Martin Drobczyk

A study on low-latency wireless sensing in time-critical satellite applications

The utilization of wireless sensor networks in satellite applications is promising, but at the same time a challenging task due to the stringent requirements. Especially time-critical subsystems, like the attitude and orbit control system (AOCS), require a low-latency and robust communication within its sensors and actuators network. In this paper, we propose a novel approach for wireless intra-satellite communication, which is based on the recently introduced IEEE 802.15.4e with its low-latency deterministic network (LLDN) mode utilizing IEEE 802.15.4a impulse radio - ultra wideband (IR-UWB). The analysis shows that it is able to fulfil the strict timing requirements in order to accomplish a deterministic communication with a latency of 10 ms and less in a typical AOCS configuration.

A Wireless Communication and Positioning Experiment for the ISS Based on IR-UWB

This paper introduces a wireless experiment for sensing and positioning to be deployed in the Columbus module of the International Space Station (ISS). The experiment allows the monitoring of environmental parameters and it demonstrates the motion tracking of astronauts or free-flying objects by utilizing impulse radio - ultra wideband (IR-UWB) in combination with Micro Electromechanical Systems (MEMS) sensors. Recent work revealed a great potential in utilizing WSN in space habitats; however, the focus was only based on sensing in the narrowband Industrial Scientific and Medical (ISM) 2.45 GHz band, whereas this work extends these capabilities by utilizing IR-UWB for positioning and it optionally uses internal light sources for energy harvesting to drive the sensor nodes. The paper describes the operational scenario and the hardware and software concept are presented in detail. Finally the expected results are presented, which focus on the analysis of different use cases for the implementation of wireless sensor networks and to help and to identify new applications for future space missions.

Deployment of a wireless sensor network in assembly, integration and test activities

This paper evaluates the deployment of a wireless sensor network (WSN) to support and speed-up the assembly, integration and test activities in a satellite project. We focus on the thermal vacuum tests, which come along with an extensive amount of sensors to monitor the thermal behavior of the spacecraft. Recent work revealed a great potential; however, the focus was on passive technologies based on radio frequency identification (RFID), whereas this paper evaluates the deployment of a low-power active WSN based on the recently introduced IEEE 802.15.4e-2012 standard. Possible obstacles are examined and tests in a thermal vacuum chamber are performed to analyze the sensing capability in detail. Finally the results are presented, which demonstrate the functionality with a nearly error-free communication performance.

Antenna subsystem far-field characterization of the spin-stabilized satellite Eu:CROPIS

In this paper, we present the far-field characterization of the antenna subsystem of the Eu:CROPIS (Euglena and Combined Regenerative Organic-Food Production in Space) satellite. Its specialty, in contrast to other satellite missions, is the spin-stabilization used in order to simulate the Moon and Mars gravitational fields for the biological on-board experimentation. Thereby, spin rates of up to 30 rpm are obtained, which have influence on the communication link. From the perspective of the ground station, the far-field becomes dynamical, including phase rotations and amplitude variations. Both can degrade the communication link and might lead to a loss of signal. Hence, a detailed analysis of these destructive phenomena is essential to be able to test possible effects on the receiver electronics beforehand and to avoid such issues in orbit. The far-field characterization is therefore an essential part of the overall design and verification process. It is initially performed by an Electromagnetic (EM)-field simulation, utilizing a (Multi-Level Fast Multipole Method) MLFMM-solver. After the identification of critical regions a mock-up based measurement in an anechoic chamber is performed to verify the simulated results. This paper introduces both characterization methods and compares the results.

EMC characterization of the UWB-based wireless positioning and communication experiment (wireless Compose) for the ISS

This paper presents the results of an electromagnetic compatibility measurement campaign, which was performed for a wireless experiment for sensing and positioning (wireless Compose) to be deployed in the Columbus module of the International Space Station (ISS). The experiment allows the monitoring of environmental parameters and it demonstrates the motion tracking of astronauts or free-flying objects by utilizing impulse radio — ultra wideband (IR-UWB) in combination with Micro Electromechanical Systems (MEMS) sensors. Recent work revealed a great potential in utilizing wireless sensor networks (WSN) in space habitats; however, wireless systems can interfere with already existing and almost sensitive on-board systems. Therefore, a detailed analysis of the electromagnetic characteristics is mandatory to avoid any incompatibilities with the ISS equipment. The paper introduces the tested hardware and describes the measurement flow in detail. Finally, the results are presented, which focus on the radiated emissions and radiated susceptibility.