atmosphere as a sensor (atmosense) - darpaatmosphere as a sensor (atmosense) major charlton...

Atmosphere as a Sensor (AtmoSense)

Major Charlton “David” Lewis, II, PhD, USAFDARPA/DSO

Proposers Day Brief

14 Feb 2020

AtmoSense will develop the fundamental science needed to model, simulate, predict, and measure energy propagation from near earth disturbances.

DISTRIBUTION A. Approved for public release: distribution unlimited.

2

Purpose of this briefing: • Discuss program objectives and structure

BAA takes precedence• These slides are meant to provide background and clarification only• Please consult published BAA for final program specifics

Until the deadline for receipt of proposals • Open communications between proposers and the program manager are encouraged • Information given to one proposer must be available to all proposers • The best way to get a question answered is to email it, and to retrieve your answer from the Questions

and Answers list via the DSO solicitations website• Note that any question that contains distribution restrictions, such as “company proprietary,” will not be

answered

Ground Rules

Questions: [email protected]


mailto:[email protected]

3

• Part I: AtmoSense Concept• Part II: AtmoSense Program Structure

Overview


4

Part I: AtmoSense Concept


Ionosphere

Mechanical wave propagation

�⃗�𝑣

Ground-based source

MechanicalWake Propagation

ElectromagneticallyReactive

Air-based source

AtmoSense will understand the fundamentals of energy propagation throughout the atmosphere to enable its use as a sensor.

Mesosphere“Ignorosphere”

Stratosphere

ExamplesAcoustic/Ionospheric DisturbancesPlasma compression against magnetic field launches wavesGravity/Acoustic-Gravity WavesLongitudinal/acoustic perturbations that travel upwards through the mesosphereAcoustic-Seismic CouplingAcoustic perturbations travel downwards and penetrate groundElectromagneticsObjects and the atmosphere scatter ambient/present EM energy that could be captured in a multistatic way InfrasoundLarge-scale phenomena produce tropospheric disturbances

5

AtmoSense Program Goal


6

What do we know today in the observational literature?

TNT Equivalent Energy (Tons)

Pert

urba

tion

Size

(TE

CU)

Thunderstorm

Tohoku(9 mins)

Hurricane

Volcano

Tornado

100 101 102 103 104 105 106 107

10-2

10-1

100

101

Sulawessi (2009)

Falcon 9(5 mins)

Ionospheric Signature Observations

UndergroundNuclear Explosion(12 mins)

Chelyabinsk (2013)(8.3 mins)

Tunguska (1908)

Himawari (2018)

Ordnance(5.7 mins)

MillraceHE Test

10-3

WWIIBombing

Mining Operations

Energy propagates from the Earth’s surface to the ionosphere, but the specifics of how is not known well enough to use the atmosphere a sensor.

Tornado Rocket Launch

TECU = 1016 e-/m2(xx mins) = time from event to measured ionospheric perturbation

• It’s clear that mechanical signals travel from the surface to the ionosphere, but are they exploitable?

Why don’t we do it today?• Current SOA only gives us after-the-fact observations and

analysis and relies on limited phenomenologies.• For example, given an ionospheric signature, we cannot

differentiate between energetically equivalent sources or geolocate events accurate through atmospheric M&S.


What might be the smallest source detectable on the atmosphere?

7

How might we exploit these energy signals?

An Idea: Passive multistatic wave detection via mechanical and electromagnetic sensing modalities

Analogy #1: Boat wake (sustained) Analogy #2: Ripple in a pond (impulse/shock)

BoatAmplitude Sensor

Wake

Sensor

Wake detection “Triangulation” to detect distance and strength of perturbationTornado

Bolide


8

How could we think of the Atmosphere?


A massive information reservoir

Entropy

• Hypothesis: your size, location, direction, and speed information propagate at the speed of sound• The upper atmosphere seems to readily support information propagation• Global sensor that is already in orbit!• You cannot readily hide your mechanical perturbations to the atmosphere

A massive entropy reservoir• Example sources of Entropy: turbulence, winds aloft, changing temperature profiles, shear,

compressibility, Coriolis forces, seasonal variability etc. etc.• Lower atmosphere has a low passband structure, does this apply to the upper atmosphere?

