Advanced Signal Analysis Techniques for Use on Non-Periodic Radio Frequency Signals

The objective of this Phase II effort is to develop and demonstrate wavelet-based digital communication signals for low probability of detection (LPD) applications. Novel wavelet-based signaling schemes will be compared to conventional digital communication waveforms in terms of bit error rate (BER) and probability of detection (Pd) as a function of signal-to-noise ratio (SNR) for fixed system parameters (e.g., bandwidth). The communication performance (BER) and LPD performance (Pd) will be predicted theoretically, and the theoretical predictions will be verified via Monte Carlo simulations. High-fidelity signal-level simulations of the physical layer of the corresponding digital communication systems will be performed for scenarios involving air-to-ground communication in maritime environments. The signal-level modeling & simulation (M&S) results will be used to develop digital transmitter and digital receiver software for use in real-world tests. Air-to-ground testing will involve a software-defined transmitter carried by a commercial aircraft equipped with an antenna pointing system capable of continuously pointing the transmit antenna at the ground-based receiver during flight. The ground-based software-defined receiver will be equipped with an Automatic Dependent Surveillance - Broadcast (ADS-B) tracking system capable of pointing the receive antenna at the aircraft during flight. Novel wavelet-based waveforms and conventional waveforms will be transmitted and received over a variety of conditions. The communication and LPD performance of all waveforms will be evaluated in post processing and compared to demonstrate the benefits of wavelet-based communication signals.