Design to Improve the Productivity and Execution of Gravity Surveys

Gravity for the Redefinition of the American Vertical Datum GRAV - D

Design to Improve the Productivity and Execution of Gravity Surveys

Evan DemickKyle LuukkonenSadeep NonisYuri Zhylenko

Sponsor: Sandra Preaux - NOAA

https://hazards.fema.gov/femaportal/wps/portal/!ut/p/c5/04_SB8K8xLLM9MSSzPy8xBz9CP0os3gDCyNfM_OAYGcLA2cjdwMnwwADKADKR2LKmxrD5fHrDgfZh18_WB4HcDTQ9_PIz03Vj9SPMscwxSLABGZKZE5qemJypX5BboRBlkmoIgDulWf9/dl3/d3/L0lDU0lKSWdrbUNTUS9JUFJBQUlpQ2dBek15cXpHWUEhIS80QkVqOG8wRmxHaXQtYlhwQUh0Qi83XzA4Mk02N1BTQzgwQzJHMEI5UDQwMDAwMDAwLzdoYllFNjcxNDAwNTQvc2EubGVnZW5kLkxlZ2VuZEZvcm1BY3Rpb24!/#7_082M67PSC80C2G0B9P40000000

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1AgendaContext ReviewStakeholder AnalysisProblem & Need StatementsMethod of Analysis & SimulationRecommendation & Conclusion22Collection of measurements of the acceleration of gravity.Accelerations are used to model the earths geoid. The geoid model is used to determine elevations.Mountains have greater mass than a valley, so the pull of gravity is stronger near mountains3http://celebrating200years.noaa.gov/foundations/gravity_surveys/welcome.html

What is a Gravity Survey?Accurately measure the height and flow of water in flat areas to make efficient use of water resources.Variations in gravity represent different densities beneath the surface.Variations may represent petroleum, natural gas, and various metals. Plan evacuation routes for low lying coastal areas.FEMA requires the use of survey data for flood control certificates.

4http://www.ngs.noaa.gov/PUBS_LIB/SocioEconomicBenefitsofCORSandGRAV-D.pdfImportance of Gravity Surveys4National Geodetic Vertical Datum of 1929 (NGVD 29)Originally known as the Sea Level Datum of 1929.Based on mean sea level (MSL) at 26 tidal gauges between the United States and Canada.21 in the U.S. and 5 in CanadaDefined by the observed heights at each tidal gauge and the elevations of all benchmark locations. MSL is not a constant. Impacted through wind, atmospheric pressure, water temperature and salinity. 5History of Gravity Surveyshttp://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdfNorth American Vertical Datum of 1988NAVD 88 was established in 1991 to replace NGVD 29. Data points collected through geodetic leveling and satellites. Data is very sparse.Errors in measurements as high as 2 meters. Majority of data collected in the 70s and 80s.

6History of Gravity Surveys

http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdfGravity for the Redefinition of the American Vertical Datum (GRAV-D)Created in 2007 to complete a thorough survey of the gravity field over the United States and its territories. NGS Federally Mandated project (80-373). Designed to replace existing gravity measurements from NAVD 88. Could see a potential economic benefit of $4.8 billion over fifteen years. Based primarily on flood plain mapping and avoidance costs for leveling. 7http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf78

Logistics DiagramNeed to add an aditional slide either before or after this to elaborate more on this process.

Need to talk about our data distributions at this point (at least introduce them to the audience so they can get a feel for where they are coming from) and talk about how they play a role in the process.8Percentages represent the annual goals for the GRAV-D project starting in FY2013. Currently, NOAA has been reaching their yearly targets of 5.6% per year. NOAA will need to increase yearly output to 8% to reach 2022 completion goal. 9FY13FY14FY15FY16FY17FY18FY19FY20FY21FY2228%36%44%52%60%68%76%84%92%100%Annual Target IdentificationWe need an exact percentage for out target instead of 5-6%.

