I have been reading about "all-digital" or "software-defined radars". Lately, I was trying to simulate an FMCW short range radar in Matlab. One thing that struck me during the simulation is that to achieve a range resolution of around a 100 cm or less, the signal bandwidth is quite large -- in multiple GHz. This means, if one wishes to realise a digital implementation, one needs a really high speed ADC - multiple GigaSamples/second. Such ADCs are either not available and if you find something towards the top end of the high speed ADCs out there, the processing requirements are going to be ridiculously high. And of course, if you are clocking your baseband processor in GigaHertz, the power requirements of the device (typically an FPGA) are again going to be impractical.
How, if at all, high-resolution, high-bandwidth digital radars are realised in practice?
what would make sense in case of FMCW radar is to mix the transmitted signal and the target return signal and digitize only the beat frequency for Inverse FFT and further analysis. In that case, could you still call it a digital or software defined radar?