Glaciers%20and%20Ice%20Sheet%20Interferometric%20Radar

1
Glaciers and Ice Sheet Interferometric Radar

• ESTO Midterm Review
• January 10, 2008
• GSFC

2
GISIR/GISMO Team

• The Ohio State University (K. Jezek, J. Johnson)
• The Jet Propulsion Laboratory (E. Rodriguez, A.
  Freeman)
• The University of Kansas (S. Gogineni)
• Vexcel Corporation (X. Wu, J. Curlander)
• E.G.G Corporation (J. Sonntag)
• Collaborative with Wallops Flight Facility (W.
  Krabill)
• Science team members
• University of Utah (R. Forster)
• University of New Hampshire (M. Fahnestock)

3
Briefing Overview

• Project Overview
• September 07 Surface Conditions
• September 07 Flight Coverage
• P-3 Navigation
• Radar Performance, Calibration, Data
• Processing and Algorithms
• Summary, Plans and Budget

4
Global Ice Sheet Interferometric Radar (GISIR)
PI Prof. Kenneth C. Jezek, The Ohio State
University
Objective
Filtered basal inferogram
InSAR Concept

• Develop and test radars and algorithms for
  imaging the base of the polar ice sheets
• Investigate interferometric and tomographic
  clutter rejection and basal imaging methods
• 3-d topography of the glacial bed
• Images of subglacial conditions
• Develop multiphase center P-band and VHF radars
• Capable of sounding 5 km of ice
• Single and repeat pass interferometric operation
• Assess the requirements for extension to
  continental scale campaigns

Repeat pass tomography
Approach
Key Milestones

• Use available topography data to simulate
  interferograms for testing the InSAR and
  tomographic concepts.
• Modify the SAR simulator to include operating
  characteristics of several aircraft and several
  radar designs
• Develop UHF and VHF radars and antenna systems
• Test methodology by collecting data over the
  Greenland and Antarctic ice sheets
• Algorithm validation and sensitivity assessment.

1/ 06 Phase History Simulations and Algorithm
Testing 5/06 First flight test in Greenland
(Twin Otter 150 MHz) 7/06 InSAR algorithm
refinement 3/07 Radar and Antenna
Development 7/07 Tomography algorithm
refinement 9/07 Greenland Field Campaign (NASA
P-3) 5/08 Second Greenland Campaign (NSF Twin
Otter) 6/08 Algorithm and methodology assessment
7/08 Requirements doc. for continental scale
imaging
Co-Is E. Rodriguez, JPL P. Gogineni, U. Kansas
J. Curlander, Vexcel Corp. John Sonntag, EGG
C. Allen, U. Kansas P. Kanagaratnam, U. Kansas
TRLin 3
http//esto.nasa.gov
5
Major Accomplishments of the Past 6 Months

• Radar Installation and P-3 Test Flights in August
  07
• Greenland Field Campaign in September 07
• Prepared Field Campaign, Calibration Reports, and
  Data Summary Reports
• Submitted two abstracts to EUSAR
• Interferograms from 150 and 450 MHz data

6
Major Objectives for Remaining IIP

• Improve quality of 150 and 450 MHz Interferograms
• Compute topography at 450 MHz
• Complete clutter rejection trade study
• Validate conclusions about optimal platform
  (baseline, data rate) (May 08 field experiment)
• Complete back-projection vs SUSI processor trade
  study

7
Ice Sheet Physical Properties

• Differences between surface conditions in May and
  September

8
Ice Sheet Surface Conditions

• May 2006 Start of the melt period
• September 2007 End of melt period
• Summer 2007 most extensive melt since beginning
  of observations
• Surface roughness, near surface temperature
  differences (Report on in-situ surface-observation
  s posted to the web page).

