Networked radar systems: Waveforms, signal processing and retrievals for volume targets
by Bharadwaj, Nitin, Ph.D., COLORADO STATE UNIVERSITY, 2009, 174 pages; 3401022

Abstract:

Networked radar systems consisting of a dense set of agile short-range high frequency radars operating as Distributed Collaborative Adaptive System (DCAS) is an emerging innovative concept for atmospheric remote sensing that offer great potential to address several challenging problems in atmospheric remote sensing. This research addresses some of the unique challenges that must be overcome to successfully deploy a networked radar system. This research also provides a novel waveform and methodology for a networked radar environment and wideband waveforms for next generation precipitation radars.

The waveform design for a low-cost magnetron based dual polarization weather radar operating at X-band is presented. The waveform aims to concurrently address range-velocity ambiguity, ground clutter, hardware and operational requirements. Adaptive spectral processing of dual-polarization weather radar signals is presented for ground clutter suppression and range velocity ambiguity mitigation along with an evaluation of the spectral methodology based on simulations as well as data. The waveform and adaptive spectral processing is fully operational in the Integrated Project-1 (IP1) X-band radar network deployed by the Engineering Research Center (ERC) for Collaborative Adaptive Sensing of the Atmosphere (CASA). The IP1 radar network provides real-time data to the various end-users.

A transition from traditional high powered transmitters to solid-state transmitter is essential to realize a dense network of low cost electronically steered radars. However, solid-state radars have low peak powers and this necessitates the use of pulse compression waveforms. In this research a novel frequency diversity wideband waveform is proposed to mitigate low sensitivity of solid-state radars. In addition, the waveform mitigates the range eclipsing problem associated with long pulse compression waveforms. An analysis of the performance of this novel waveform is presented for volume targets.

In this research, two novel techniques using the concept of different look angles, inherent in a networked radar environment, is presented. The first technique is a networked waveform system where the range-velocity ambiguity problem is formulated for a networked radar environment by using the principle that the underlying intrinsic properties of the medium such as reflectivity and velocity must remain self consistent. A distributed waveform is designed to resolve the ambiguities of observations within the coverage region of the networked radar system. The second technique is a methodology for the enhancement of spatial resolution of reflectivity resulting from volume targets such as precipitation. The enhancement in resolution is obtained by jointly processing observations from the individual radar nodes. The resolution enhancement system (RES) uses the inherent nature of networked radar systems of observing a precipitation event with different look angles. Results and analysis for the networked radar algorithms are presented from simulations as well as data collected by the IP1 radar network.

 
AdviserChandrasekar Venkatachalam
SchoolCOLORADO STATE UNIVERSITY
SourceDAI/B 71-03, p. , Apr 2010
Source TypeDissertation
SubjectsElectrical engineering
Publication Number3401022
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