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Alan Dragoo
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Maser Consulting


Alan R. Dragoo is a Licensed Surveyor in the State of Maryland, and was employed for 27 years by the Washington Suburban Sanitary Commission (WSSC) in Laurel, Maryland.  He was a Geodetic Project Manager in charge of high precision horizontal and vertical geodetic surveying projects using the Global Positioning System and classical methods in support of the WSSC Control Network, the Interagency GIS System and the deformation studies for 3 dams.  Alan also worked for Trimble Navigation for 8 years as a Technical Support Representative in support of sales for the Northeast U.S.  Alan also worked for Keystone Precision Instruments for 8 years as the Sales Manager for Land Survey products for Delaware, Maryland and Virginia.  He is currently employed by Maser Consulting at their Sterling, Virginia office as their Assistant Survey Department Manager.

Alan worked with the National Geodetic Survey to Survey the top of the Washington Monument.  Alan was Co-director for the completed survey on the top of the U.S. Capitol to determine its position and in the basement of the U.S. Capitol to locate the cornerstone set in 1792.  Alan is a member and Fellow of the National Society of Professional Surveyors; Past President for the American Association for Geodetic Surveying (AAGS), Past Editor for the “Geodetic Surveyor” a newsletter for AAGS, National Society of Professional Surveyors Director for the Maryland Society of Surveyors, and MSS Surveyor of The Year for 1996, Russell E. Lowman award and Life Time Achievement award in 2015.  Alan was also Director for the spring 1996 ASPRS/ACSM Baltimore Convention and Director for the spring 1998 ACSM Baltimore Convention.

Alan has authored and co-authored articles and papers for “Professional Surveyor” magazine, Surveying and Land Information System” a journal for the American Congress on Surveying and Mapping and society newsletters in the United States and Canada.  Alan has also presented numerous Technical Sessions and Workshops on matters related to geodetic surveying, State Plane Coordinates, Least Squares, Compatibility of GPS with Conventional Measurements, Trimble Business Center Software, and The Sources of Errors and Their Consequences for Conventional Surveying.

March 2016

 

Workshops
By
Alan R. Dragoo, PLS
Hamilton Virginia

adragoo@maserconsulting.com


Classes have been presented for the following:
Maryland Society of Surveyors
Virginia Association of Surveyors
American Congress on Surveying and Mapping
National Society of Professional Surveyors
International Federation of Surveyors
The 1994 Romanian delegation
Pennsylvania Society Land Surveyors
New Jersey Society of Professional Land Surveyors
West Virginia Association of Land Surveyors
Wisconsin Society of Land Surveyors
Delaware Association of Surveyors
New York State Association of Professional Land Surveyors
Trimble User Conference
US National Geodetic Survey
Various Bases for the US Air Force
US Navy
And Many More ….


Understanding Datums and Coordinate Systems so Your Data Will Fit Together
Horizontal coordinates NAD27,NAD83 (1986), (1991), (2011), (CORS) and WGS84 or old WSSC. Vertical elevations NGVD (1912), (1929), NAVD88. Understand how to recognize these datums and how to get from one to the other. Learn what software to use to change horizontal or vertical data from one datum to another. Learn the difference between a modeled solution and a conversion used to change data to a different datum and the large or small distortions you might expect to see.


1 to 2 Hours to fit available time
Control Surveys
Learn how to plan and execute the field work for a high precision horizontal and vertical control survey.


The following topics will be covered:
• The techniques that can be used and the accuracies, advantages and disadvantages you can expect for the following
 GPS Static
 OPUS Static
 OPUS Rapid Static
 Network RTK
 Conventional Traverse
 Conventional Leveling
• Learn how to get elevations that are twice as accurate from trig leveling.
• Where standards and specifications exist for these techniques they will also be discussed.
• We will also talk about how atmospheric conditions can affect traverse and level data with refraction and what actions can be taken to correct this.


4 Hours.
Understanding the Different Applications for GPS

GPS is used for many applications in today’s world from hunting and fishing to pushing dirt with a bulldozer or stakeout for construction. Learn about the different types of GPS, (recreational, mapping, and survey) applications and how they work. Learn the limitations of various types of GPS, their associated errors and how they should be used and not be used.


1 to 2 Hours to fit available time

Using the KeyNet GPS VRS System
The KeyNet GPS System will be explained. Principals and practices of using the KeyNet VRS System will be covered including setting up survey styles, dial profiles and Bluetooth connections for the TSC2 using Trimble Survey Controller software. Techniques will be presented and discussed to help you understand when you have problems with your data service or other problems. Accuracy issues will be discussed with techniques to minimize their impact. A VRS survey will be performed in the field. Exporting custom output reports will be presented. Trimble Geomatics Office and Trimble Business Center will be used to download the VRS RTK data and review the QA/QC qualities.