It would also be helpful to show the yearly breakdown of past surveys instead of this estimate.91023%Project GapTargeted Completion Year - 20221011Historical Survey Data

Timeframe 2008 through 2012Important factorsWeather, Aircraft Maintenance, Aircraft Repair, Instrument Issues, and Personnel Days.

Need to add in the exact start date and the end date for this set of data. Probably sometime in 2008 (if anyone knows a month, good) and ending in 2012. Its easy for us to see, but we can add some text below with the specifics.

Also might want to point out any outliers. 11Survey Zones12

13Historical Data Distributions FactorsType of DistributionMean(days)Standard Deviation(days)Square ErrorAircraft MaintenanceBeta5.578.180.036Aircraft RepairBeta3.856.770.025Equipment RepairBeta2.143.800.035Weather DelayBeta4.984.000.021Personnel DayGamma3.061.840.005Need to rank these by their importance.

Also need to discuss the difference between maintenance and repair (one is scheduled, the other is not). Probably should talk about this at the cartoon. 13Theory - Anomalies in quality are variations outside the control limits of a process. W. Edwards Deming

To meet program target completion goals the variation of the delays in each process must be reduced.

Quality Variance 14Demings TheoryAgendaContext ReviewStakeholder AnalysisProblem & Need StatementsMethod of Analysis & SimulationRecommendation & Conclusion151516

Stakeholder Relationship DiagramDrive home the positives and the negatives. So, who helps the process.

Also talk through the loops instead of just randomly pointing. 16StakeholdersObjectivesTensionsNOAAResponsible for project management.Limited funding for implementing gravitational survey.Airplane ContractorsSupports gravitational survey objectives. Limitations on flight paths and aircraft use. Pilots and Support CrewsMain objective is to collect physical data. Limited amount of time and funding. Department of CommerceProvides funding for project.Requires annual completion targets. ResidentsReceive elevation measurements.Needs to give additional support to NOAAFEMAAcquire the survey data for flood control certificates.Limited on survey data completed for flood control certificates.17Planning StakeholdersAgain, Positives and Negatives. Also, dont just read off of this. 1718

Stakeholder Relationship DiagramStakeholdersObjectivesTensionsNOAAResponsible for project management.Limited funding for implementing gravitational survey.PilotsFlies the planes to allow the data to be collected.Limited hours that can be flown.Ground CrewsRepairs the planes.Limited amount of time and supplies or parts for repairs.SurveyorsCollects the physical datum.Limited amount of time and accuracy with equipment.19Execution StakeholdersAgendaContext ReviewStakeholder AnalysisProblem & Need StatementsMethod of Analysis & SimulationRecommendation & Conclusion2020NOAA has to reach 8% geographic area coverage annually. A plan to reduce variability within the gravitational survey is needed to maximize coverage within budget.Before Fiscal Year 202221Problem Statement21NOAA must complete the 8% annual quota but receives limited funding from the Department of Commerce.Making the gravity survey reduce variability will remove the tension with the Department of Commerce on NOAAs need for more financial backing by decreasing the time needed to complete a survey block. 22Need StatementLets see if we can combine the problem and need into one clear slide. 22AgendaContext ReviewStakeholder AnalysisProblem & Need StatementsMethod of Analysis & SimulationRecommendation & Conclusion2323Alternative 1Focus on Logistics ProcessImprove the execution of gravitational surveys and reduce variance in several variables which cause extra delays and unnecessary downtime.Alternative 2Acquire additional resourcesThe number of aircraft, equipment suites, and personnel limits the amount of surveys that can be completed annually.Alternative 3Combine Alternatives 1 & 2Maximizes the output, but is constrained by budget.24Design AlternativesThese are items that may need to be introduced in the context2425Value HierarchyGet rid of budget and make utility vs cost

Need to add in the utility chartRank each process based on difficulty to implement. 25Black Box Model

Explain each part of this (inputs and outputs), dont leave anything out26Used historical data to build a distribution for each process block.Assume process independence.Run the simulation for 10,000 replications and compare results.