Surface glazing during melt
9
DYE-3
Peterman Glacier
Jacobshavn
Scenes from Northern, West Central and East
Greenland September, 2007
Rinks Glacier
10
Melt End Dates
Passive Microwave Analysis
Mission scheduling likely avoided surface melt
conditions
11
September 2007 Data Coverage
12
Technical Objectives for September 07 Experiment

• 1) Acquire data over the May 2006 flight line to
  compare high and low altitude observations and to
  compare interferometry acquired with different
  baselines. Are results consistent with theory?
• 2) Acquire data at 150 MHz and 450 MHz along
  every flight line and compare backscatter and
  interferometric frequency response? Are the
  results consistent with theory?
• 3) Acquire data over areas where we expect to
  find subglacial water. Is water detectable
  either from backscatter maps or from topography?
• 4) Acquire data over regions of increasing
  surface roughness. This may require observations
  over heavily crevassed shear margins such as
  those found around Jacobshavn Glacier. Can we
  successfully implement interferogram phase
  filtering?
• 5) Acquire data for tomographic analysis
• 6) Investigate repeat pass interferometry over
  repeat periods of days.
• 7) Verify volume clutter is weak (all snow zones)
• 8) Collect data over thick and thin ice to test
  for absorption effects

13
Sept 07 flight lines
8 flights were completed. All glacier regimes
were sampled.
14
Sept 07
450 MHz High elevations Tomography
15
Sept 8
450 MHz, High Elevation Ice Stream
16
Sept 10 11 12
150/450 MHz High/Low Elevation GISMO/Depth
Sounder Modes Ice Stream
17
Sept 14 and 15
150/450 GISMO High/Low Elevation Outlet
Glaciers Tomography
18
Sept 14 and 15
19
Sept 18
150 MHz High Elevation GISMO Clusters
20

• GISMO Navigation Performance and Motion Files for
  September 2007
• John Sonntag
• EGG Technical Services, Inc.
• 10 January 2007

21
Navigation Techniques

• Two navigation tools available
• Soxmap
• Sample presentation shown at right
• Visual aid for flight crew
• Best for following curved path
• Course Deviation Indicator (CDI)?
• Can couple to aircraft steering
• Good repeatability for long straight lines

22
Steering Performance Examples

• Two examples from May 2007 ATM/CARDS project
• Shows respective steering performance of
  automated and hand-flown missions
• One mission used CDI coupled to aircraft's
  autopilot
• Other mission shown used Soxmap and was entirely
  hand-flown by the pilots

23
7 May 2007 Steering

• High-altitude P-3
• 16,000' outbound
• 26,000' inbound
• Similar to GISMO ops
• Aircraft steering almost entirely CDI-based,
  automated
• Steady-state cross-track error lt50 m almost 100
• Larger deadband at high altitude

24
070507 Cross-Track Error
25
070507 XTD Geographically

• Error exceeds 100 m at inflection points
  discrete course changes - because aircraft cannot
  turn instantaneously
• Steady-state error always better than 100 m
• Usually better than 25m, but not always
• Aircraft wingspan 30m

26
8 May 2007 Steering

• Low-altitude (1400' AGL) ATM laser-mapping flight
• CDI (science equipment) interfaces with P-3
  autopilot (aircraft avionics) to auto-steer
• P-3 autopilot inoperative during this flight
• Pilots still have our visual steering cueing
  available, either CDI or Soxmap

27
070508 Cross-Track Error
28
070508 XTD Geographically

• Aircraft was hand-flown for entire flight 8
  hours demanding on pilots
• Steering performance slightly degraded from
  previous case
• Deadband is 5-10 times larger than with
  operable autopilot
• Steering still within 100m 99 of time

29
September 2007 GISMO Steering

• Used precise steering throughout all flights
• Most demanding applications shown here
• Northeast ice stream mapping three parallel
  lines separated by 2 km
• Racetracks
• Mt Gogenini NW Greenland on 070907
• Swiss Camp 070914 and 070915
• Aircraft flies two parallel lines separated by 10
  km in an oval or racetrack pattern
• Racetrack flown four (3 on 070915) times, each
  time offset laterally by 25 m from previous
  racetrack

30
September 2007 GISMO (2)

• For best-quality automated steering
• Science steering equipment is distinct from
  aircraft systems
• They interface through the aircraft's instrument
  landing system (ILS) and autopilot
• We learned shortly prior to departure that
  aircraft autopilot was down and could not be
  repaired for deployment
• Entire campaign was hand-flown, no automated
  steering possible

31
070908 Ice Stream
32
070910 Ice Stream
33
070911 Ice Stream
34
070912 Ice Stream
35
Summary for Ice Stream Lines

