Cohort plc company Low Power Proximity Network of Sensors Eric W Pritchard Systems Engineering & Assessment Ltd CCSDS WWG Spring Meeting, May 2010

Cohort plc company LPPNS Wireless Project At Santorini we showed the LPPNS module used for RF wireless testing under ESA contract This has had propagation testing in a spacecraft model at Astrium Toulouse in nominal mode of operation, and in a launcher element mock-up at Les Mureaux in a high rate mode. Next stage for the LPPNS module is planetary demonstrator testing where we will be trying for maximum range and simulated nominal operation in a planetary context

Cohort plc company Summary of the LPPNS Tests One set of tests at Toulouse used a mock-up of a six cavity spacecraft based on the Venus Express spacecraft With the spacecraft walls closed the only RF pathways between cavities were holes a few centimetres across The tests showed positive link margin over the specification, which is conservative (receiver sensitivity of -85dBm, whereas commercial systems are achieving -100dBm or better) Good correlation with the Astrium model.

Cohort plc company Remaining Tests To complete the LPPNS work, there is the test in the launcher module to complete (two networks, data transfer continuous representing data acquisition in flight) The planetary demonstrator tests to do, testing maximum range, multipath effects and simulated operation in a representative environment

Cohort plc company LPPNS NG Demonstrators We have progressed from the LPPNS Modules tested in France to a smaller version predominantly aimed at temperature monitoring. This is still /Tiny OS based Presently we have the prototype boards ready to populate

Cohort plc company Module Assembly These boards have a flexible middle layer so can be folded, on the top is a chip antenna The module size is driven by high density population and battery size for a reasonable life This version has the ability to attach 2 thermistors or thermocouples to be positioned externally

Cohort plc company Cohort plc company Status of the CAN-BT Bridge This has been delivered and the SSC project has been successfully completed. Tests demonstrated that the Bluetooth system is compatible with operation as a bridge from a CAN bus on a spacecraft to a CANalyser on an EGSE bus. The project used the Bluetooth serial profile which may have other uses in spacecraft for data acquisition. Now some thought must be given to how to take this work forward.

Cohort plc company Cohort plc company Status of SpaceWire Bridge In a short test of compatibility, this has been connected to the MARC system and data has been successfully transferred from the MARC EGSE computer through the StarDundee USB- SpaceWire Interface to the MARC SpaceWire Cluster 1, through the backplane to the MARC SpaceWire Cluster 2, out to the SpaceWire EtherNet interface, over EtherNet to the n Access point, over n to the other Access point, then back to EtherNet to connect to the RF Wireless test PC.