1. Robert Erlandson, M. A. Kelly, C.A. Hibbitts, J. Boldt and K. Sotzen
JHU Applied Physics Laboratory
Capt Andrew Tran
Air Force Space and Missiles Center / WM
Compact Terrestrial Weather
Sensing for Small Satellites
and Hosted Payload
12 August 2013

2. Theater
weather
imagery
constructed
from
EO/IR
0.65-­‐,
0.90-­‐,
and
10.8-­‐μm
channels
(hEp://cimss.ssec.wisc.edu/goes/blog/
poesavhrr-­‐in-­‐awips)
Challenge
§ DMSP
Satellites
reach
end
of
life
around
2020.
The
Air
Force
SMC
seeks
affordable
space-­‐based
terrestrial
weather
soluUons
to
meet
DoD
weather
requirements
Desired
Sensor
A1ributes
§ Capable
§ Cost
EffecUve
§ Compact
MSIS
Field
of
View
2
Theater Weather Imaging

3. METOC Requirements
JROCM
91-­‐012
Lists
Top
Two
Capability
Gaps
noted
by
arrows
3

4. Multi-Spectral Imaging System
Bands
Camera Wave-Bands Requirement
VNIR 500-900 nm Low Light Imaging (Night)
VNIR 400-430 nm TW Imagery, Cloud, Aerosol, Smoke, Dust
VNIR 605-685 nm TW Imagery, Cloud, Snow, Aerosol, Vegetation
VNIR 845-885 nm Cloud, Vegetation
SWIR 1.58-1.64 µm Cloud, Aerosol, Snow
LWIR-1 8.3-8.8 µm Cloud, Ash, Fog/Stratus, Multi-layer Cloud
LWIR-2 10.8-11.3 µm TW Imagery, Cloud, Snow, SST, LST, Multi-layer Cloud
LWIR-3 11.8-12.3 µm Imagery, Cloud, Snow, SST, LST, Fog/Stratus
4

5. Multi-Spectral Imaging Sensor
Uncooled LWIR Sensors Summary
Compact and Cost Effective
Leverages uncooled COTS camera technology to
provide an affordable EO/IR weather sensor
Modified COTS Camera
- Digital Time Delayed Integration to Increase SNR
- Space Qualified Electronics
- Radiation Testing
Benefits
- No Active Cooling Required
- Small Form Factor
- Sensitivity for Weather Applications
LWIR
Uncooled
Micro-­‐Bolometer

6. 6
Multi-Spectral Imaging System
Uncooled LWIR Sensor Specifications
LWIR Sensor Summary
Cameras 3
Filter Bands 8.4µm,10.8µm,12µm
Pixel Dimensions 17 µm
Array Size 1024 x 768
FOV 40° x 40°
Spatial Resolution 760m (nadir)
• Detector:
1024
x
768
pixels
• Uncooled
Microbolometer
Array
• CharacterizaUon
of
Camera
in
Progress
• Conducted
radiaUon
tests
of
the
sensor,
concluding
that
the
detector
can
withstand
a
total
dose
of
20
krads.

7. 7
q Employs separate optics and detectors for each waveband.
q Supports Straight Forward Technology Insertion
q Size:
• 16 x 4 x 4 inches
• Weight: 10 kg
MSIS – Sensor Packaging
Band
Center
λ
(um)
FWHM
(um)
Vis
.412
.03
VIS
.645
.08
NIR
.865
.04
SWIR
1.610
.06
LWIR
8.4
0.8
LWIR
10.8
1.0
LWIR
12.0
1.0
Low
Light
Imager
0.75
0.5
VNIR
LLI
LWIR
SWIR

8. Coverage Analysis
6 Orbital Planes - 6 Satellites Per Plane
Sensor
Field of View
§ Assumptions:
q Sensor FOV: 40 Degree FOV
q Total Number of Sensors: 36
q Orbital Planes: 6
q Sensor Per Plane: 6
§ Conclusions:
q Coverage Complements
Geostationary Weather Satellites
q Ground Repeat Time Depends on
Satellite Precession
q 380 m in Vis-SWIR (760m LWIR)

9. § Assumptions:
q Sensor FOV: 80 Degree FOV
q Total Number of Sensors: 12
q Orbital Planes: 3
q Sensors Per Plane: 2
q Sensors Per Satellite: 2
7/17/13 9
Coverage Analysis
3 Orbital Planes - 2 Satellites Per Plane
§ Conclusions:
q Coverage Complements
Geostationary Weather Satellites
q Ground Repeat Time Depends
on Satellite Precession
q Resolution: 380m Vis/NIR/SWIR
(760m LWIR)
Equatorial
View
Polar
View

10. 10
MSIS Challenge
§ DMSP Satellites reach end of life around 2020. The Air Force SMC seeks
affordable space-based terrestrial weather solutions to meet DoD weather
requirements
MSIS Sensor Attributes
§ Capable
• Addresses Key DoD Weather Gaps
§ Cost Effective
• Uses Uncooled and Body Fixed Sensors to Reduce Complexity and Size
§ Compact
• Enables Use of Small Satellites and Hosted Payload Opportunities
• Small Satellite Approach Enables Satellite Constellation
• Constellation Provides Opportunity to Meeting Key Latency and Revisit Rate
Requirements
Summary