Simulation Make sure to talk through the simulation and explain each part of it!!27Simulation Output (Base Case)Mean: 44.01 daysWorst case: 110.45 daysHistorical Data AnalysisMean: 41.63 daysWorst Survey: 76 daysWorst Values: 130 daysVerification Data ComparisonExplain where these come from2829Weather DelayAircraft MaintenanceAircraft RepairEquipment RepairPersonnel DayWeather Delay1-0.21-0.0660.490.17Aircraft Maintenance1-0.0055-0.160.62Aircraft Repair1-0.029-0.24Equipment Repair10.33Personnel Day1Verification Data CorrelationSymmetric correlation coefficientNegative relationship As the duration of one process increases, the duration of the corresponding process decreasesPositive relationship As the duration of one process increases, the duration of the corresponding process increasesMay need a new title

What should the takeaway be from this slide??? Need to add text and talk about why we did this and make the case that these are independent. 29Reduce the variance of each input variable by 5%, 10%, 15%, 20%, and 25%.Run 10,000 replications after each change.Calculate the days to completion.(10%) = ( - min) * 0.2 + min(50%) = (90%) = (max - ) * 0.8 + Analyze which variables have the biggest impact on the survey by subtracting the new value from the base case.Design of Experiment 30Data AnalysisInputsOutputsProcess Variance Reduction 10% to completion (days) 50% to completion (days) 90% to completion (days) Aircraft Maintenance 5%22.6743.9796.7910%22.6643.9296.3815%22.6443.8295.8020%22.9243.4492.8825%22.9843.3892.46Aircraft Repair 5%22.6643.9496.9510%22.6543.8896.7115%22.6443.8496.4620%22.6343.8096.1925%22.6243.7495.87Equipment Repair 5%22.7143.9996.9410%22.7443.9696.7015%22.7743.9396.4720%22.7943.8796.1625%22.9743.7494.15Weather Delay 5%22.6744.0197.2010%22.6744.0097.2415%22.6744.0197.2720%22.6744.0097.3025%22.6743.9797.31Personnel Day 5%23.1644.0196.7110%23.1144.0196.6615%23.0744.0196.6120%23.0444.0196.5725%23.0144.0196.53Lablel the inputs and outputs (up top)

Rank in terms of importance and circle the important parameters. 31ResultsDouble check weather

32Results33FactorsRank in VariabilityMax Delay Reduction (days)Mitigation StrategiesAircraft Maintenance14.70Additional maintenance personnel.Preventative maintenance.Aircraft Repair31.29Improved maintenance.Available spare parts.Equipment Repair23.01Back up equipment.Weather Delay5-0.15Weather analysis from regional historical data.Personnel Day40.63Schedule days off around other delays.Actually brief this slide and talk about it rather than just saying, here are results

Also rank 1 5, not 1,3,2

The preventative maintenance could be trouble, remember a,b,c,d checks for aircraft. I know them. 33Utility vs Cost34

AgendaContext ReviewStakeholder AnalysisProblem & Need StatementsMethod of Analysis & SimulationRecommendation & Conclusion3535RecommendationsAlternative 1 Focus on the logistics process of the surveys by allocating budget and resources towards improving parameters based on their rank in variability.This method has the least cost while still providing good way for survey execution based on the output value.Follow delay mitigation strategies to maximize the performance and data gathering of the survey.36Need to add quantitative data to this.

36ConclusionVariability reduction will reduce the time to conduct an average survey by 3 - 9 days based on 25% variability reduction.More surveys will be completed in 44 days or less.Save up to 47.4 days of survey time annually.Enough time to conduct another survey.Fewer days spent on survey results in less spending.37Mention where the 3 and 9 came from!