4 Hours

Using a KeyNet VRS Rover and Trimble S6 Robot for Integrated Surveying
Integrated surveying is the next new exciting technique for surveyors. The workshop will cover the following items.
1. Setting up an integrated survey style for Survey Controller in the TSC2 will be reviewed.
2. The KeyNet GPS system will be discussed.
3. GPS and Total Station accuracy issues will be discussed.
4. Field work will be performed using the integrated survey technique.
5. Field work will be downloaded to TBC for QA/QC.


4 Hours

Post Processed Network Design, Processing and Adjustment Using Trimble Business Center
Attendees will learn the most important part of post processed GPS, designing the network. Once this is done the data will be processed and the least squares adjustment of the network will be performed. This is a hands on class where the attendees will design several networks of increasing complexity which will be critiqued by the class. Previously observed data will be processed to derive the network that will be used to derive the final network adjustment.


8 Hours
Post Processed GPS Network Design
Attendees will learn the most important part of post processed GPS, how to design the network. The NGS document Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques will reviewed as it applies to network design and observing procedures. 4 or more networks will be designed and reviewed in class. Development of the GPS schedule will be presented. A systematic step by step process will be taught for the processing, QA/QC of the resulting data, and least squares adjustment.

 

5 Hours
RTK Surveying and OPUS - Using a GPS Base, Radio and GPS Rover
The basics of RTK Surveying will be presented. How to set up a survey style for simultaneously performing an RTK survey while collecting data for OPUS solutions and evaluating the quality of an OPUS Solution will be discussed. A survey will be performed to collect RTK, and data for an OPUS solution will be collected and downloaded to Trimble Business Center. Troubleshooting radio issues will also be discussed in the field exercise. A OPUS solution will be obtained and the RTK survey data moved to coincide with the OPUS solution.

 

4 Hours
Controlling Errors in Conventional Survey Measurements for GPS Compatibility
Errors in conventional measurements, especially angles and distances accumulate so quickly and unexpectedly for some surveyors that they are left wondering; “why those GPS positions don’t check the survey measurements”. The errors in GPS vectors and conventional measurements propagate differently.
The workshop will cover:
1. Identifying and quantifying random errors.
2. Identifying and quantifying systematic errors and correcting for them.
3. Identifying equipment calibration and adjustment errors and correcting for them.
4. The use of proper observing techniques for error elimination.
5. The use of proper adjustment techniques for random error distribution and evaluation.
Through the application of the knowledge gained in this workshop attendees will understand and appreciate the complete consistency and compatibility of GPS and conventional measurements.

 

4 Hour presentation time
Controlling Errors in Conventional Survey Measurements
Accumulated systematic errors in survey measurements are difficult to identify and eliminate unless they are large. Errors in conventional measurements, especially angles and distances accumulate so quickly and unexpectedly for some surveyors that when they run linear connecting traverses they don’t understand why they suddenly have error problems they never had before.
The workshop will cover:
1. Identifying and quantifying random errors.
2. Error propagation.
3. Identifying and quantifying systematic errors and correcting for them.
4. Identifying equipment calibration and adjustment errors and correcting for them.
5. The use of proper observing techniques for error elimination.
6. The use of proper adjustment techniques for random error distribution and evaluation.
Through the application of the knowledge gained in this workshop attendees will understand that it is very little effort to have measurements with much greater accuracy and therefore not adjust them into your project only to have them come back to haunt you later.

 

4 Hour presentation time
Practical Least Squares Adjustments for Survey Measurements
A true Least Squares Adjustments is where all measurements and known values are considered and adjusted so that the differences between any field measurement and the adjusted value is at a minimum is always a better adjustment. Surveyors intuitively use Least Squares principals for measurement adjustment.
The workshop will cover:
1. Understanding the concept of how Least Squares works.
2. Understanding the concepts of statistical terms used in Least Squares Adjustments.
3. Understanding instrument error sources and magnitude for use in Least Squares.
4. The practical application of redundancy to a survey control project.
This workshop will present the knowledge necessary to understand the concepts of Least Squares adjustments, leaving the math to be preformed by the computers. Attendees will learn what data needs to be available to do a Least Squares adjustment and understand the results of the completed adjustment. Control survey error detection and adjustment strategy will also be discussed.

