Abstract
Measurement and characterization of ultra wideband (UWB) propagation and transmission within small spacecrafts were investigated with a view to (at least partly) displacing wired interface buses in spacecrafts with wireless links. Measurements were conducted in a mechanical test model of a small spacecraft and an equivalent shield box. The impact of apertures perforated on the outer surface and radio absorbers within the box were also examined. The following properties were derived there from: channel responses in the frequency- and time-domain, spatial distributions of UWB and narrowband propagation gains, delay spreads, and throughputs, the relation between delay spread and area of apertures and the absorber, and the relation between fading depth and the bandwidth. On the effects of apertures, the larger total area of apertures resulted in lower UWB propagation gains, shorter delay spreads, and slightly higher link throughput. Commercially off-the-shelf UWB devices were used in the experiments of UWB technology to facilitate a high data rate.
Highlights
The volume and weight of cables for connecting subsystems used for spacecrafts are increasing due to diversified onboard mission systems
The ultra wideband (UWB) propagation gains did not exhibit explicit dependence on distance, whereas the IEEE 802.15.3a channel model applicable to indoor environments used the path loss increasing with the square of distance
Without apertures: The spatial distributions of continuous wave (CW) and UWB propagation gains within the shield box are depicts in Figure 8, where no data exists in the vicinity of the origin [10]
Summary
The volume and weight of cables for connecting subsystems used for spacecrafts are increasing due to diversified onboard mission systems. Wireless technologies have not been utilized within spacecrafts as a physical layer of the interface. To realize these benefits, multipath propagation (namely reflected from the nearby walls) affecting the transmission performance must be scrutinized. Narrowband wireless links within a spacecraft were numerically calculated and experimentally evaluated in [2] [3]. We were considering the use of UWB for reliable connections inside the spacecrafts and experimentally evaluated UWB radio propagation in a small scientific spacecraft for replacing wired interface buses with wireless links [5] [10]. In this paper wideband and UWB propagation and transmission were measured in a mechanical test model (MTM) of a small spacecraft and an equivalent shield box.
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