• Some departures noted, mainly due to pilot
  workload or distraction
• 070907 center leg
• 070911 north leg
• 070912 north leg
• Most lines well within 50 m or so
• 070910 shows best steering performance over the
  ice stream

36
070907 Mt. Gogenini Racetrack
37
070914 Swiss Camp Racetrack
38
070915 Swiss Camp Racetrack
39
Summary for Racetracks

• In general, the fine 25 m separation of the
  parallel lines shows the limitations of manually
  steering a large aircraft precisely
• We would expect much better performance with an
  operable aircraft autopilot
• 070907 racetrack does not appear useful
• Potentially useful segments for tomography
• 070914 north legs 2-3, portions of south legs
  2-3-4
• 070915 north legs 2-3, portions of south legs 1-2

40
Motion Files (1)

• We provide motion files to the GISMO team 6
  degree-of-freedom time series describing position
  and orientation of aircraft
• Motion files are a post-flight combined product
• Litton 100 inertial navigation system for
  orientation _at_200 hz
• Differential GPS for position _at_ 2hz
• GPS time series is quadratically interpolated to
  INS timetags to yield a 200 hz product
• Time tags are not regularly spaced LN100
  firmware
• Time tags are in UTC time scale UTCGPS-14 sec
  currently

41
Motion Files (2)

• We can create quick-look (within 1-2 days after
  flight) motion files and final (2 weeks) motion
  files same INS data stream but different
  techniques for GPS trajectory
• Estimated accuracies
• Orientation 0.01 degrees
• Latitude and longitude 2 cm final, 5-20 m quick
• Height (relative to WGS-84 ellipsoid) 10 cm
  final, 20-100m quick
• Initial motion files had 14 sec embedded time tag
  error
• Fixed after October 2007
• Files with error end in .motion, corrected
  files end in .motion2

42
GISMO Radars, Calibration and Results
S. Gogineni, F. Rodriguez, C. Allen, C. Leuschen,
A. Hock, Jilu Li , K. Marathe, V. Jara, J.
Ledford and Hee Chun CReSIS University of Kansas
43
Radar System Accomplishments

• Full recovery from April 2007 power surge failure
• Obtained 150 and 450 MHz data in GISMO and Depth
  Sounding Mode
• Field report prepared and posted to web
• Distributed Data to Team
• Prepared Data Calibration Report

44
P-3 Radar Installation
45
Radar Power Amplifiers (upper left) Radar
control unit, receivers, and test equipment
(right)
46
Radars Proposed and Developed
1Additional gain achievable during post
processing. Post processing gain depends partly
on scattering characteristics of the surface.
47
Low-Range Sidelobes
Compressed ocean-surface return
48
Tests at SPRINT EMI Facility
Radar performance at 150-MHz degraded by
Ethernet switch by about 15 dB Accelerometers
were turned off when we suspected they might be
introducing RFI
Operating range
Base-band signal from 450 MHz No RFI problem at
450 MHz
Base-band signal from 150 MHz
Different antenna types were tested
49
Radar Calibration

• Radar calibration
• Delay line
• Network analyzer
• Ocean surface
• Network analyzer and Delay line measurements are
  in good agreement
• 6-16 deg at 150 MHz
• 0.4-34 deg at 450 MHz.
• Ocean data are being analyzed

50
Depth Sounder Results at 150 MHz
Data are not corrected for aircraft height
variations
Artifacts of data detrending to enhance layers
Very strong bed echoes S/N gt35 dB
51
Backscatter model results
52
Model and Experimental results
150 MHz
Depth Sounder
150 MHz, GISMO Single Ant. Ice Stream 500 m
20 dB
450 MHz, Depth Sounder Ice Stream 500 m
Results consistent at 150 MHz Clutter at 450 MHz
(?)
53
2580 m Ice thickness
6800 m PA
GISMO
GISMO
6800 m PA
450 MHz
150 MHz
Ice Stream
49 km
2580 m ice thickness
500 m above surface
500 m above surface
Depth Sounder
GISMO
54
2580 m Ice thickness
6800 m PA
6800 m PA
GISMO
GISMO
Ice Stream
450 MHz
150 MHz
4 km
500 m above surface
500 m above surface
GISMO
Depth Sounder
55
High Elevation 150 and 450 MHz Ice Stream Data
450 MHz GISMO Estimated attenuation through the
ice 84 dB (1.8 dB/100m)
150 MHz GISMO Estimated attenuation through the
ice 68 dB (1.4 dB/100m)
56
Summary

