GLADIS AIS Collection Performance Modeling

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GLADIS AIS Collection Performance Modeling

• TEXAS III
• August 2009

Co-Authors Jay W. Middour, Naval Research
Laboratory Dr. Lane Ellis, Naval Research
Laboratory
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Global Unclass/Non proprietary AIS Data Sharing
Denmark
Poland
Slovenia
Belgium
Montenegro
Bulgaria
UK
USA
Albania
Portugal
Turkey
Spain
Morocco
Italy
Mauritania
Greece
STP
Singapore
USN
Need more sharable dots !!!
50Countries to Date are sharing AIS data openly
via MSSIS.
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Small Maritime Vessels

• Vessels less than 300 Gross Tons
• Includes all types recreational boats,
  commercial fishing vessels, tugs, etc.
• Vessels with fewer security regulations
  information required by law, such as
• Automatic Identification System (AIS) requirement
• 96 Hour Advance Notice of Arrival
• 24 Hour Crew List
• Significant Challenge
• Relatively anonymous
• Free to navigate on the water
• Sheer volume and density
• 13 million privately owned pleasure craft
• 110,000 fishing vessels

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International Constellation
? Persistent wide-area surveillance ? Extracting
data from sensors in unwired regions ?
Leveraging industrygovernment partnerships ? 30
Nanosats ? ? Provide communications backbone for
global sensors ?
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Concept of Operations Overview

• Satellites collect AIS and Sensor messages from
  space
• Data protection is applied onboard satellite for
  downlink to nearest ground terminal
• Protected data stream is routed through the
  ground terminal to the Enterprise Server
• Capacity is shared based on Fractional Ownership.
  Information is shared via partner agreements

Border Sensor
AIS/ODTML Buoy
Fisheries Buoy
Environmental Data Buoy
Weather Buoy
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Satellite, Dispenser, and Ground Terminal

• Six Satellite Dispenser - Compatible with
  Minotaur I and Falcon 1

• Satellite Properties
• Mass 10-15 kg
• Size 30 cm cube
• Solar Power 21 W max
• UHF and VHF RF Payloads

• Inexpensive, portable UHF ground terminals

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Tilted Di-Pole Reduces Co-Channel Interference
(l/4 size each pole)
velocity
velocity
nadir
Ground Pattern
Tilted Di-Pole reduces instantaneous FOV by 1/2
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Co-Channel interference effect on message
demodulation

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Single Pass Analytical Solution

Mean Pass (min) 9.4
4.7 Expected Reports 94
47 per
Pass
Mean Pass (min) 9.4
4.7 Expected Reports 94
47 per
Pass
Mean Pass (min) 9.4
4.7 Expected Reports 94
47 per
Pass
Number of Ships
Single Pass in Antenna Pattern
Probability of Detection Traditional
Dipole GLADIS Traditional
Dipole GLADIS 500 250
100 100
1000 500 100
100 2000 1000
67 100 3000
1500 11
82 4000 2000
1 42
Number of Ships
Single Pass in Antenna Pattern
Probability of Detection Traditional
Dipole GLADIS Traditional
Dipole GLADIS 500 250
100 100
1000 500 100
100 2000 1000
67 100 3000
1500 11
82 4000 2000
1 42
Number of Ships
Single Pass in Antenna Pattern
Probability of Detection Traditional
Dipole GLADIS Traditional
Dipole GLADIS 500 250
100 100
1000 500 100
100 2000 1000
67 100 3000
1500 11
82 4000 2000
1 42
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GLADIS Performance is Estimated using HTS and
Analytic Co-Channel Model
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Tilted Di-pole Reduces Time to DetectionTime to
Detection (95 percent) in Minutes for 30
Satellite Constellation
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2
3
8
6
4
7
5
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Experimental Verification

• SpaceQuest Technical Services Contract with Naval
  Research Laboratory
• Collect SaudiSat AIS data using NRL Blossom Point
  Facility.
• Use the number of vessel-unique AIS message
  demodulated and the co-channel analytic model to
  calculate the number of ships present and compare
  to HTS

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New Messages Received Each Minute from Saudi Sat
Pass over Blossom Point
Satellite Sub-point
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The actual number of ships present may be inferred
SaudiSat Demodulation Results From 32 Snapshots
32 Footprint Population Estimates from Simulator
gt

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Comparison with HTS
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IMPORTANT POINTS

• Analytic Co-Channel Interference model is
  consistent with results from NRL / SpaceQuest
  Saudi-Sat Collection
• The method is used to predict co-channel
  interference for reduced field of view
• Tilted di-pole is an effective means of
  collection for small satellites like GLADIS
• Small Satellite Technology allows leap in
  capability/coverage at modest cost
• Engineering Development unit prototypes will
  undergo anechoic chamber tests in FY10

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• Additional Material

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High Level Statistics

• Average Rev Number of Unique Ships Seen 12,200
  ships 
• Maximum Rev Number Of Unique Ships Seen 19,000
  ships with EQX values of -30 and 140.
• Minimum Rv Number of Unique Ships Seen 5,500
  ships with EQX values of -100 and 70.
• HEre, a "Rev" is a collection from when the
  spacecrafT just cRosses the equator (which
  becomes the EQX) until the next equator crossing.
• Basically, the maximum collects move
  (north/south) through the center of the Atlantic
  and then (south/north) a little east of Japan.
• The minimum collects -ove (north/south) west of
  California and (soqth/north) across central
  Russia and India.

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