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TECHNICAL REPORT STANDARD PAGE 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. FHWA/LA.09/459 4. Title and Subtitle 5. Report Date Reference Measurements of Pavement Management August 2009 System Roadway Elevations 6. Performing Organization Code LTRC Project Number: 09-2GT State Project Number: 737-99-0954 7. Author(s) 8. Performing Organization Report No. J. Anthony Cavell, PLS, CFedS Roy Dokka, Ph.D. 9. Performing Organization Name and Address 10. Work Unit No. Center for Geoinformatics Department of Civil and Environmental Engineering 11. Contract or Grant No. Louisiana State University Baton Rouge, LA 70803 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Louisiana Department of Transportation and Development Final Report P.O. Box 94245 August 2008-June 2009 Baton Rouge, LA 70804-9245 14. Sponsoring Agency Code 15. Supplementary Notes Conducted in Cooperation with the U.S. Department of Transportation, Federal Highway Administration 16. Abstract New, more efficient methods of measuring road surfaces, including using moving vehicles, are being developed and deployed. Testing the veracity of such data presents its own problems. Busy, heavily traveled highways do not lend themselves to easy occupation for careful measurements by conventional means. The advent of GULFNet by the Louisiana State University (LSU) Center for Geoinformatics (C4G) provides the ability to get highly precise, accurate positions anywhere within the state tied to the National Spatial Reference System (NSRS), which enabled the establishment of benchmark sections of roadway against which the performance of new methods may be tested. The LSU C4G with the cooperation of Louisiana Department of Transportation (LADOTD) personnel accessed and measured the elevations and locations of points, quickly and safely, along test sections of highways in each LADOTD district. The precisions of the measurements, as reported by the Real-Time Kinematic (RTK) engine, averaged better than 3 cm at three standard deviations (3σ). Recommendations are made for using the measurements at the sites for testing the Moving Vehicle Rapid Mapping (MVRM) systems to assess the precisions reasonably to be expected by these systems under a variety of circumstances. 17. Key Words 18. Distribution Statement Unrestricted. This document is available through the National Technical Information Service, Springfield, VA 21161. 19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price 182 Project Review Committee Each research project will have an advisory committee appointed by the LTRC Director. The Project Review Committee is responsible for assisting the LTRC Administrator or Manager in the development of acceptable research problem statements, requests for proposals, review of research proposals, oversight of approved research projects, and implementation of findings. LTRC appreciates the dedication of the following Project Review Committee Members in guiding this research study to fruition. LTRC Manager Gavin Gautreau, P.E. Senior Geotechnical Research Manager Members Leslie Mix, P.E. James Lee Ashley Horne Directorate Implementation Sponsor William Temple 2 Reference Measurements of Pavement Management System Roadway Elevations by J. Anthony Cavell, PLS, CFedS Associate Director Roy Dokka, Ph.D. Executive Director Center for Geoinformatics South Stadium Drive Baton Rouge, LA 70803 LTRC Project No. 09-2GT State Project No. 737-99-0954 conducted for Louisiana Department of Transportation and Development Louisiana Transportation Research Center The contents of this report reflect the views of the author/principal investigator who is responsible for the facts and the accuracy of the data presented herein. The contents of do not necessarily reflect the views or policies of the Louisiana Department of Transportation and Development or the Louisiana Transportation Research Center. This report does not constitute a standard, specification, or regulation. August 2009 ABSTRACT New, more efficient methods of measuring road surfaces, including using moving vehicles, are being developed and deployed. Testing the veracity of such data presents its own problems. Busy, heavily traveled highways do not lend themselves to easy occupation for careful measurements by conventional means. The advent of GULFNet by the Louisiana State University (LSU) Center for Geoinformatics (C4G) provides the ability to get highly precise, accurate positions anywhere within the state tied to the National Spatial Reference System (NSRS), which enabled the establishment of benchmark sections of roadway against which the performance of new methods may be tested. The LSU C4G with the cooperation of Louisiana Department of Transportation (LADOTD) personnel accessed and measured the elevations and locations of points, quickly and safely, along test sections of highways in each LADOTD district. The precisions of the measurements, as reported by the Real-Time Kinematic (RTK) engine, averaged better than 3 cm at three standard deviations (3σ). Recommendations are made for using the measurements at the sites for testing the Moving Vehicle Rapid Mapping (MVRM) systems to assess the precisions reasonably to be expected by these systems under a variety of circumstances. iii ACKNOWLEDGMENTS As with anything of significance, this project could not be accomplished without the support and assistance of many. Some who deserve significant acknowledgement include Roy K. Dokka, Ph.D., director of LSU C4G and principal investigator (P.I.) of this project. Randy Osborne also with LSU C4G kept the computing and network systems working as needed, without which the GULFNet would not work. J. Ashley Horne with LADOTD chose the test sites, coordinated the arrangements with local districts, and kept things on tract. Said Ismail, P.E., management systems engineer of LADOTD, was alert to request the recommendations for applying the results. Delicia Justice of LADOTD was an able assistant and lookout while in the field making the measurements. Gavin Gautreau, P.E., senior geotechnical research engineer with LTRC, interpreted the paperwork and kept the lines of communication open for those involved. Leslie Mix, P.E., and James Lee of LADOTD along with other members of the project committee helped form the scope of the project. Last but certainly not least, the leaders and safety teams at each district earned our thanks for their expertise and diligence keeping the author and others involved safe at each of the chosen sites. v IMPLEMENTATION STATEMENT The first step in implementing the recommendations of this report is to require any MVRM vehicle that is going to survey the roads of Louisiana for LADOTD to be driven over the test site or test sites near to where its intended use is located following the protocol below: A. Ideal State. MVRM operators should drive their vehicle over the test site with the Global Navigation Satellite System (GNSS) RTK and Inertial Navigation working as designed and record the results. These results will be compared to the benchmark data to ascertain the expected deviation from the system under optimal conditions and may help set expectations of the highest precisions attainable with the particular system. Repeating the passes will increase the confidence in the prediction. B. Brief Inertial State. MVRM operators should drive their vehicle over the test site with GNSS RTK blocked just before entering the test area and Inertial Navigation working as designed. These results will be compared to the benchmark data to ascertain the expected deviation from the system when the normal GNSS signal blockages occur. Repeating the passes will likely increase the confidence in the prediction. C. Extended Inertial State. MVRM operators should drive their vehicle over the test site with GNSS RTK blocked for extended time and Inertial Navigation working as designed. These results will be compared to the benchmark data to ascertain the expected deviation from the system when the longer than normal GNSS signal blockages occur. Repeating the passes will likely increase the confidence in the prediction. D. Post-Processing State. MVRM operators should drive their vehicle over the test site with GNSS RTK blocked for extended time and Inertial Navigation working as designed. Results will be post-processed to generate positions. These results will be compared to the benchmark data to ascertain the expected deviation from the system when using post-processing. Repeating the passes will likely increase the confidence in the prediction. Some passes should be considered with the GNSS signal blocked as in B and C. The comparison of the results on a test site while re-creating the conditions commonly expected to be experienced in the field will allow the prediction of the MCRM system performance. vii TABLE OF CONTENTS ABSTRACT ............................................................................................................................. iii ACKNOWLEDGMENTS .........................................................................................................v IMPLEMENTATION STATEMENT .................................................................................... vii TABLE OF CONTENTS ......................................................................................................... ix LIST OF TABLES ................................................................................................................... xi LIST OF FIGURES