditions for the application of the recursive filter where measurement and process noises are involved. The process noise covariance and measurement noise covariance matrices are the key variables of the filter. The resolution of the accelerometer is raised to a few mili Gs which provides the requested conditions for the application of autonomous spacecraft.