• Successful data collection
• Radar performance as designed
• 150-MHz radar performance comparable to May 06
• 150-MHz radar sensitivity reduced by about 15 dB
  from Sept 07 Plan
• gt RFI from Lasers and Ethernet switch
• Accelerometers developed and integrated
• Could not use during the entire experiment
• RFI
• Possibly from USB power supply used to power
  accelerometers
• Data are copied and distributed to everyone
  within six weeks
• Calibration data are being analyzed
• RFI characterization completed
• Adaptive filters and techniques will be
  developed to reduce RFI
• Motion and calibration data to be incorporated
  into data processing algorithm

57
Processing and Algorithms
58
Processing Accomplishments

• Algorithm Design Review June 07
• Data review meeting November 2007
• Data review report prepared and posted to web
• New SAR processing concept proposed to improve
  September data analysis
• Processing Team Meeting January 08
• Rodriguez et al paper nearing completion
• Abstract Submitted to PARCA meeting

59
InSAR Processing Review

• Xioaqing Wu
• Vexcel Corporation
• GISMO Processor and Results
• August 7, 2007

60
May 06 GISMO - Interferogram
3.91 m baseline
5.8 km in air
1.3 km in air
61
Left-Right separation Theoretical analysis
S1
S2
x
B
r1
r1
r2, right
H
r2, left
P
Q
h(x)
62
Left/right side interferogram separation
Left side interferogram
Right side interferogram
1.3 km in air
63
GISMO Equation
B
?
?
r2
r1
sin?1 nsin?2
?
64
May 2006 GISMO Flight, 150 MHz, InSAR Swath
Measurements of Topography Beneath the Greenland
Ice Sheet
3.91 m baseline results
Basal topography measured along a 25 km flight
line and across a 3 km swath over the western
Greenland Ice Sheet in May 2006. Thickness was
measured using an airborne 150 MHz Synthetic
Aperture Radar. The data were processed to
simultaneously image the left and right sides of
the aircraft. Thickness was subtracted from
ICEsat surface elevation data to compute basal
topography.
left
right
(Original 5 km across track swath trimmed to
remove some noise spikes)
65
Left/right side interferogram separation
Left side interferogram
Right side interferogram
7.38 meter baseline
1.3 km in air
66
2007 September data processing

• Synchronization validation
• Data calibration
• Some processing results

67
Synchronization validation

• Synchronization between the motion data and the
  radar raw data is verified using the Sep. 15
  ocean data.

Distance between radar and nadir surface measured
from range compressed radar data
INS/GPS measured sensor altitude
68
Data calibration

• Validate the cross track relative locations of
  antenna elements
• Measure channel dependent relative time delay

Left side
Right side
R3 12.23
R5 13.95
R1 -13.08
T0
T1
R0 -13.95
-11.39
11.39
R4 13.08
R2 -12.23
GISMO
Tz1-Tz0 Rz1-Rz0 Rz2-Rz0 Rz4-Rz3 Rz5-Rz3 Rz3-Rz0
? 0.0106m -0.2239m 0.0361m -0.1976m ?
450 MHz
69
Difficult to estimate the relative time delay
between left and right wing channels (450 MHz)

• Due to effective baseline of minimum 11.39m, the
  fringe rate at the nadir is too high for a
  reliable phase difference estimation

Baseline of 0.86m
4.2 km
Baseline of 11.39m
5.8 km in air
70
Validate cross track relative corrections Sep.
15 GISMO mode ocean data
Roll angle
Phase difference in range compressed data
Phase difference in azimuth compressed data
71
450 MHz Depth Sounder Mode Calibration
Range compressed data

• - Use September 10 surface data (file number 310)

Azimuth compressed data
R4 -13.08
Rz3-Rz2 Rz4-Rz2 Rz5-Rz2
0.0169m -0.2681m -0.2757m
R2 -11.39
R5 -13.95
R3 -12.23
T
72
150 MHz data calibration using ocean data

