I. Introduction
In the framework of solid state maritime navigation radars, a cost-effective modular demonstrator operating at S-band has been designed based on available instruments and COTS components. The RF carrier is modulated by an arbitrarily coded sequence. Received echoes are filtered and sampled after base-band down-conversion by a phase-locked vector demodulator. A software radar signal processor is implemented to evaluate multiple signal processing algorithms. Simple digital signal processing techniques are shown to drastically improve the overall receiver performance. Especially in a zero-IF architecture, a notable processing gain can be achieved with minimal hardware and computational requirements.