Wireless Sensor Networks for Spacecraft DAMON PARSY, CEO OF BEANAIR R ETHINKING SENSING TECHNOLOGY
About Beanair (1/2) Designer and manufacturer of Wireless Sensor Networks Embedded measurement Process Industry Technical Building Management Environment 2
About Beanair (2/2) Based near PARIS (France) Company created in 2008 More than 15 employees Beanair products are designed and built in FRANCE Member of Astech (French Cluster in the field of aircraft and spacecraft) System integrator partners: USA, Europe, Australia, Brazil, South Africa and Russia 3
Beanair Wireless Sensor Networks
Requirements for Spacecraft applications Monitoring and controlling the behavior of a spacecraft, during testing phases on ground or during a space flight Short-range (10m to 30m) & low data-rate wireless sensor newtorks Hundred of measurement nodes are required, steadily increasing the mass (acquisition systems & cables) and the project costs and time Two different types of measurement modes: Static measurement (temperature, humidity) Dynamic measurement (acoustic, vibration) Fast response time Lossless data compression and transmission Time- synchronized and rugged wireless sensor network 5
Benefits: Easy to deploy and scalable Decreasing mass & wires Benefits & challenges of WSN Building new applications (HUMS - Health and usage monitoring system, moving parts) Challenges: Interferences (multi-path fading, radio jamming ) & obstacles Fast response time & time-synchronization Power supply & low power considerations 6
Let s build our wireless sensor network OSI Model Which wireless protocol? Application Transport Network Data Link Physical 7
Range 1000m 100m Ultra Narrow Band (UNB) Existing wireless protocols on the market IEEE 802.15.4 (Zigbee, WirelessHART, ISA100A ) IEEE 802.11/WIFI 10m 1m NFC/RFID IEEE 802.15.1 Bluetooth UWB /WirelessUSB 1K 10K 100K 1M 10M Data Rate (bps) 8
Why choosing IEEE 802.15.4 MAC Layer? Lightweight MAC Layer (10 to 20 Kbytes of flash memory instead of 4MBytes for the WIFI) Comes with a fast response, low data rate (typically: 250 kbps) & low power Provides a better wireless range than Bluetooth or Wifi But what about the existing standard wireless protocol based on the IEEE 802.15.4? Zigbee wireless protocol is more suitable on Energy Metering and Smartgrid markets but response time is not guaranteed WirelessHART and ISA100A are used on process industry market : Not easy to deploy and not compatible with dynamic measurement Mesh network is not needed on a spacecraft! 9
IEEE 802.15.4 Task Group IEEE 802.15.4 amendment Main features IEEE 802.15.4-E (2012) CSMA-CA Channel access Data rate: 250 kbps RF channels: 16 channels in the 2.4GHz IEEE 802.15.4-A (2007) Higher precision ranging ( 1 meter accuracy) CSMA-CA Channel access PHY is based on IR-UWB ( Impulse Radio Ultra wide Band) and CSS (Chirp Spread Spectrum) Data rate: up to 6.8 Mbps RF channel: 2.4 GHz (CSS), 3GHz to 8GHz (IR- UWB) IEEE 802.15.4-G (2012) CSMA-CA Channel access Data rates: 250 kbps, 40 kbps and 20 kbps RF channels: 16 channels in the 2.4 GHz ISM band, 10 channels in the 915 MHz, 1 channel in the 868MHz Process Industry Applications Real Time location systems (RTLS) Smart grid network (large network with millions of fixed endpoints) 10
Which amendment? IEEE 802.15.4G: Wavelength ~12 inchs (for frequencies 868 MHz to 915 MHz), same order as the size of many spacecraft cavities One frequency available in the 868 MHz : not compatible with frequency hopping; 900-915 MHz - not license-free for Europe, 868MHz not license-free for USA IEEE 802.15.4E: 2.4GHZ worldwide license-free Co-existence with Wifi and Bluetooth Wavelength ~5 inchs IEEE 802.15.4A: Wavelength ~1.4inchs to 5inchs Time-synchronization based on two way ranging Rake receiver counters the effect of multi-path fading Few IC providers on the market 11
MAC Layer: Medium Technique Access CSMA-CA (Carrier-sense multiple access with collision avoidance) Features Channel access is done at random time Bursty and aperiodic traffic flow Advantages Easier network management Well suited for ad-hoc network architecture Drawbacks QOS (quality of service) is not guaranteed Not deterministic GTS (Guaranteed Time slots) or TDMA (Time Division multiple access) Periodic traffic flow Better Quality of Service (QOS) Provides a deterministic network behavior Supports interference avoidance technique such as frequency hopping Crystal temperature-drift should be considered Complex 12
WSN Topology : Star Network WS WC WS WS WC: wireless coordinator WS: wireless sensor WS 13
Middleware layer: Benefits of 6LowPAN Open standard (defined by IETF) Lightweight software stack IPv6 over Low-Power Wireless Area Networks Low-overhead Multiple network topology options (Mesh, Cluster-tree, Star) Compatibility with TEDS sensor (IEEE 1451.5 specifications) Provides multicast routing (not available on the IEEE 802.15.4 MAC layer) TCP/IP Protocol stack TCP UDP ICMP IP Ethernet MAC Ethernet PHY OSI model HTTP RTP Application Application Transport Network Data Link Physical 6LoWPAN Protocol stack UDP ICMP IPV6 with LoWPAN IEEE802.15.4 MAC IEEE802.15.4 PHY 14
Multicast routing Request WC ACK+ Response WS ACK+ Response Request WS Request ACK+ Response WS WS 15
Building a «standard» wireless sensor for spacecraft Recipe of our «Grand Chef» Gusteau: IEEE 802.15.4-A/E Mac Layer CSMA/CA or GTS technique access Star network architecture 6LowPAN 16
Wireless Sensor Networks for spacecraft market (1/2) Beanair is working on an innovative wireless sensor networks dedicated to the new generation of spacecraft (Ariane VI) 17
Wireless Sensor Networks for spacecraft market (2/2) Telemetry sub-system gateway WSN based on IEEE 802.15.4 Wireless sensor Wireless coordinator IEEE 1588V2 protocol Wireless sensor Wireless sensor Wireless sensor 18
THANK YOU FOR YOUR ATTENTION Phone: +33 (0)1 83 62 16 38 info@beanair.com Visit us: www.beanair.com www.industrial-wsn.com 19