• Interferometric phase before and after roll and
  baseline corrections

Rz1-Rz0.1964 m Rz2-Rz0 -0.087136 Rz4-Rz3
0.0217 Rz5-Rz3-0.2691
Phase difference measured from range compressed
data
Phase difference measured from azimuth compressed
data
73
450 MHz Interferometric Results

• 450MHz GISMO data (Sep. 15) 86 cm baseline

Rinks Glacier Region
5.8 km in air
Surface clutter
74
450 MHz Interferometric Results
11.39 m effective baseline 3 interferograms
added Note off nadir clutter rejection

• 450MHz GISMO data (Sep. 15)

Clutter reduced through registration and averaging
75
NASA East Camp Region
File 306-314
Effective Baseline 1.3 m

• 450MHz Depth mode data (Sep. 10)

5.8 km in air
76
Results With Increasing Baselines

• 450MHz Depth mode data (Sep. 10)

43 cm
86 cm 1.3 m
18.9 km
2 km in air
NASA EAST CAMP
77
Ice Stream Interferograms

• 450 MHz Depth mode data (Sep. 10)

43 cm 86 cm
1.3 m
23 km
2 km in air
Ice Stream
78
450 MHz Topography

• Topography calculation will be done after further
  improvement in interferogram SNR
• Approaches include
• Average multiple interferograms with different
  baselines
• Average ping pong interferograms with same
  baseline
• Increase number of azimuth looks (SUSI)

79
GISMO Progress in Processing AlgorithmsSquinted
Unfocused SAR Interferometry(SUSI)

• E. Rodríguez
• Jet Propulsion Laboratory
• California Institute of Technology

80
Motivation for Last 6 Month Activities

• Processed interferometric data for the last
  campaign has only become available from Vexcel
  during the last month
• Demonstration of clutter rejection algorithms
  developed in the previous 6 months on real data
  requires interferometric processed data
• Examination of past data showed that it would be
  very useful to obtain additional looks to
  reduce interferogram phase noise
• A new Interferometric Sounder processor idea
  (SUSI) was developed to optimize the number of
  looks which could be obtained from the sounder.

81
Limitations of Conventional Processors

• Conventional processors obtain looks by
  processing data to high resolution and then
  spatially averaging to obtain looks.
• This has the following limitations (explored in
  detail below)
• Loss of information regarding the scatter angular
  variation
• Sensitivity to small scale surface topography
• Sensitivity to non-straight-line motion
• Complicated ray-bending calculations required to
  form the exact match filter
• Unused looks

82
Loss of information regarding the scatter angular
variation

• Forming a high resolution conventional aperture
  uses the information from all look directions
  from which any point is viewed
• Scattering angular variation information is lost
• The effective aperture length is limited by the
  width of the scattering function, which, in the
  near-nadir direction, can be small, leading to
  degraded azimuth resolution

83
Sensitivity to small scale surface topography

• The presence of topographic variations ?h in the
  ice sheet lead to phase errors
• These phase errors lead to defocusing and gain
  loss. The gain loss is approximately given by
• Where ?h is the ice height std over the aperture.
  For example, a 10cm variation leads to a loss of
  10dB in coherent gain! gt keep apertures short!

84
Sensitivity to non-straight-line motion

• There can be significant non straight-line motion
  during a long aperture formation.
• Motion errors can be compensated by
  back-projection
• However, the meaning of the interferometric
  baseline is not clear when significant motion
  occurs
• A well defined interferometric baseline is
  required for topographic reconstruction

85
Complicated ray-bending calculations required to
form the exact match filter

• The solution of the ray-bending equations is
  non-linear and requires significantly added
  computation to calculate the ray-bending delays
  for back-projection
• Neglecting ray-bending effects is not possible
  when trying to form large apertures (see
  following viewgraph)

86
Ray-Bending vs Straight Azimuth Compression

• Platform height 8 km
• Ice depth 2 km
• Cross-track distance 1 km
• Wavelength 70 cm
• -- Ray-bending point target response
• -- Straight-line point target response

87
Unused looks!

• The net effect of these problems is that
  typically only short apertures are formed,
  leading to fewer looks than could be obtained and
  noisier interferograms.
• It is highly desirable for GISMO applications to
  recover additional looks, if possible
• The VHF view angle is 30 deg
• The UHF view angle is 10 deg
• Currently view angles are 1 deg

88
The SUSI Concept
Short aperture n
Short aperture n1
Short aperture n2

• Form many short coherent apertures and steer each
  aperture so that all points in the ground are
  viewed from multiple incidence angles.
• The subapertures are short enough that most ice
  sheet surface variations will have a small impact
  on the compression gain.
• Form interferograms from small aperture pairs
• Average interferograms over small angular regimes
  to obtain additional looks
• Average heights from multiple interferograms to
  obtain further noise reduction.

