NovaSAR-S - Bringing Radar Capability to the Disaster Monitoring Constellation

Transcription

1 Changing the economics of space NovaSAR-S - Bringing Radar Capability to the Disaster Monitoring Constellation SSTL: Philip Davies, Phil Whittaker, Rachel Bird, Luis Gomes, Ben Stern, Prof Sir Martin Sweeting Astrium: Martin Cohen, David Hall USU Small Satellite Conference, August 2012, Logan, Utah

2 Contents Approach The NovaSAR-S solution Baseline capability First mission USU Smallsat

3 Changing the economics of space Approach

4 Traditional Approach Typical SAR mission requirements All things to all men Serving all applications means all imaging parameters optimised Swath, resolution, sensitivity, ambiguity ratio, duty cycle, imaging throughput.. Performance focused development Antenna size and power consumption driven to extremes Typical SAR mission budget required! >1000kg, >?00M. TerraSAR-X 1230kg COSMO-SkyMed 1900kg Radarsat kg USU Smallsat

5 Applications focused approach Starting point: What useful performance can we get from a minimal cost solution that fits low cost launches? Low mission cost target (spacecraft+launch+groundsegment) Follow optical Disaster Monitoring Constellation model COTS technology where suitable Medium resolution (i.e. not 1m) and wide coverage Constellation possibilities attractive BUT single platform must stand on its own merits SSTL optical satellites kg USU Smallsat

6 Maritime Services Target Applications Ship detection and tracking Oil spill detection and monitoring Iceberg detection and tracking Ice edge Monitoring Tropical Forest Monitoring De-forestation monitoring De-forestation prevention Disaster Monitoring Floods USU Smallsat

7 Changing the economics of space NovaSAR-S

8 NovaSAR-S USU Smallsat

9 NovaSAR-S Heritage avionics, bespoke structure S-band payload (Astrium) 400kg, 7yr lifetime, 24month lead time HH, HV, VH, VV polarisation options >2min imaging per orbit Payload antenna 3x1m Designed as a solution for medium resolution, existing applications where there is a market for more data or a desire for a national capability Packaging optimised rather than imaging performance USU Smallsat

10 Payload 18 phase centres: Transmit unit Receive unit Radiator unit Power conditioning unit Tx/Rx phase adjustment for beam shape and beam steering flexibility Frontend redundancy by graceful degradation Cold redundant dual payload backends S-band due to transmit units Commercially available GaN amplifiers Efficiency important for SAR payload >40% achieved Relatively mature technology at S-band USU Smallsat

11 Orbit flexibility Optimum altitude 580km Designed for multiple orbits: Sun synchronous polar orbit (LTAN 10.30) Equatorial orbit (15degree inclination) Minor mechanical changes - AOCS actuators Could be deployed in dawn/dusk orbit (LTAN 06.00) with additional NRE USU Smallsat

12 Development so far Satellite and payload design well advanced Astrium airborne trial collecting S-/X-band data Initial study by Surrey Space Centre Paper presented at APSAR 2011 Paper accepted for EUSAR 2012 Funding for PhD studentship secured Engaging with other academics Payload ground demonstrator 1/3 size antenna Inverse SAR test using ISS as target Early flight of front end technology on TechDemoSat-1 Q One phase centre of SAR payload used as an altimeter 50m Range Azimuth USU Smallsat

13 Airborne Results USU Smallsat

14 Airborne Results S-Band X-band Google Earth USU Smallsat

15 Airborne results, processed to simulate the results of the 6m resolution spaceborne system Airborne Results USU Smallsat

16 Changing the economics of space Baseline Capability

17 NovaSAR-S Baseline Imaging Modes Mode Incidence angles Res. Typical Swath Sensitivity (NEσ0) Ambiguity ratio * range only m 100km <-18dB <-16dB 4 No. of looks m 750km <-12dB <-18dB* N/A m 15-20km <-17.5dB <-16dB m 150km <-19dB <-16dB 4 Mode 1 20m resolution (like medium resolution optical imagers) plus max swath Typical mode for most target applications Mode 2 Maritime surveillance Mode 3 Trade swath for 6m resolution but maintain image quality Mode 4 Like mode 1 but trade resolution a bit for more swath Modes 1,2,4 scansar, mode 3 stripmap Baseline modes can be tuned in orbit by adjusting the pulse repetition frequency and beam steering USU Smallsat

