Preparation for Flight of Next Generation Space GNSS Receivers

Transcription

1 Changing the economics of space Preparation for Flight of Next Generation Space GNSS Receivers ICGPSRO, th May 2013 Taiwan # Commercial in Confidence 1

2 Overview SSTL and Spaceborne GNSS Small satellites for ocean sensing GNSS Reflectometry & UK-DMC WaveSentry project SGR-ReSI on TechDemoSat-1 NASA CYGNSS Mission Future of GNSS-Reflectometry 2

3 SSTL - the company UK-based satellite manufacturing company owned by EADS Astrium (99%) and the University of Surrey (1%) Formed in 1985, the Company now employs > 500 staff and occupies dedicated facilities in Surrey, Kent, Hampshire & Colorado Small Satellite manufacturer (approx 40 satellites built & launched) 3

4 Most Recent Mission: FS7/Cosmic-2 Taiwan/USA project Operational Meteorology GNSS Radio-Occultation SSTL provides satellite design 6+6 LEO platforms Launch planned 2016 and 2018 Contract Signature

5 Spaceborne GPS Receiver Examples PROBA-1 ESA technology demonstrator SGR-20 quad antenna receiver Still operational after > 11 years Strand kg Cubesat Carrying android mobile phone SGR-05U miniaturised receiver Launched February 2013 GIOVE-A ESA Galileo demonstrator SGR-GEO high altitude GPS receiver Positioning above GPS constellation November

6 Satellite Constellations and Sea State Single high-spec satellites have limited coverage E.g. Topex/Poseidon has 10 day repeat ground track Large gaps: limited value for dynamics and fine scale Satellite constellations give new opportunities High temporal, high spatial coverage feasible Validation of near real-time wind and wave models Long term observations for climate models Ice edge and concentration monitoring Towards operational monitoring service sea state, cyclones, storm surge, tsunamis, etc. To be feasible, need low cost, low power instruments, with adequate accuracy Target is for constellation to cost same as high-spec satellite 6

7 GNSS Reflectometry GNSS Reflectometry Detecting GPS / GNSS signals reflected off the Earth s surfaces Signals should contain geophysical imprint Using Earth-reflected GPS signals for ocean sensing first proposed in ESA proposed reflectometry for ocean altimetry PARIS ESA Oppscat study in late 90s 00s - scatterometry First reflected signal detected 1998 (JPL using SIR-C data) First dedicated in-orbit experiment: UK-DMC (2003) 7

8 UK-DMC-1 GPS Reflectometry Experiment Pioneering GPS Reflectometry experiment in orbit Carried on UK-DMC imaging satellite, launched Sept 2003 SSTL & BNSC Newton funding Hardware: GPS Receiver with IF output Data-recorder Medium gain 12 dbi LHCP nadir antenna Each collection 20 seconds of raw data To be processed on ground Imager Reflectometry Antenna First dedicated GNSS reflectometry experiment 8

9 Recovered Signals Processing sampled data reveals reflected signals Correlate data with GPS code & carrier Coherent 1 ms, then incoherent to 1 second Correlation shape related to ocean roughness (dmss) And dmss in turn related to wind speed ~60 collections gathered over sea, land and ice Signals collected from all surface types! 9

10 GNSS Reflectometry over ice January 2008

11 GNSS Land Reflections Nebraska, USA GPS PRN 18 11

12 WaveSentry Project 2012 Industry partnership to collate and exploit wave knowledge TSB (UK Govt) sponsored (50%) Led by HR Wallingford & MSE Data Suppliers: Buoys around UK Ferries / Ship wave instruments SSTL s GNSS-Reflectometry Other satellite wave data Potential Users: Off-shore wind and wave energy suppliers, Off-shore gas and oil, shipping management Scientists SSTL activities Reprocessing UK-DMC data using latest tools Found many more signals in data away from beam centre NOC converting data into dmss results and validating Preparing for launch of ReSI on TechDemoSat-1 12