89
Limiting the aperture size

• Limit the aperture size so that phase from any
  given point in the swath can be approximated by a
  linear ramp
• Focus synthetic array by simple phase ramp
  compensation
• Phase ramp can be accurately calculated
  analytically gt fast!
• Approximate azimuth-resolution obtained

90
How many looks can be obtained?
91
Simulation example range compressed data
This example shows the range compressed returns
from 5 targets at the same depth, but different
cross track distance. In this example, the
antenna pattern and sigma0 angular variations
have not been applied. This presents a worst case
in terms of sidelobe performance, but is easier
to visualize the change in sidelobe position with
viewing angle.
92
The center aperture conventional unfocused SAR
processing
93
Aperture 1
94
Aperture 10
95
SUSI Processor Status

• The theory and formulas of the SUSI processor
  have been developed
• The compression aspects of the processor have
  been demonstrated using simulated data
• The demonstration of the processor with real data
  has just started with the availability of the
  range compressed data
• The next period will concentrate on the
  interferometric aspects of SUSI and on optimizing
  the implementation
• The goal is to process all good data sets with
  SUSI and compare against Vexcel processor

96
Conclusions

• JPL now has 4 people working 1/2 time on the
  GISMO IIP, and are catching up to the plan
• The next phase of work will concentrate on
  clutter rejection and SUSI improvements
• Depending on future flight plans, a no-cost
  extension may be requested to be able to process
  future collected data sets.

97
Proposed Field Campaign for May 2008
98
Field Experiment in April/May 2008

• We will take advantage of an NSF/CReSIS sponsored
  field program in Greenland during April/May 2008
• We will deploy the 150 MHz radar with improved
  antennas and with improved overall performance by
  reducing noise sources
• We will fly a line in GISMO mode along the
  Jacobshavn Glacier towards the ice divide
• The primary objective will be to investigate
  platform attributes and system parameter trades
  (baseline, data rate, additional antennas,
  improved radar sensitivity)

99
Summary, Plans Budget
100
IIP TRL Objectives
Item Entry TRL Justification Exit TRL Success Criterion
IFSAR processing under ice 3 IFSAR processing has only been demonstrated for land surfaces. Imaging under ice requires new techniques to account for ray bending and ice surface. 5 Successfully image basal layer from data collected in deployments (low altitude flights)
IFSAR clutter rejection 3 Extends angle of arrival techniques to develop a new technique for clutter rejection. 5 Successfully reject clutter from high altitude flights results agree with sounder low altitude flights
Ionospheric effects 3 Calibration techniques exist for data far from nadir. They will be extended to near-nadir polar data. 5 Simulation and theoretical results to validate calibration technique
Our goal is to advance the technique to a TRL
level 5 or 6, so that our instrument could be
ready to go to a phase A/B after completion of
the IIP. We estimate that the schedule and
resources required for this are compatible with a
NASA ESSP class mission.
101
2008 TRL Assessment
Item Current TRL Progress Exit TRL Success Criterion
IFSAR processing under ice 5 Demonstrated ability to acquire SAR SLC image data from basal ice (estimate TRL 5 by end of year 2) 5 Successfully image basal layer from data collected in deployments (low altitude flights)
IFSAR clutter rejection 4 Simulations demonstrate that IFSAR filtering technique is feasible (estimate TRL 5 by year 2/3) 5 Successfully reject clutter from high altitude flights results agree with sounder low altitude flights
Ionospheric effects 3 Calibration techniques exist for data far from nadir. They will be extended to near-nadir polar data. 5 Simulation and theoretical results to validate calibration technique
102
Project Tasks(gray change green complete
orange in progress)

