This thesis proposes a super-fast-scanning (SFS) technique as a viable fast scanning technique for phased array weather radar applications. The SFS technique can overcome the scanning speed limitations of the conventional scanning method of point-and-dwell, such that several times scanning speed improvement can be achieved.
Our motivation for researching this SFS technique is: (1) the ongoing need for a fast scanning technique in order to provide early warning of hazardous weather phenomena in airport terminal areas, and (2) the need to improve the scanning speed beyond that attainable with phased array radar using the conventional scanning method. In addition, research into an SFS technique has become possible due to recent advances in phased array technology that make instantaneous beam switching and multi-functional beam scanning possible.
The proposed SFS technique has never been studied, assessed,
analyzed or applied to the weather radar field. Our goal in this thesis is therefore to present the SFS technique, identify its features, diagnose its weaknesses, rectify its drawbacks, and verify the performances of its application to a phased array radar system by modeling with numerical radar system simulations.
It is shown that the scanning speed improvement by the SFS technique is limited by two major weaknesses: the first one is a reduction in the signal-to-noise ratio; and the second one is the additional sources of interference that we denoted the adjacent-beam-interference (ABI). To rectify these two weaknesses of the SFS technique, two auxiliary techniques are incorporated into a SFS implemented concept designed phased array radar (CDPAR) system that is designed specifically for microburst detection. These two auxiliary techniques are the pulse compression technique with Doppler tolerant sidelobe suppression filter and the noncomplementary
zero-cross-correction inner-outer code scheme. Theoretical analyses show that a maximal of 4 times scanning speed improvement can be achieved by this SFS implemented CDPAR system incorporating the two auxiliary techniques, when compared to the original CDPAR system using the conventional scanning method, if the weather phenomena detection accuracies of the two scanning systems are maintained.
Rigorous systematic validations are performed by numerical simulations of two scanning systems, a SFS implemented CDPAR system having 4 times scanning speed improvement and a CDPAR system using conventional scanning method. Extensive numerical simulations are used to compare the spectral moment estimate accuracy of both scanning systems detecting both a devised 2-dimensional wet microburst model and real observed thunderstorm weather radar data. The numerical simulation results show good spectral moment estimate accuracy in both scanning systems; hence validating the 4
times scanning speed improvement achieved by a SFS implemented CDPAR system incorporating the two auxihary techniques. We concluded that the SFS technique is a viable fast scanning technique for phased array weather radar applications. The significance of this research is that the successful application of the SFS technique to a modem phased array weather radar system can improve its scanning speed several times over that of the conventional scanning method. This fast scanning speed improvement is especially advantageous in microburst surveillance and detection situations. Further scanning speed improvement by the SFS technique can be achieved provided the two weaknesses can be reduced further.