crockettjohnson rs presentation · crockettjohnson_ rs_presentation.pptx author: david sandwell...
TRANSCRIPT
Coral Bleaching and Satellite Remote Sensing
Economic Value
• Coral reefs hold $10 trillion in value and contribute $30 billion to global GPD annually
• Tourism and RecreaCon: $9.6 billion • Fisheries: $5.7 billion • Coastal ProtecCon: $9.0 billion • Biodiversity: $5.6 billion • Developing communiCes depend on reefs for sustenance and survival
Coral Bleaching • Rising ocean temperatures,
increasing ocean acidity, and polluCon all impact coral health
• Corals expel symbioCc algae when under environmental stress
• Coral bleaching can cause enCre reef ecosystems to collapse
• Cost to global economy: $20 billion to $84 billion
Satellite Remote Sensing and Coral Bleaching • Successes in mapping reef systems and monitoring ocean condiCons
• NOAA Coral Reef Watch
Mystery Satellite
• 60cm x 60cm x 80cm • Weighs less than 100kg • Achieves spaCal resoluCon of 80cm • 1.1 meter video resoluCon at 30 frames
per second • Costs less than $50 million • WorldView-‐3 weighs 2,800 kg and cost
$650 million • Two spacecraY currently in orbit • Revisit Time: 3-‐5 days
Mystery ConstellaCon
• Within a few years, firm will launch at least 12 more satellites
• All craY to follow same sun-‐synchronous orbit between 500-‐600km alCtude
• This constellaCon will achieve sub-‐daily revisit Cmes for every spot on Earth
• Unprecedented spaCal and temporal resoluCon
Image Processing • 35 cm aperture has naCve resoluCon of 1.4 m • Satellite captures mulCple images with an average exposure Cme around
400ms • “Super-‐resoluCon” algorithm determines homographies between
consecuCve frames • Stacking these frames averages out the noise and boosts the SNR. • All processing is ground based
Maneuverability
• These satellites feature a propulsion module • Frequent slewing will cause slight period variaCons for each satellite
• ConstellaCon spacing or “staConkeeping” • LEO Environment and Collision Avoidance
Scheduling
• EssenCal to avoid redundant imagery and decreased yield • w = overall weight • v = business value • a = number of previous imaging abempts • r= revisit potenCal • n = off-‐nadir angle • f = cloud-‐cover forecast
𝑤=𝑣(1−∑𝑎=1↑𝑁▒2↑−𝑎 )(1+ 4−𝑟/𝑟 )(1.2-‐0.013n)(1-‐0.5f)