• Year 1
• Science and Management (OSU) Convene Science
  Team conduct initial design review refine
  project plan compile information on ice
  dielectric properties and ice sheet physical
  properties such as surface roughness and slope.
  Prepare reports as required by NASA
• Radar Development (University of Kansas a)
  Design of new set of optimized antennas We will
  build a model structure and measure its
  electrical performance. We will identify and work
  with a contractor to build the antenna
  installation mounted under the wings and flight
  test it in collaboration with engineers at NASA
  Wallops at 150 MHz. Flight test at 450 MHz b)
  End-to-end simulation of the system including
  antennas.
• Algorithm Development Develop a motion
  compensation processor and a time-domain
  (back-propagation) IFSAR processor. Use legacy
  code from the GeoSAR and MOSS IIP projects. (JPL
  planned for April 07) b) Prototype first
  version of the interferogram filtering code
  (JPL) c) Modify simulation software and
  generate simulated IFSAR returns from basal and
  surface layers (Vexcel) and evaluate the filter
  performance on the simulated data.

103
Project Tasks

• Year 2
• Radar Development Build sub-system and assemble
  the complete system.(150 MHz complete, 450 MHz)
  Perform laboratory tests using delay lines to
  document loop sensitivity,radar waveforms and
  impulse response.
• System Integration (KU, WFF, Aircraft Operator)
  a) Install the radar and navigational equipment
  on P-3 or similar aircraft and conduct flight
  tests over the ocean. (completed at 150 MHz
  September 07 at 450 MHz
• Algorithm Development. Develop a strip IFSAR
  processor and compare against the results of the
  exact time-domain processor. (Concept for a
  multi-incidence angle processsor capable of
  computing additional geophysical characteristics
  and reducing noise by increasing number of looks)
  Iterate the clutter removal algorithm based on
  experimental results (JPL). Develop software and
  apply software to process multiple 2-D complex
  SAR images coherently (Vexcel).
• Data acquistion and Analysis Field experiments
  over the ice sheet (Sept. 07) Finalize
  interferometric SAR processor and pre-processor
  and process data from first campaign (JPL).
  Extract basal topography from result. Iterate
  interferometric filter design based on assessment
  of the results.
• Science and Management Participate in field
  measurements Conduct design and performance
  review assess quality of results in context of
  science requirements. (Completed for Twin Otter
  In progress for P-3)

104
Project Tasks

• Year 3
• Data Acquisition and analysis Conduct second
  airborne campaign (May 08) Reduce and analyze
  data. Develop software and apply software to
  process multiple raw data acquisitions
  tomographically. Apply linear beam forming
  techniques (Demonstrated with twin otter).
  Extract basal topography from result (150
  complete 450 to be done). Compare results of
  SUSI and time-domain SAR processors.
• Mission Design Spaceborne mission design based
  on the experimental results.
• Science and Management Participate in final
  field experiment convene final review develop
  mission concept in terms of science requirements
  and experimental results prepare final reports.

105
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107
Proposed Schedule for No Cost Extension
108
Publication and Presentation Plans

• Submit algorithm paper (January 08)
• Submit SAR processor comparison paper (June 08)
• Submit geophysical analysis paper (September 08)
• Abstract submitted to February PARCA meeting
• Abstracts submitted to EUSAR Meeting
• GISMO wrap-up at Fall AGU

109
Budget Summary
110
Budget Issues

• A 2nd, year 3 airborne experiment will occur near
  the end of the project. Given current spending
  projections, a no-cost extension to the end of
  the calender year is requested to allow for
  analyzing data from the experiment.
• Request that 30k remaining at WFF be used to
  support Twin Otter and related EGG field costs
  in May 08
• Request that remaining aircraft funds held at
  ESTO plus overhead (119,995) be sent to OSU for
  reallocation to team in support of May 08
  deployment and analysis.

111
Proposed Task Modifications

• Vexcel
• May 08 data processing
• Refraction included in processor
• Software distribution
• JPL
• Concentrate on clutter rejection and refraction
  algorithms. Investigate increasing number of
  looks to improve interferogram SNR (SUSI).
• KU
• Participation in May 08 airborne campaign
• Calibration and Data Distribution
• OSU
• Participation in May 08 airborne campaigns
• Data processing
• Final reports
• EGG and Wallops Flight Facility
• Participate in May 08 deployment