UWB radio channel characterization and design for intra spacecraft communication

ESA is investigating wireless cable replacement for intra-spacecraft (IS) applications to reduce cable weight, and add flexibility to the subsystem layout. The low emission limit and robustness to highly reflective environments make UWB a potential candidate for cable replacement. Therefore, to validate these assumptions, channel measurements have been conducted in a representative spacecraft; the ESA Venus Express mock-up, which is divided in separate compartments/cavities connected by openings. Channel measurements that cover the entire 3 to 10 GHz UWB spectrum, are conducted for all cavity combinations of the Venus Express. Channel statistics are derived from the measurements. Moreover, the raw channel measurements are used in a hardware-true physical layer (PHY) simulator, based on current Holst Centre - IMEC UWB hardware platform supporting IEEE 802.15.4a standard. The used hardware specification are from the non-coherent setting, employing power detection and integrate and dump in RX for easy synchronization in a highly reflective environment, insensitivity to clock jitter, and robustness against clock offsets at cost of reduced sensitivity. The PHY results correspond well to the outage probability derived from the channel measurements when taking the actual noncoherent setting receiver hardware sensitivity into account. Since most power is in the scattered power, the most dominating factor in IS UWB communication is not the actual position or distance between the antennas, but the minimum number of openings between the cavities. The low mean loss of the measured radio channel combined with the immunity of the UWB air-interface to small-scale-fading, ensures that the signal is always well above the noise floor of the non-coherent setting of the current Holst Centre - IMEC hardware.