What information can be extracted? What is the smallest detectable transient source disturbance?

Signal

9

Basic science questions needed to be addressed:

o What is the nature of the transmitted signal?o How does source generation influence disturbance dynamics from near field

(meters) to far field (100 km)?

o What is the mode structure (mechanical and electromagnetic) of the mesosphere and lower ionosphere?o What is the passband structure of the mesosphere?o How does atmospheric ducting influence energy propagation?o What type of energy loss occurs during neutral atmosphere-ionospheric coupling?

o What dynamic variables are best measured and at what altitude to capture source disturbed information?o Can ambient RF (natural or human-made) be used to detect altered propagation

paths?o What is the influence of the day/night terminator and is it exploitable?o How does daytime/nighttime atmosphere affect what is best measurable?

What basic scientific understanding do we need to enable AtmoSense?

9

Bolide

frequency

pow

er

Explosion

frequency

pow

er

Background

frequency

pow

er

Background

???

frequency

pow

er

Irregularity Spectrum

???

frequency

pow

er

Earthquake

frequency

pow

er


Analogy #3: Communication conveys information

*Not to scale

Transmitter Signal Receiver

Meteorological/geophysical source

Transient Disturbance Atmosphere

Exosphere

10

Limitations on the current state of the art (Model & Simulation)

Disturbance Generation:• Computational domain on order ~10-100s of meters• Assumes constant gravitational field• Assumes uniform atmospheric background• Computational resources scales poorly with physical domain

• Different geophysical/meteorological sources demand different ansatzes:

• Tornado Hurricane Bolide• Thunderstorm Earthquake Mining Operations• Volcano Tsunami etc.

Acoustic Wave and Electromagnetic Propagation:• Troposphere/Stratosphere (NWP)

• Standard time integrators can’t handle both fast and slow wave modes• Often assumes disturbances travel slower than speed of sound• Assumes a statistical atmospheric background

• Mesosphere• Lower atmospheric assumptions break down in mesosphere• Plasma wave dispersion depends on non-uniform plasma density

• Ionosphere• Bottom side is often assumed to be a “frequency mirror” without irregularities• Ray tracing assumptions invalid for medium to small scale irregularities

Near-Field Far-FieldStrong Shock Weak Shock Linear/Non-linear Waves

AtmoSense will understand the evolution of energy from near-field source generation to far-field signal propagation through multiple atmospheric layers

Foundational question: How do we evolve assumptions over spatial scales?

Bolides Breaking Mountain Waves

Atmospheric M&SEvent Source M&S


11

Limitations on the current state of the art (Sensors & Characterization)

Ground Measurements:Lidar, Radar, Infrasound, Acoustic, Seismic• Troposphere filters out higher frequencies• Traditional focus on infrasound surface propagation

Ionosphere

Mesosphereaka “Ignorosphere”

Stratosphere

Troposphere

0 km

17 km

50 km

100 km Receiver (space)

Receiver (air)

GPS TEC:• Poor job of detecting upward disturbances• 15 minute cadence• Receivers owned by ICG consortium

Remote Sensing (NASA):• Ozone can block UV• Limited IR atmospheric “windows”• Designed to observe natural timescales

Receiver (ground)

Transmitter (air)

AtmoSense will discover the background mesospheric spectrum and develop novel sensing modalities to exploit the atmosphere as a global receiver

Transmitter (ground)

Background

???

frequency

pow

er

“Too low for satellites, too high for balloons”


12

What do we think is now possible today? Holistic atmospheric approach

F-Region

E-Region

D-Region

High-Fidelity Source Modelingfrom Geophyics/Meteorology Communities

Nascent ability to measure the whole atmosphere at once


Airglow

MultiStatic Passive HFSounding

Opportunity to M&S and observe a singular event through the whole atmosphere

Tropospheric Modalities used in new ways

Acoustic Gravity Waves(2nd, 3rd, 4th)

