Investigating the use of hopped frequency waveforms for range and velocity measurements of radar targets

Includes bibliographical references.In the field of radar, High Range Resolution (HRR) profiles are often used to improve tracking accuracy in range and to allow the radar system to produce an image of an object. This work focuses on the use of HRR profiles generated using a sub-class of HRR techniques termed hopped frequency and stepped frequency waveforms. These wideband waveforms are usually synthesised by combining the spectra of the transmitted pulses in the burst [1]. When used with hopped frequency waveforms, this adds the advantage of range-Doppler decoupling and robustness against electronic countermeasures (ECM) [2, 3]. However these waveforms suffer from high levels of sidelobes [4] and improving the spurious free dynamic range (SFDR) of target measurements was required. This was done with the CLEAN technique [5] which could reduce sidelobe levels to below -60 dB and would allow smaller targets masked by the sidelobes to be uncovered. To analyse the practicality of this work, simulated rotating scatterers were used and these techniques could perform adequately for signal to noise ratios (SNR) above -10 dB and signal to clutter ratios (SCR) above 14 dB. Clutter mitigation is to be investigated in future work to make it applicable to lower SCR and sub-clutter visibility