Title page for ETD etd-02212005-184200

Type of Document Master's Thesis
Author Keaveny, John Joseph
Author's Email Address john.keaveny@gmail.com
URN etd-02212005-184200
Title Analysis and Implementation of a Novel Single Channel Direction Finding Algorithm on a Software Radio Platform
Degree Master of Science
Department Electrical and Computer Engineering
Advisory Committee
Advisor Name Title
Buehrer, Richard Michael Committee Chair
Reed, Jeffrey Hugh Committee Member
Tranter, William H. Committee Member
  • Pseudo-Doppler
  • Circular Antenna Array
  • Software-Defined Radio
  • Single Channel Direction Finding Systems
  • Watson-Watt
  • Adcock Antenna Array
Date of Defense 2005-02-11
Availability unrestricted
A radio direction finding (DF) system is an antenna array and a receiver arranged in a combination to determine the azimuth angle of a distant emitter. Basically, all DF systems derive the emitter location from an initial determination of the angle-of-arrival (AOA).

Radio direction finding techniques have classically been based on multiple-antenna systems employing multiple receivers. Classic techniques such as MUSIC [1][2] and ESPRIT use simultaneous phase information from each antenna to estimate the angle-of-arrival of the signal of interest. In many scenarios (e.g., hand-held systems), however, multiple receivers are impractical. Thus, single channel techniques are of interest, particularly in mobile scenarios. Although the amount of existing research for single channel DF is considerably less than for multi-channel direction finding, single channel direction finding techniques have been previously investigated.

Since many of the single channel direction finding techniques are older analog techniques and have been analyzed in previous work, we will investigate a new single channel direction finding technique that takes specific advantage of digital capabilities. Specifically, we propose a phase-based method that uses a bank of Phase-Locked Loops (PLLs) in combination with an eight-element circular array. Our method is similar to the Pseudo-Doppler method in that it samples antennas in a circular array using a commutative switch. In the proposed approach the sampled data is fed to a bank of PLLs which track the phase on each element. The parallel PLLs are implemented in software and their outputs are fed to a signal processing block that estimates the AOA.

This thesis presents the details of the new Phase-Locked Loop (PLL) algorithm and compares its performance to existing single channel DF techniques such as the Watson-Watt and the Pseudo-Doppler techniques. We also describe the implementation of the PLL algorithm on a DRS Signal Solutions, Incorporated (DRS-SS) WJ-8629A Software Definable Receiver with Sunrise ™ Technology and present measured performance results.

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