Slide 1

Design to Improve the Productivity and Execution of Gravity Surveys Evan Demick Kyle Luukkonen Sadeep Nonis Yuri Zhylenko Sponsor: Sandra Preaux - NOAA Slide 2 Agenda Context Review Stakeholder Analysis Problem & Need Statements Method of Analysis & Simulation Recommendation & Conclusion 2 Slide 3 Collection 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 mountains 3 http://celebrating200years.noaa.gov/foundations/gravity_surveys/welcome.html What is a Gravity Survey? Slide 4 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. 4 http://www.ngs.noaa.gov/PUBS_LIB/SocioEconomicBenefitsofCORSandGRAV-D.pdf Importance of Gravity Surveys Slide 5 National 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 Canada Defined 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. 5 History of Gravity Surveys http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf Slide 6 North American Vertical Datum of 1988 NAVD 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. 6 History of Gravity Surveys http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf Slide 7 Gravity 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. 7 http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf Slide 8 8 Logistics Diagram Slide 9 Percentages 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. 9 FY13FY14FY15FY16FY17FY18FY19FY20FY21FY22 28%36%44%52%60%68%76%84%92%100% Annual Target Identification Slide 10 10 23% Project Gap Targeted Completion Year - 2022 Slide 11 11 Historical Survey Data Timeframe 2008 through 2012 Important factors Weather, Aircraft Maintenance, Aircraft Repair, Instrument Issues, and Personnel Days. Slide 12 Survey Zones 12 Slide 13 13 Historical Data Distributions Factors Type of Distribution Mean (days) Standard Deviation (days) Square Error Aircraft Maintenance Beta5.578.180.036 Aircraft RepairBeta3.856.770.025 Equipment Repair Beta2.143.800.035 Weather DelayBeta4.984.000.021 Personnel DayGamma3.061.840.005 Slide 14 Theory - 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 14 Demings Theory Slide 15 Agenda Context Review Stakeholder Analysis Problem & Need Statements Method of Analysis & Simulation Recommendation & Conclusion 15 Slide 16 16 Stakeholder Relationship Diagram Slide 17 StakeholdersObjectivesTensions NOAAResponsible for project management. Limited funding for implementing gravitational survey. Airplane ContractorsSupports gravitational survey objectives. Limitations on flight paths and aircraft use. Pilots and Support Crews Main objective is to collect physical data. Limited amount of time and funding. Department of Commerce Provides funding for project. Requires annual completion targets. ResidentsReceive elevation measurements. Needs to give additional support to NOAA FEMAAcquire the survey data for flood control certificates. Limited on survey data completed for flood control certificates. 17 Planning Stakeholders Slide 18 18 Stakeholder Relationship Diagram Slide 19 StakeholdersObjectivesTensions NOAAResponsible 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. 19 Execution Stakeholders Slide 20 Agenda Context Review Stakeholder Analysis Problem & Need Statements Method of Analysis & Simulation Recommendation & Conclusion 20 Slide 21 NOAA 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 2022 21 Problem Statement Slide 22 NOAA 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. 22 Need Statement Slide 23 Agenda Context Review Stakeholder Analysis Problem & Need Statements Method of Analysis & Simulation Recommendation & Conclusion 23 Slide 24 Alternative 1 Focus on Logistics Process Improve the execution of gravitational surveys and reduce variance in several variables which cause extra delays and unnecessary downtime. Alternative 2 Acquire additional resources The number of aircraft, equipment suites, and personnel limits the amount of surveys that can be completed annually. Alternative 3 Combine Alternatives 1 & 2 Maximizes the output, but is constrained by budget. 