Comparing phase-locked and non-phase-locked architectures for dual-channel DVB-S passive radar

This paper addresses the possibility to obtain low-cost passive radar that exploits DVB-S satellite transmissions as signals of opportunity using Commercial-Off The Shelf (COTS) hardware. In particular, low-noise down-conversion blocks (LNB) are typically available on the market, which include the Local Oscillator. Their use does not guarantee the fully coherent acquisition of surveillance and reference signal, required for passive radar operation. However, we estimate the frequency drift between the two channels, from the collected signals, and operate effectively for short-range surveillance applications. Using an ad-hoc experimental setup with 'less commercial' LNBs that can be locked to a reference, we compare two different types of receiver architectures: The non-phase-locked and a phase-locked architecture where the two LNBs are locked to the same 10 MHz oscillator. It is found that for small coherent integration times, the two schemes have very similar performance, whereas the phase-locked architecture is required to allow longer integration times and thus greater correlation gains. However, the lower-cost prototype is shown to be effective to detect and follow cars at least in the short ranges of typical parking-lots,