Need to explain more

Add chart of survey days on 25% variability reduction 37Questions?38EXTRA SLIDES/OLD SLIDES39Design to Improve the Productivity and Execution of Gravity Surveys

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Evan Demick, Kyle Luukkonen, Sadeep Nonis, Yuri Zhylenko

National Geodetic SurveyThe National Geodetic Survey (NGS) has a clearly defined mission statement: Define, maintain and provide access to the National Spatial Reference System (NSRS) to meet our nations economic, social, and environmental needs. (NOAA 2012)The National Geodetic Survey (NGS) is a government supported program that provides positioning information to the nation. NGS has several different projects currently underway (including GRAV-D and CORS) to aid in the measuring of elevation, longitude, latitude, and shoreline data. 41NAVD 88 was established in 1991 to replace the existing Sea Level Datum from 1929. Surface measurements were taken using a technique called leveling. 42http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf

Surveys were conducted over many years by numerous outside sources. Data is very sparse.Locations like Alaska have very few measurements due to terrain. A gap is also present along the coastlines. History of Gravity SurveysNeed to consider doing a history of vertical datums. 42Measurements are outdated and have been skewed due to crustal movements (last collected in the 70s and 80s). Many markings have been destroyed by regional development and poor maintenance. There is a transcontinental tilt from the SE to NW of the U.S. for short wavelength gravity measurements.Errors in measurements as high as 2 meters.

43http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdfNorth American Vertical Datum Importance of Gravity SurveysFEMA requires the use of survey data for flood control certificates. Floodplain maps also determine whether or not homes or buildings require flood insurance under the National Flood Insurance Program A FEMA run program with over $650 billion in insured assets. Mapping gravity can improve the accuracy of atomic clocks which are used in many electronic systems.Provide measurements that are geographically continuous rather than points based on physical monuments.

44http://www.ngs.noaa.gov/PUBS_LIB/SocioEconomicBenefitsofCORSandGRAV-D.pdfImportance of Gravity SurveysFloodplain maps are used to determine land use and building code requirements.Builders must have site plans and matching elevation data to help minimize any potential damage. Planning the development of new buildings and infrastructure. Variations in gravity represent different densities beneath the surface which can be used to detect petroleum, natural gas, and various metals.Mapping gravity can improve the accuracy of atomic clocks which are used in many electronic systems.Provide measurements that are geographically continuous rather than points based on physical monuments.

45Importance of Gravity SurveysRoad construction currently uses conventional geodetic leveling. Upgraded gravity surveys could replace conventional leveling for road works and save state and local municipalities as much as $300 billion per year. Replace leveling for sewage systems, water supply, and mass transit activities. Monitor changes over time in crustal motion to predict earthquakes and water flow.

46http://www.ngs.noaa.gov/PUBS_LIB/SocioEconomicBenefitsofCORSandGRAV-D.pdfGRAV-D ObjectivesRedefine the US vertical datum and replace geodetic leveling in large areas with GPS measurements and a gravimetric geoid model to determine orthometric heights. Redefine and improve the vertical component of NSRS. Provide a vertical datum that is more economical than traditional leveling.

47http://www.ngs.noaa.gov/PUBS_LIB/SocioEconomicBenefitsofCORSandGRAV-D.pdfEquipmentA test mass is first dropped and allowed to fall freely inside a vacuum chamber. The test mass will fall roughly 7 cm and the actual distance will be measured precisely using a laser interferometer and a rubidium standard atomic clock.As the test body falls, optical interference fringes are generated by the laser interferometer. These fringes are counted and timed with the atomic clock. The measurements of time and distance are then fitted to a parabolic trajectory that produces an accurate measure of the gravitational acceleration. The A10 provides measurements without the need for post-processing, and so reduces any additional overhead required to run the machine.

48Areas with Completed SurveysThe GRAV-D program has already covered several areas since starting in 2007. Eastern Alaska.Gulf of Mexico (focusing primarily on Louisiana and areas struck by Hurricane Katrina). The Great Lakes Region.California Coastline.49http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdfSurvey Area Layout50

http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdfSurvey Area Layout Design51

Google Earth Image Provided by NOAA - 2012Areas with Completed Surveys52

http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdfRemove

52Types of Wavelength Measurements 53http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf

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53Process for Completing Survey54