13 Reprocessing UK-DMC Data Demonstration of open loop capability new signals available from old collections 42+ UK-DMC data acquisitions over ocean, with reflections from 114 PRNs (GPS satellite ID) However only some collocated with buoys, fewer with directional buoys. NOC working with retrieval algorithms Good convergence with mss Mixed results with direction determination Need for more data from future mission for validation! UK-DMC data R47 13

14 New Instrument Development CEOI Project: (UK Govt) 2009 / 2010 SSTL - Project lead, management, SGR-ReSI core development & test SSC - Antenna design and test National Oceanographic Centre (NOC) - Ocean Reflectometry applications & requirements, Inversion models & outreach Bath - Atmospheric applications & requirements Polar Imaging Ltd - Ice sensing Applications 14

15 SGR-ReSI Basic Block Diagram 4 x L1 antennas Dual Frequency antennas RF F/E L1 RF F/E L1 RF F/E L1/L2 RF F/E L1/L2 Program SRAM (1MB TMR) FLASH (16MB) GNSS Receiver Flash-based FPGA with LEON-3 Core interlink M Hz Co-processor SRAM-based FPGA (reprogrammable) Mass Data Storage DDR2 Interfaces: RS422 / LVDS / CAN / USB Power Supply LVDS (Hi rate Data) GNSS receiver core Enhanced GNSS instrument 16-40V 15

16 Delay Doppler Maps On-board Study supported by ESA Partnership with NOC, Southampton End-to-end instrument demonstration DDMs allow reduction of data rate x onboard => Towards continuous data collection 16

17 SGR-ReSI on TechDemoSat-1 TechDemoSat kg UK Satellite 8 UK Payloads Launch ~ Q ReSI config: Six front-ends Two dual frequency (L1 & L2C) antennas 5-10 watts, 1 kg Primary goals for ReSI Replacement for SGR-10 Ocean roughness sensing through reflectometry Collection of data for models Real-time demonstration Additional strategic goals Nadir Antenna 17

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19 CYGNSS Cyclones from GNSS CYGNSS for the Earth Venture-2 program CYGNSS measures ocean surface winds within tropical storms and hurricanes Aiming for better weather forecasting & assessment of hurricanes Partners include: University of Michigan - lead SWRI, NASA Ames, Surrey Satellite Technology-US LLC (SSTL subsidiary) Science team includes NOC presence Constellation of 8 microsatellites (18 kg) Payload is the SGR-ReSI Sensing GPS L1 signals reflected off seas under cyclones L-Band good choice penetrates clouds, rain in hurricanes Satellites to be operational in 2017 Prof Chris Ruf University of Michigan 19

20 Next Generation Receiver - SGR-Axio Derived from SGR-ReSI design (- minus Data recorder) Drop-in replacement for SGR-10 with extra capabilities Power ~ 4 watts, mass 1 kg Hardware support for: Dual frequency (L1 & L2C/L5) on up to 4 antennas Galileo, Glonass, Beidou (TBC) Precise Clock Module option (CSAC) testing planned First flight planned for 2015 Expect to use on all SSTL satellites and others Can support GNSS reflectometry if customer wants it Aiming to include GNSS Reflectometry on new DMC-class satellite mission kicking off in 2013 more satellites will follow 20

21 Conclusions GPS widely used on spacecraft for position & time LEO and beyond GNSS Reflectometry promising for ocean sensing UK-DMC experiment showed feasibility WaveSentry project has allowed reprocessing of data GNSS-R to be demonstrated on TechDemoSat-1 Launch planned Sept 2013 SGR-ReSI selected for NASA CYGNSS constellation 8 satellites for sensing hurricanes using GNSS-R SGR-ReSI / Axio as payload of opportunity Flying on SSTL s or other missions, low data rate streams Providing services for meteorology, marine users and scientists Broader applications for ice, snow, land sensing GNSS-Reflectometry on every satellite? 21

22 Changing the economics of space Thank You Presented by: James Nicholas Surrey Satellite Technology Ltd. Commercial in Confidence 22 Tycho House, 20 Stephenson Road, Surrey Research Park, Guildford, Surrey, GU27YE, United Kingdom Tel: +44(0) Fax:+44(0) Web: