Master Thesis Research (2003-2004):
Design, Realization and Performace Evaluation of Ground Station System for Digital Radiosonde
Keyword : digital radiosonde digital, ground station, frequency tracking
Ground station developed for Digital Radiosonde application is designed to meet World Meteorological Organization (WMO) specification, i.e. coverage up to 150 km radii and packet loss rate 0.1. Assumed radio channel without shadowing, Rice distributed multipath with dominant non-fading component (K=10 dB), and flat fading. Based on the calculation, required receiver system sensitivity is -107.6 dBm.
System design involves 6-sector switched beams receiver antenna system, FM-FSK radio with frequency tracking ability, microcontroller-based user interface, and computer software. Data communication protocol on radio channel also designed using 9x packet repetition to get 4.0 dB gain compared to non-repetitive scheme. This research is completed in four phases: ground station system design, system element realization, integration and performance measurement. Realization results system sensitivity at -104,0 dBm based on laboratory measurement, and estimated more than 150 km coverage radii at 99% system availability.
Undergraduate Final Project (2002):
Design and Realization of 403 MHz FSK Receiver
Downlink communication of a telemetry system using FSK modulation scheme to convey digital information through air interface. FSK receiver in ground station is realized by modification of Evaluation Board RF2917, made by RF Micro Devices, as an FM/FSK receiver. Principally, the circuit is modified to change working frequency from 433 MHz to 403 MHz, considering frequency allocation for the telemetry. The receiver performance is then measured to determine its performance.