Wavelength MeasurementsMeasurements close to the planet capture short-wavelength and low-magnitude features. Measurements by plane capture intermediate-wavelength and midrange-magnitude features.Measurements by the satellites GOCE and GRACE capture long-wavelength and high-magnitude features.The satellites measure in 250x250 km data points and because of this the Satellite data cannot help fix the surface data because many of the surface surveys are smaller than 200x200 km.55http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdfGRAV DEllipsoidal heights are more common and much easier to find using GPS technology. Cannot be used to model water flow. Orthometric heights are related to water flow and can be used in floodplain mapping. Sometimes referred to as height above sea levelTo find orthometric heights, a model of the geoid must be created using measurements of the acceleration of gravity near the earths surface.

56http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdfCoast and Geodetic Survey ActPublic Law 80-373Objective is to provide a national coordinated spatial reference system. Will provide orientation, coordinated positions, and elevations at specific points for mapping, planning, and development. Extend the National Spatial Reference System into areas that are not currently covered to meet infrastructure needs. 57https://www.cfda.gov/?s=program&mode=form&tab=step1&id=40dbf9b68027de96a134c38f069efa3dRemove57EquipmentThe main pieces of technology in an equipment suite are a Gravimeter, Inertial Measurement Unit (IMU), and GPS Base stationA gravimeter is a device used to measure the vertical acceleration of gravity on the earths surface.The gravimeters run on the Turnkey Airborne Gravity System (TAGS).An IMU utilizes three accelerometers and three gyroscopes to measure the aircrafts current rotation and acceleration.A base station is a GPS receiver at a fixed location.It gives corrected position data for increased accuracy.58

Remove58Project ConstraintsNGS only owns two equipment suites, so only two field teams may run at one time$2.4 million budget per year for all survey operations (including aircraft, fuel, pilots, and NOAA personnel travel costs)Must use an airport with contract fuel when working on a government aircraftA standard block is 400 km by 500 km, which is approximately a 100 flight hour surveyBlocks must overlap by 30 - 40 km on the sides to make the survey data continuous

59Remove59Project ConstraintsGenerally northern areas in the summer, southern areas in the winterAvoid Eastern seaboard (especially SE) during Hurricane seasonAvoid Tornado Alley in Spring and Fall Go to Oregon/Washington area June-AugustGo to Western Alaska June - September

60Remove 60Contract Aircraft Availability61http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf

Remove61Constraints62

Remove62Distribution for Survey Days63

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63Distribution for Weather64

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64Project Constraints

65http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdfProject Constraints

66http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdfProcess Chart 67ProcessControllableTensions (affects air crews, contractors, and NOAAs projected time for completion)TransitnoTime variability affects total completion time for surveyPrepnoTime variability affects total completion time for surveySurveyyesData collection time restraints and accuracy of measurements Break-down DelaysyesUnplanned time delay

Weather DelaysnoUnplanned time delay, seasonal awareness can aid delay severityEquipment RemovalnoLow time variability calls for no variability reduction analysis

Planning Procedure Map out the survey blocks across all the required regionsSelect airports that maximize area coverage and meet the necessary constraintsAssign survey blocks to each aircraft for a specific yearCalculate the total cost by adding all the variablesFuel cost, hangar cost, hourly wages, hotel / meal cost, travel costCalculate cost risk for design comparison

68Need Statement (old)NOAA needs to complete the 8% annual quota but receives limited funding from the Department of Commerce.Making the gravity survey more efficient will remove the tension with the Department of Commerce on NOAAs need for more budget. Each Airplane Contractor needs to have their planes used evenly and fairly. The plan that is created needs to not rule out certain aircraft based on its constraints to minimize tension between each Airplane Contractor. NOAA needs the physical gravity datum but the pilots and support crews have a limited amount of time that they can work.NOAA needs to hire more pilots and/or implement a more efficient use of the pilots hours to maximize time in the air for gravity surveys. NOAA tries to prioritize each state based on State Government requests. NOAA needs to be willing to deviate from their set flight plans if in return a State Government can help fund the gravity survey.69Problem Statement (old)NOAA needs to complete 8% coverage of Continental U.S., Alaska, Hawaii, Puerto Rico, U.S. Virgin Islands, Guam, and American Samoa per year. Since 2008 NOAA has not reached their annual goal and have only covered around 5-6% per year of the U.S. and territories. A plan to reduce variability within NOAA's budget is needed to reach their 8% per year quota so they can complete the GRAV-D project by the Fiscal Year 2022.