24 Design Alternatives Slide 25 25 US Gravity Survey Availability (0.35) Area Coverage (0.43) Time (0.22) Value Hierarchy Slide 26 Black Box Model Slide 27 Used historical data to build a distribution for each process block. Assume process independence. Run the simulation for 10,000 replications and compare results. Simulation Slide 28 Simulation Output (Base Case) Mean: 44.01 days Worst case: 110.45 days Historical Data Analysis Mean: 41.63 days Worst Survey: 76 days Worst Values: 130 days Verification Data Comparison Slide 29 29 Weather Delay Aircraft Maintenance Aircraft Repair Equipment Repair Personnel Day Weather Delay 1-0.21-0.0660.490.17 Aircraft Maintenance 1-0.0055-0.160.62 Aircraft Repair 1-0.029-0.24 Equipment Repair 10.33 Personnel Day 1 Verification Data Correlation Symmetric correlation coefficient Negative relationship As the duration of one process increases, the duration of the corresponding process decreases Positive relationship As the duration of one process increases, the duration of the corresponding process increases Slide 30 Reduce 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 Slide 31 Data Analysis InputsOutputs ProcessVariance Reduction10% to completion (days)50% to completion (days)90% to completion (days) Aircraft Maintenance 5% 22.6743.9796.79 10% 22.6643.9296.38 15% 22.6443.8295.80 20% 22.9243.4492.88 25% 22.9843.3892.46 Aircraft Repair 5% 22.6643.9496.95 10% 22.6543.8896.71 15% 22.6443.8496.46 20% 22.6343.8096.19 25% 22.6243.7495.87 Equipment Repair 5% 22.7143.9996.94 10% 22.7443.9696.70 15% 22.7743.9396.47 20% 22.7943.8796.16 25% 22.9743.7494.15 Weather Delay 5% 22.6744.0197.20 10% 22.6744.0097.24 15% 22.6744.0197.27 20% 22.6744.0097.30 25% 22.6743.9797.31 Personnel Day 5% 23.1644.0196.71 10% 23.1144.0196.66 15% 23.0744.0196.61 20% 23.0444.0196.57 25% 23.0144.0196.53 Slide 32 Results Slide 33 33 Factors Rank in Variability Max Delay Reduction (days) Mitigation Strategies Aircraft Maintenance 1 4.70 Additional maintenance personnel. Preventative maintenance. Aircraft Repair3 1.29 Improved maintenance. Available spare parts. Equipment Repair 2 3.01 Back up equipment. Weather Delay5 -0.15 Weather analysis from regional historical data. Personnel Day4 0.63 Schedule days off around other delays. Slide 34 Utility vs Cost 34 Slide 35 Agenda Context Review Stakeholder Analysis Problem & Need Statements Method of Analysis & Simulation Recommendation & Conclusion 35 Slide 36 Recommendations Alternative 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. 36 Slide 37 Conclusion Variability 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. 37 Slide 38 38 Slide 39 EXTRA SLIDES/OLD SLIDES 39 Slide 40 Design to Improve the Productivity and Execution of Gravity Surveys 40 Evan Demick, Kyle Luukkonen, Sadeep Nonis, Yuri Zhylenko Slide 41 National Geodetic Survey The 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. 41 Slide 42 NAVD 88 was established in 1991 to replace the existing Sea Level Datum from 1929. Surface measurements were taken using a technique called leveling. 42 http://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 Surveys Slide 43 Measurements 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. 43 http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf North American Vertical Datum Slide 44 Importance of Gravity Surveys FEMA 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. 44 http://www.ngs.noaa.gov/PUBS_LIB/SocioEconomicBenefitsofCORSandGRAV-D.pdf Slide 45 Importance of Gravity Surveys Floodplain 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. 45 Slide 46 Importance of Gravity Surveys Road 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. 46 http://www.ngs.noaa.gov/PUBS_LIB/SocioEconomicBenefitsofCORSandGRAV-D.pdf Slide 47 GRAV-D Objectives Redefine 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. 47 http://www.ngs.noaa.gov/PUBS_LIB/SocioEconomicBenefitsofCORSandGRAV-D.pdf Slide 48 Equipment A 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. 48 Slide 49 Areas with Completed Surveys The 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. 49 http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf Slide 50 Survey Area Layout 50 http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf Slide 51 Survey Area Layout Design 51 Google Earth Image Provided by NOAA - 2012 Slide 52 Areas with Completed Surveys 52 http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf Slide 53 Types of Wavelength Measurements 53 http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf Slide 54 Process for Completing Survey 54 Slide 55 Wavelength Measurements Measurements 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. 55 http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf Slide 56 GRAV D Ellipsoidal 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 level To find orthometric heights, a model of the geoid must be created using measurements of the acceleration of gravity near the earths surface. 56 http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf Slide 57 Coast and Geodetic Survey Act Public Law 80-373 Objective 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. 