Airborne passive SAR imaging based on DVB-T signals

Passive SAR imaging using DVB‐T illumination for airborne applications

“…Since many DVB‐T transmitters available in Europe broadcast more than one DVB‐T channel, higher range resolution can potentially be obtained. The key issue in this case, however, is that the DVB‐T channels are often located at different carrier frequencies resulting in gaps in the spectrum [13]. This, in turn, has an impact on the shape of the ambiguity function after range compression.…”

“…In the last few years, several airborne PSAR demonstrators have been developed showing the great potential of this technology [11–13]. One of the concerns regarding PSAR imaging is the trade‐off between image quality and computational complexity.…”

Passive SAR satellite (PASSAT) system: airborne demonstrator and first results

“…The preliminary investigation of the major system characteristics, such as resolution, sensitivity, satellite bus and payload have already been considered in [4]. Additionally, DVB-T SAR has already been shown to be fundamentally possible [5][6][7][8][9].…”

“…The second method is based on the assumption that the direct signal is inadvertently collected by the radar antenna itself (most likely through its side-lobes, but that depends on the bistatic geometry). Therefore, range compression can be implemented simply by auto-correlating the radar data [6][7][8]. This method relies on the direct signal having a sufficient Signal-to-Noise Ratio (SNR), however it eliminates the need for an extra receiving channel.…”

“…This is because if the direct signal is not decoded, but is instead used as is for range compression, a degradation in image quality may be expected as the SNR on the direct signal decreases. This is relevant to airborne DVB-T SAR since this can be used to understand how far away the receiver can be from the transmitter and still acquire useful imagery (see for example [5], [6][7][8], where transmitter-receiver baselines can vary from a little over 10km up to several 10s of km). It is also relevant to the space-borne PASSAT concept because as the receiver is on a satellite, not only its distance to the receiver can be larger, but also the direct signal is likely to be radiated through the sidelobes of the transmitting antenna.…”