 

4 Hour presentation time
Using Trimble Business Center to perform a Least Squares adjustment of your data when your project has both GPS and conventional survey data
The KeyNet VRS system will be used to determine the positions of 6 stations. Proper techniques for checking or adjusting conventional equipment will be reviewed. A traverse loop will be run through 3 of these stations with the other 3 used as azimuth stations. The data will be brought into TBC where the data will be QA/QCed and analyzed and a Least Squares adjustment will be performed to develop the final project control values.

 

8 Hours
Practical Least Squares Adjustments for Survey Measurements with Lab
A true Least Squares Adjustments is where all measurements and known values are considered and adjusted so that the differences between any field measurement and the adjusted value is at a minimum is always a better adjustment. Surveyors intuitively use practical Least Squares principals for measurement adjustment.
The workshop will cover:
1. Understanding the concept of how Least Squares works.
2. Understanding the concepts of statistical terms used in Least Squares Adjustments.
3. Understanding instrument error sources and magnitude for use in Least Squares.
4. The practical application of redundancy to a survey control project.
This workshop will present the knowledge necessary to understand the concepts of Least Squares adjustments, leaving the math to be preformed by the computers. Attendees will learn what data needs to be available to do a Least Squares adjustment and understand the results of the completed adjustment. Control survey error detection and adjustment strategy will also be discussed. The last 4 hours of this class will be devoted to the actual hands on process of using a leading true Least Squares adjustment program where data will be keyed in, analyzed and adjusted. Each person will have access to a computer with software to use.

 

8 Hour presentation time
Computations Using the NAD83 State Plane Coordinate System.
Correcting your survey measurements for the size and shape of the earth instead of accumulating these errors in your traverse can triple or quadruple the accuracy of your survey control.
The workshop will cover:
1. Understanding the concept of projections
2. Understanding the concepts of the State Plane Coordinate System.
3. The calculation of the grid & elevation factor.
4. Understanding NGS Data Sheets.
5. The computation of NAD83 State Plane Coordinates.
This workshop will be a hands-on interactive workshop where attendees will be expected to bring a survey quality calculator which will be used to calculate the State Plane Coordinates for several survey traverses in class.

 

4 Hour presentation time.
Understanding Subsidence In the Gulf Coast States and Mid-Atlantic Ares and How to Deal With It in Your Survey Measurements.
Since our nationwide leveling is based on NGS work that is 37 years old 0.005 ft change a year will equal close to 0.20 feet. Some places are changing much more than this. Understanding subsidence, how it affects you survey measurements and how you will deal with it before you encounter it will save you much time money and aggravation for your survey project. Learn about the research past, present and future to determine and quantify this movement. We will also discuss the practical implications to surveying. Because subsidence and Sea Level Rise both have a compounding effect on water related to the shore line the magnitude of Sea Level Rise is addressed. In the past the National Geodetic Survey used campaign precise leveling to detect crustal movement. Since this type of leveling has not been accomplished by NGS since the late 1970’s we need to now use the National CORS Network to help detect crustal movement in our geographic area. To do this we need to understand the errors associated with Orthometric heights. Different strategies will be discussed to detect and to deal with crustal movement problem

 

2 Hour presentation time.
Using TBC to Bluebook Data for Airport Surveys or National Geodetic Survey (NGS) Height Mod Projects.
Do you think Bluebooking data for submission and publication by the NGS is DEAD. Anyone that has gone through this process may wish it was but Height Mod Projects conducted by states and PACS and SACS set to control Airport Survey require the data to be Bluebooked.
This class will cover how static GPS projects are Bluebooked for submission to the National Geodetic Survey (NGS) for inclusion in the U.S. National Spatial Reference System. Topics covered will be:
• Proper network design.
• Helpful information from NGS.
• The use of the data fields in TBC.
• Creation of the NGS GFILE.
• Creation of the NGS BFILE.
• Creation of the NGS AFILE.
• Creation of the NGS DFILE.
• Using TBC for the validation checks to meet the 2 or 5 cm rejection limit.
• Using NGS Adjust for the final adjustment.

 

 

NSPS strives to establish and further common interests, objectives, and political effort that would help bind the surveying profession into a unified body in the United States.

Governance: The National Society of Professional Surveyors Inc. is governed by a Board of Directors. The NSPS Board of Directors meets twice per year.   NSPS has working agreements with state surveying organizations which are represented on the NSPS Board of Directors, and with the NSPS Foundation, Inc. 


Contact Us

5119 Pegasus Court
Suite Q
Frederick, MD 21704
Phone: 240-439-4615
Fax: 240-439-4952

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