Photonic techniques for characterization and direction finding of wideband low-power waveforms
Abstract
Approved for Public ReleaseThis program aims to address the challenge of direction-finding (DF) of advanced radar waveforms with sho,rt-baseline arrays suitable for a variety of Naval platforms, including unmanned platforms where space is at a premium. We propose t,o explore photonic techniques, in particular radio frequency (RF) spectral interferometry and related schemes, for waveform DF and p,arameterization for electronic support (ES) applications.The basic approach of proposed effort is to artificially extend the baselin,e of a small array using a fiber optic delay line positioned after one of the array elements. Portions of the delayed and non-delaye,d signals are then combined to form an interference signal. The large static delay imparted by the delay line allows us to use proce,ssing techniques frequently used in the ultrafast optics and optical interferometry communities to extract phase information from mo,dulated interferograms. In contrast to direct cross-correlation which operates at nominally zero delay our technique processes corre,lation information well away from zero delay, thereby mitigating small path variations and correlated noise terms. Several architect,ures are envisioned ranging from a simple interferometer, to an interferometer designed to suppress common-mode noise terms, to anot,her designed to return both the direction of arrival, as well as waveform spectral phase information.Our objective is to demonstrate, 2-degree or better angular resolution using small-baseline (~1-m) arrays. We are targeting advanced threat waveforms (FMCW, phase-c,oded, etc.), with power levels at or below the noise floor (threshold of -10 dB signal-to-noise ratio integrated over the receiver b,andwidth). If this effort is successful, we will be able to provide a model for the angular accuracy of our technique, as well as de,sign parameters for small-baseline DF architectures based on operational parameters including waveform bandwidths and signal-to-nois,e ratio (SNR) of interest. This work could lead to improved detection of low-power threats in the littoral space and could enable DF, from compact platforms without space for large arrays, including unmanned aerial or surface vehicles.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 06, 2022
- Source ID
- N000142212839
Entities
People
- Jason D. McKinney
Organizations
- Office of Naval Research
- Purdue University
- United States Navy