Date of Award

3-2006

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Electrical and Computer Engineering

First Advisor

Robert F. Mills, PhD

Abstract

Many current and emerging communication signals use Gaussian Minimum Shift Keyed (GMSK), Frequency-Hopped (FH) waveforms to reduce adjacent-channel interference while maintaining Low Probability of Intercept (LPI) characteristics. These waveforms appear in both military (Tactical Targeting Networking Technology, or TTNT) and civilian (Bluetooth) applications. This research develops wideband and channelized radiometer intercept receiver models to detect a GMSK-FH signal under a variety of conditions in a tactical communications environment. The signal of interest (SOI) and receivers have both fixed and variable parameters. Jamming is also introduced into the system to serve as an environmental parameter. These parameters are adjusted to examine the effects they have on the detectability of the SOI. The metric for detection performance is the distance the intercept receiver must be from the communication transmitter to meet a given set of intercept receiver performance criteria (e.g., PFA and PD). It is shown that the GMSK-FH waveform benefits from an increased hop rate, a reduced signal duration, and the introduction of jitter into the waveform. Narrowband jamming is also very detrimental to channelized receiver performance. The intercept receiver benefits from reducing the bandwidth of the channelized radiometer channels, although this requires precise "a priori" knowledge of the hop frequencies.

AFIT Designator

AFIT-GE-ENG-06-52

DTIC Accession Number

ADA447087

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