18 Revisits Maximum and average revisit times in days: Mode SSO LTAN 10:30 Equatorial 15 Orbit 1 (20m) 2 (maritime) 3 (6m) 4 (30m) 1 sat 3 sats 1 sat 3 sats Av 4.4 Max14.0 Av0.9 Max8.0 Av3.2 Max12.5 Av 3.7 Max13.0 Av 1.5 Max3.5 Av0.3 Max0.5 Av1.1 Max3.5 Av 1.2 Max3.5 Av 1.3 Max6.2 Av0.5 Max0.9 Av0.9 Max2.2 Av 1.0 Max2.4 Av 0.4 Max1.0 Av0.2 Max0.8 Av0.3 Max0.9 Av 0.3 Max0.9 Where revisit means any opportunity using left/right imaging to image one location USU Smallsat

19 Throughput and duty cycle Assuming 2min (~2%) imaging per orbit: Mode 10 6 km 2 per day 1 (20m) (maritime) (6m) (30m) 1.8 Actual payload duty cycle dependent on orbit, mode, power, data storage, data downlinking, thermal considerations and groundstation number/location USU Smallsat

20 Changing the economics of space First NovaSAR mission

21 Status UK government grant announced in autumn budget statement to fund first satellite of NovaSAR constellation Other partners being sought by SSTL to complete the funding required to get to orbit 25% of capacity reserved 75% available Bulk data provision by SSTL/DMCii (raw, Level 1) Service provision by Astrium GEO Information Services KO May 2012 Flight readiness review April 2014 USU Smallsat

22 Ground segment TBC Northern/Equatorial Groundstation rented capacity SSTL S-/X-band Groundstation (Bordon) SSTL S-band Groundstation (Guildford) ISIC S-/X-band Groundstation (Chilbolton) ISIC S-band Groundstation (Harwell) Based on heritage SSTL systems Exact system TBC Nominal operations file transfer based and autonomous Service interface via Astrium Geo Information Services Payload tasking by DMCii/Astrium Housekeeping by SSTL Primary facilities possibly hosted by ISIC (EO Hub at Harwell, UK): Payload operations and data archiving Spacecraft operations Groundstation antennas SSTL/DMCii facilities used as backup ISIC KEY SSTL facility ISIC facility DMCii facility Other facility H/W S/W S/C operator (ISIC/SSTL) P/L operator (ISIC/DMCii) SRU CEMS AIC Rack PC Spacecraft Operation Centre (Guildford) Spacecraft Operation Centre (EO Hub Harwell) 4 x Windows PCs S-Band Chain S-Band Signal Generator CDM 600 (PSK modem) Data Switch/FSK Modem Router Upload Program (SW) SW Telemetry Display & processing SW File Handling SW / FTP Server Mission Operations Centre (Guildford) Mission Operations Centre (EO Hub Harwell) Mission Planning System (SW) NovaSAR MPS PC Antenna System (inc Amps & up/down Converters) Astrium P/L operator ARQ Msgs Automation System SW Orbital Elements (tle s) Raw, L1 and quicklook data Archive Users HMG, academia, industry X-Band Chain Demodulator Image Capture System (data buffer) Data Capture PC Images SW Decryption/ Decompression SW Image Handling Chain Image processor Astrium GEO Information Services Service development USU Smallsat

23 Secondary Payloads Small secondary payloads being considered Only minor mechanical changes to satellite possible Should not affect SAR performance, schedule etc. AIS currently SSTL preferred option Contemporaneous AIS/Radar Data USU Smallsat

24 NovaSAR-S Summary Low cost, medium resolution system Flexible modes of operation Launch 2014 of first satellite in constellation Investigating secondary AIS payload Looking for partners! USU Smallsat

25 Thank you USU Smallsat