Stoke’s Scattering

VLF From Lightning

“PV=nRT”Measurements

Lower SWAP Lighter-than-air VehiclesImproved LoiterChemical Species

Composition

Forw

ard

Solve

rs

Inverse/Reverse Solvers

+

Push Atmospheric modeling beyond Infrasound and Gravity Waves

SOA M&S and Solvers to drive new modalities

doi: 10.1029/2019JA027200

doi: 10.1121/1.5140449

13

Part II: AtmoSense Program Structure


14

AtmoSense Technical Areas

Technical Areal #1: Develop the model & simulation and analytic approximations to connect near-field disturbances to far-field atmospheric acoustic and electromagnetic perturbations

What is the nature of the transmitted signal?

Technical Areal #2: Experimentally characterize the background and mode structure of the mesosphere and lower ionosphere

What is the mode structure (mechanical and electromagnetic) of themesosphere and lower ionosphere?

Technical Areal #3: Develop new sensing modalities and exploit natural/non-natural emitters to detect mechanical and electromagnetic variations of the atmosphere.

What dynamic variables are best measured and at what altitude to capturesource disturbed information?


15

AtmoSense Structure

Phase 1: Concept Development

Phase 2: Proof of Principle Field Testing

27-months


12-months

• Only interested in meteorological and/or geophysical sources

• Proposer’s are encouraged to form teams and address all Technical Areas

• An Independent Validation & Verification (IV&V) team will help assess performance through all milestones and determine entry into Phase 2

Proposal Instructions

• Apply Phase 1 S&T to field testing and analyze results against direct measurement techniques

• “Static” source e.g. mining operations• “Dynamic” source e.g. thunderstorm

• Notionally, three field tests three months apart

• Dependent on performer selected source/art-of-the-possible

An aggressively phased basic research program to move from “impossible to doubtful”

39-Month Program w/2 Phases

FY20 FY21 FY22 FY23

AtmoSense Schedule and Milestones

24-MonthMilestone

Test Series12-MonthMilestone

IV&V Team

Phase 1: Concept Development Phase 2: Proof of Principle Testing

Kickoff

Field testing campaignsDisturbance Dynamics M&S

Disturbance Dynamics + Background M&S

Atmospheric Monitoring and Background Observation Campaign

Sensor Modality Sensitivity Improvement

Final

• Controlled explosion series• Storm systems over US• Pacific Rim earthquakes• Breaking mountain waves

TA#3: Sensing modalitiesNew Sensor Concept Discovery/Development and

Laboratory Testing

Repurpose Traditional Modalities

TA#1: Source disturbance M&S (near-field to far-field)

Dow

n se

lect

, Pro

posa

l Pre

para

tion,

Cont

ract

ing

Actio

ns

TA#2: Mesospheric characterization and modal support discovery


17

AtmoSense Milestones and Metrics


TA1 Milestones & Metrics

ChosenDisturbance

Comparison Metrics to all Observed Slant dTEC Single Rx Sites All Rx Sites dTECu = 0

Time of Flight/Onset of Disturbance (Time)

Duration of Disturbance(Time)

Max/Min Amplitude of Disturbance(dTECu)

Temporal Track(dTECu)

Duration of Total Disturbance(Time)

Threshold +/- 15% (absolute)

+/- 15%(absolute)

+/- 25%(relative)

+/- 70%(relative)

+/- 20%(absolute)

Goal +/- 5%(absolute)

+/- 3%(absolute)

+/- 10%(relative)

+/- 20%(relative)

+/- 10%(absolute)

12-month milestone: Reproduce in M&S ionospheric TEC signatures ofmeteorological or geophysical source phenomena that have been observed and reported in literature.• Earthquakes• Thunderstorms• Hurricanes• Tornados• Bolides• Other sources handled on case by case basis with respect to observed evidence available ToF

Min Amplitude

Max Amplitude

Disturbance Duration

Time Track

Metrics

Phase 1 Concept Development

doi: 10.1029/2019JA027200

To be achieved at 24-months

18



TA1 Milestones & Metrics24-month milestone: Refine and expand 12-month M&S with background spectrum.Metric: IV&V verification of M&S ability to incorporate background spectrum based on TA2 measurements.