57 https://www.cfda.gov/?s=program&mode=form&tab=step1&id=40dbf9b68027de96a134c38f069efa3d Slide 58 Equipment The main pieces of technology in an equipment suite are a Gravimeter, Inertial Measurement Unit (IMU), and GPS Base station A 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 Slide 59 Project Constraints NGS 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 aircraft A standard block is 400 km by 500 km, which is approximately a 100 flight hour survey Blocks must overlap by 30 - 40 km on the sides to make the survey data continuous 59 Slide 60 Project Constraints Generally northern areas in the summer, southern areas in the winter Avoid Eastern seaboard (especially SE) during Hurricane season Avoid Tornado Alley in Spring and Fall Go to Oregon/Washington area June-August Go to Western Alaska June - September 60 Slide 61 Contract Aircraft Availability 61 http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf Slide 62 Constraints 62 Slide 63 Distribution for Survey Days 63 Slide 64 Distribution for Weather 64 Slide 65 Project Constraints 65 http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf Slide 66 Project Constraints 66 http://geodesy.noaa.gov/GRAV-D/pubs/GRAV-D_v2007_12_19.pdf Slide 67 Process Chart 67 ProcessControllableTensions (affects air crews, contractors, and NOAAs projected time for completion) TransitnoTime variability affects total completion time for survey PrepnoTime variability affects total completion time for survey SurveyyesData collection time restraints and accuracy of measurements Break-down DelaysyesUnplanned time delay Weather DelaysnoUnplanned time delay, seasonal awareness can aid delay severity Equipment Removal noLow time variability calls for no variability reduction analysis Slide 68 Planning Procedure Map out the survey blocks across all the required regions Select airports that maximize area coverage and meet the necessary constraints Assign survey blocks to each aircraft for a specific year Calculate the total cost by adding all the variables Fuel cost, hangar cost, hourly wages, hotel / meal cost, travel cost Calculate cost risk for design comparison 68 Slide 69 Need 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. 69 Slide 70 Problem 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. 70 Slide 71 Survey Data 71 Slide 72 Survey Data 72 Slide 73 Survey Data 73 Slide 74 Cost Estimation 74 Slide 75 Sample Cost Calculation 75 Total Cost = (Total Fuel Cost + Total Per Diem Cost) 110% (The addition of 10% simulates additional knownbut difficult to pre-estimatecosts, such as shipping, etc.). Slide 76 Distribution for Prep 76 Slide 77 Distribution for Transit 77 Slide 78 Distribution for Aircraft Maintenance 78 Slide 79 Distribution for Instrument Issues 79 Slide 80 Distribution for Personnel Day 80 Slide 81 Design Alternatives Allocate 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. 81 Slide 82 Design Alternatives Allocate 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) 82 Slide 83 Design Alternatives The 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. 83 Slide 84 Sensitivity Analysis Identify Parameter with biggest impact on time and cost. Identify the percent change in a parameter to 84 Slide 85 Preliminary Recommendations Our simulation is similar to the real thing 85 Slide 86 Base Case Slide 87 Aircraft Maintenance -5% Slide 88 Aircraft Maintenance -10% Slide 89 Aircraft Maintenance -15% Slide 90 Aircraft Maintenance -20% Slide 91 Aircraft Maintenance -25% Slide 92 Aircraft Repair -5% Slide 93 Aircraft Repair -10% Slide 94 Aircraft Repair -15% Slide 95 Aircraft Repair -20% Slide 96 Aircraft Repair -25% Slide 97 Equipment Repair -5% Slide 98 Equipment Repair -10% Slide 99 Equipment Repair -15% Slide 100 Equipment Repair -20% Slide 101 Equipment Repair -25% Slide 102 Weather Delay -5% Slide 103 Weather Delay -10% Slide 104 Weather Delay -15% Slide 105 Weather Delay -20% Slide 106 Weather Delay -25% Slide 107 Personnel Day -5% Slide 108 Personnel Day -10% Slide 109 Personnel Day -15% Slide 110 Personnel Day -20% Slide 111 Personnel Day -25% Slide 112 Base Case vs Variance Reduction Slide 113 Slide 114 Works Cited GRAV-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.shtmlhttp://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.shtmlhttp://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 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. 114 Slide 115 Assist Tool Preview