Enhanced Active Imaging Through Fog
Abstract
Montana State University-Spectrum Lab investigates and develops innovative broadband coherent signal processing systems for defense applications. An RF modulated coherent lidar platform with range resolved digital holographic capability is currently being assembled, to enable 3D imaging of selected targets in fog environments. The requested instrumentation will significantly enhance the capabilities of the lidar imaging platform to achieve superior range selectivity, range resolution,image quality, and system robustness for field testing. The enhanced capabilities allow for the exploration of enhanced turbulence and vibration mitigation, while maintaining the high sensitivityand dynamic range needed for fog penetration and range discrimination.The proposed enhanced ultra-wide band lidar imaging system is well suited to EO/IRSensors and Sensor Processing operations. It offers improved cross-range image and longitudinal range resolution providing higher confidence in target location and identification, and better estimates of the velocity profile and vibrometric signatures of a target. Operations that benefit from high resolution ranging and imaging, particularly under fog conditions, include sea ship interdiction, ship docking, man overboard recovery, coastal transit security, and littoral navigation.Situational awareness is critical to naval operations, particularly in highly trafficked ocean, sea,and littoral environs where small ships and other objects can be obscured by fog.The funds requested under this DURIP will go to purchase several components andsubsystems. The funds will be utilized to: 1) Develop a Broadband photonic waveformgenerator capable of generating arbitrary waveforms, including linear frequency chirps and phase coded modulation waveforms, in the 17-34 GHz range. The wider bandwidth and ability to generate arbitrary waveforms will enable enhanced performance and adaptability for lidar imaging applications. The new design will also have reduced spurs and better out-of-band rejection, reducing false signals and enhancing signal detection and discrimination. Through the combination of advanced modulation formats with phase and polarization diversity, this platform allows for versatile waveforms to be tested and ultimately strategically employed to adapt to conditions and required modalities. Photonic waveforms with diverse modulation formats can be used to enhance range estimation and calibration through both optical heterodyne and correlative post-processingof received signals, as well as advanced sensing techniques; 2) Procure an Optical Modulation Analyzer to characterize and optimize the broadband photonic waveform generator for the production of high quality waveforms. Waveform characterization includes monitoring spectral band, modulation, power, efficiency and out of band rejection; 3) Procure a Long Coherence Length Optical Carrier to extend ranging capability from under a km to up to 10 km; 4) Develop a Rugged Broadband Optical Waveform Receiver and Digitizer, that offers enhanced range window (without loss of SNR) and IQ processing. The high bandwidth will also augment our plan for faster chirps (higher chirp rates) for reduced susceptibility to vibrations. The rugged back endprocessing system with built in GPU will enable real-time processing at field tests; 5) Procure a Broadband Intensity Modulated Waveform Receiver that enables direct detection of intensitymodulated waveforms with bandwidths up to 10 GHz.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 09, 2021
- Source ID
- N000142112640
Entities
People
- William Babbitt
Organizations
- Montana State University
- Office of Naval Research
- United States Navy