ChosenDisturbance

Ionospheric MeasurementsComparison Metrics to all Observed Slant dTEC Single Rx Sites

Neutral Atmospheric Measurements

Time of Flight/Onset of Disturbance (Time)

Duration of Disturbance(Time)

Max/Min Amplitude of Disturbance(dTECu)

Temporal Track(dTECu)

Duration of Total Disturbance(Time)

HF ScatterDoppler Shift

(?)

Pressure (?)

Temperature (?)

Density(?)

Derivative measurement #1

(?)

Derivative measurement #2

(?)

Threshold +/- 15% (absolute)

+/- 15%(absolute)

+/- 25%(relative)

+/- 70%(relative)

+/- 20%(absolute)

Goal +/- 5%(absolute)

+/- 3%(absolute)

+/- 10%(relative)

+/- 20%(relative)

+/- 10%(absolute)


Additional variables to be measured in Phase 2

Reasonable to assume if Goal TEC metrics are achieved then the propagation of energy in the troposphere, stratosphere, and mesosphere are correct to drive needed sensor sensitivities.

19



TA2 Milestones & MetricsQuarterly milestones: Report of atmospheric and background measurement campaign results shared with TA1, TA3 and IV&V performers at technical interchange meetings.

Metric: IV&V verification that quality of data is meeting program needs.

TA3 Milestones & Metrics12-month milestone: Present and technically justify the measured/projected performance and value of atmospheric sensing techniques and modalities for the purpose of the assessment by DARPA and the IV&V Team.

Metric: IV&V assessment that sensor modalities are likely to achieve the sensitivity needed to exploit atmospheric and ionosphericphenomena.

24-month milestone: Further refine promising sensing modalities, including incorporation of background characterization and results of TA1. Present and technically justify recommendations of atmospheric and ionospheric sensing techniques to DARPA and the IV&V Team for Phase 2 field testing.

Metric: IV&V assessment that sensing modalities are suitable for field testing.


20

• Performers will receive Proposal Instructions approximately 18 months into the program and a draft detailed Phase 2 proposal will be part of the 24-month milestone review by the IV&V team.

• Proposers should still estimate cost for Phase 2 fielding testing with the assumption that Phase 1 proposed work is successful.

• DARPA does not expect the cost proposal for Phase 2 to be as detailed as Phase 1.

• Notionally assume 3 test campaigns approximately 3 months apart. Note: the details will be dependent on the source chosen for Phase 2 as Phase performance will dictate what is feasible.

• The technical areas will re-focus their respective science and technology on simulating, predicting, and observing the mechanical and electromagnetic perturbations.

• Final Exam: After data collection and analysis how well can using the Atmosphere as a Sensor geolocatethe source of the disturbance compared to direct measurement techniques?

AtmoSense Phase 2

Phase 2 Proof of Principle Field Testing


21

• Proposers Day: 14 February 2020

• BAA Release: 4 March 2020

• Abstracts Due: 13 March 2020

• FAQ Submission Due: 10 April 2020

• Proposal’s Due: 22 April 2020

• Kick-off: ~Nov/Dec 2020

AtmoSense Key Dates


22

AtmoSense Points of Emphasis


TA1

TA2

TA3

AtmoSenseWhat is the nature of the transmitted signal?

What is the mode structure (mechanical and electromagnetic) of the mesosphere and lower ionosphere?

What dynamic variables are best measured and at what altitude to capture source disturbed information?

How will your ideas and technologies help us answer the question,“Can the atmosphere be used as a sensor to find & fix geophysical/meteorological sources?”

23

The AtmoSense Grand Vision

AtmoSense is a fundamental science program that will enable novel ways to sense activity that occurs in the Earth’s atmosphere

AtmoSense exploits signatures that are fundamentally different from those relied upon by direct traditional approaches


www.darpa.mil

24DISTRIBUTION A. Approved for public release: distribution unlimited.

atmosphere as a sensor (atmosense) - darpaatmosphere as a sensor (atmosense) major charlton...

Documents