70Survey Data71

Survey Data 72

Survey Data 73

73Cost Estimation74

Sample Cost Calculation75

Total Cost = (Total Fuel Cost + Total Per Diem Cost) 110%(The addition of 10% simulates additional knownbut difficult topre-estimatecosts, such as shipping, etc.).Distribution for Prep 76

Distribution for Transit77

Distribution for Aircraft Maintenance 78

Distribution for Instrument Issues79

Distribution for Personnel Day80

Design AlternativesAllocate current resources which would reduce the variance in major points of the project. Currently, NOAA operates with six aircraft, 4 teams, and two equipment packages. Determine major factors in reducing variability (backup aircraft or equipment maintenance). Add additional resources.To reduce variability add additional aircraft, equipment suites, or personnel.

81Design AlternativesAllocate current resources (focus on performance).Currently, NOAA operates with six aircraft, 4 teams, and two equipment suites. Determine major factors in reducing variability (backup aircraft or equipment maintenance).Add additional resources (focus on availability).To reduce variability add additional aircraft, equipment suites, or personnel. Add additional contract aircraft to increase aircraft availability. Additional resources and allocation (combination)

82Design AlternativesThe second alternative would be to add additional resources such as aircraft, equipment suites, or personnel as well as allocating them in an optimal manner. By having limited resources, NOAA is severely deterred in the number of surveys they can complete during a fiscal year. Additional assets will cost more money, but will speed up the process by allowing multiple surveys to be done at the same time and may be more beneficial in the long run of the project. 83Sensitivity Analysis Identify Parameter with biggest impact on time and cost.Identify the percent change in a parameter to 84Preliminary Recommendations Our simulation is similar to the real thing85Base Case

Aircraft Maintenance -5%





Aircraft Repair -5%

Aircraft Repair -10%




Equipment Repair -5%





Weather Delay -5%

Weather Delay -10%

Weather Delay -15%

Weather Delay -20%

Weather Delay -25%

Personnel Day -5%

Personnel Day -10%

Personnel Day -15%

Personnel Day -20%

Personnel Day -25%

Base Case vs Variance ReductionBase Case vs Variance ReductionWorks CitedGRAV-D Science Team (2011). "Gravity for the Redefinition of the American Vertical Datum (GRAV-D) Project, Airborne Gravity Data; Block AS01". Available 09/28/2012. Online at: http://www.ngs.noaa.gov/GRAV-D/data_as01.shtml GRAV-D Science Team (2011). "Block AS01 (Central South 01); GRAV-D Airborne Gravity Data User Manual." Theresa Diehl, ed. Version 1. Available 09/28/2012. Online at: http://www.ngs.noaa.gov/GRAV-D/data_as01.shtml GRAV-D Science Team (2011). "GRAV-D General Airborne Gravity Data User Manual." Theresa Diehl, ed. Version 1. Available 09/28/2012. Online at: http://www.ngs.noaa.gov/GRAV-D/data_as01.shtml LaCoste , Micro-g . "A-10 Gravimeter Users Manual." A-10 Outdoor Absolute Gravimeter. Micro-g LaCoste, July 2008. Web. 10 Oct 2012. ."IEEE-USA Consultants Fee Survey Report." Exality.com. IEEE-USA E-Books, 2011. Web. 14 Oct. 2012. .Special thanks to the project managers at NOAA for providing much of the information needed for the context and constraints.

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Assist Tool Preview This thing seems problematic. I think we get rid of it from the presentation and work on it on the side. They seem really confused by this and seem to think we are using it to make our recommendations with it. 115

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Design to Improve the Productivity and Execution of Gravity Surveys