Design of a receiver for measurement of real-time ionospheric reflection height

• Main Author: Raghavendar, Changalvala
• Format: Thesis
• Language: English
• Published: 2005
• Subjects: Fairbanks; Kodiak; Alaska
• Online Access: http://hdl.handle.net/11122/5999

Thesis (M.S.) University of Alaska Fairbanks, 2005 The HF (high frequency) radar at Kodiak Island, Alaska, is part of the SuperDARN (Super Dual Auroral Radar Network) network of radars designed to detect echoes from ionospheric field-aligned density irregularities. Normal azimuth scans of the radar begin on whole minute boundaries leading to 12 s downtime between each scan. The radar makes use of this down time, by stepping through eight different frequencies for each beam direction using 1 or 2 s integration periods. A new receiver system has been developed at Poker Flat Research Range (PFRR), to utilize the ground scatter returns from radar's sounding mode of operation and calculate the ionospheric virtual reflection height. This would result in considerable improvement in the accuracy of critical frequency and Angle Of Arrival (AOA) estimations made by the Kodiak SuperDARN. Introduction -- Background -- Structure of the ionosphere -- Photoionization -- Recombination -- Layers -- Ionospheric refraction -- Ionospheric propagation -- Reflection at vertical incidence -- Virtual height concept -- Oblique incidence -- Motivation -- Problem statement and proposed solution -- Equipment overview -- Basic radar definitions -- Overview of the HF radar at Kodiak -- Frequency operation -- Sounding mode -- Antennas -- Power -- Receiver antenna -- Reflector analysis -- GPS clock card -- Clock card specifications -- Overview of PCI card countrol/status registers -- The synchronized generator : GPS mode outline -- Software time capture -- Event time capture -- Receiver card -- specifications -- The system design and implementation -- Specifications -- The pulse sequence -- The QNX operating system -- Configuring the clock card -- Configuring the GC214 -- Sampling -- Mixing -- Decimation -- Filtering -- Resampling -- GC214 latency -- Gain -- Data header format -- Direct memory access (DMA) -- DMA buffer creation -- RAM--disk -- External trigger synchronization -- Signal processing code -- Link budget -- Results and future ...