Starodub’s APE-2 system

 

The second-generation advanced pavement evaluation system is now available from Starodub, Inc. The first prototype was developed and tested during the past two years. The APE-2 system is a turn-key solution for bridge decks, utility detection, and pavement.

 

Research and Development History

 

The step-frequency ground-penetrating-radar (SF-GPR) technology was identified in 2005 by Starodub, Inc. Since then, under the support of FHWA, four generations of hardware were utilized to address the limitations of traditional impulse GPR solutions.

 

Table 1. Recapitulation of Starodub’s advances in SF-GPR from 2005 to 2014

 

 

 

In table 1, the incremental progress achieved in both hardware by the manufacturer and development of applications by Starodub, Inc. shows a technical foundation in 2014 that supported a development effort towards end-products for highway applications.

 

For additional information, please contact us at: 

SFGPR@starodub.com

 

Components of APE-2 System

 

Hardware

Turn-key system for data collection with or without maintenance of traffic (MOT). Safety is the first concern, and Productivity the second. Figure 1 is a picture of our first prototype of the APE-2 system developed in 2014.

 

 

Figure 1. APE-2 Prototype System

 

Our hardware layout and standard operating procedures maximize safety of the operators, the ease of deployment with computer-aided data collection, the quality of the data, and the protection of the equipment.

 

The pre- and post- procedures support the QC/QA requirements.

 

Software

 

Computer-Assisted Data Collection using GIS tools and real-time feedback about registration of data and completeness of data. Figures 2 through 4 show three of the stages of the feedback provided by our software during data collection.

 

Figure 2. Real-Time Feedback during data collection – Approaching the site.

 

Figure 3. Real-Time Feedback during data collection – During Data-Acquisition.

 

 

Figure 4. Real-Time Feedback during data collection – After Data-Acquisition.

 

Automated Data Processing Pipeline using our patented methods and protocols. Figure 5 is a flowgraph of the standard modules included in the analysis for bridge decks. Other specialized modules are available for utility detection and pavements.

 

 

Figure 5. Analysis Pipeline for Bridge Decks

 

Technical Advantages of APE-2 System

 

SF-GPR provides multiple advantages over traditional impulse GPR. Its three primary advantages are:

1. A greater bandwidth (150MHz to 3GHz) that spans over at a combination of the bandwidths of at least seven impulse antennas. For impulse antennas, the bandwidth is defined in terms of center frequency and the frequency range of its corresponding octave or third octave. Note that the power level is maximum at the center frequency and decrease rapidly as shown in the graphical representation in figure 6.

 

 

Figure 6. Comparison of SF-GPR frequency bandwidth and those of four individual Impulse GPR antennas.

 

2. An array configuration sufficiently compact to support advanced protocols that can be used to calibrate results and no longer require cores to be taken at the sites.
3. An ability to apply notches on the bandwidth to the minimum number of frequency steps which also allows the ability to remove the adverse effect of external interference at the specific frequency steps without impacting the other frequency steps – an ability not possible if impulse antennas are used. Typically, more than 90% of the bandwidth is acceptable. For impulse GPR, the proximity of the external interference both to the site and to the center frequency of the bandwidth of the transmitter impulse prevent the measurement of acceptable data.

 

Starodub’s algorithms have been developed with the technical foundation accumulated over a period of ten years. The following advantages were noted by the first users of our products:

1. Quality Control: our analysis pipeline is designed to review and organize a large number of raw SF-GPR data files into projects. At the same time, the data is reviewed for multiple items: completeness, quality, registration, consistency
2. Automation: Once the individual projects are established, the data elements are produced, the visualization files prepared, and statistics tabulated.
3. A report template is defined in terms of data elements, visualization, tables, plotting scales and formats.
4. Self-calibration of GPR algorithms: Traditional GPR solutions require the use of cores to convert time sample to depth. Our solution is based on our solutions patented in 2012, proposed in 2006.

 

Example: Comparison of Two Bridge Deck Structures

 

Concrete Bridge Deck with or without asphalt overlay

 

High-resolution 3D sampling with state-of-the-art ground penetrating radar at speed up to 45mph, 80% sampling minimum 

 

Safe, efficient, verified, validated, and complete solution successfully deployed: Data collection, calibration, quality control, automated processing, visualization, tabulated statistics, interpretation, ranking. No interpolation, No extrapolation.

 

 

Standard data elements: Surface elevation, concrete surface condition, cover-depth, Top-rebar condition, deck thickness

 

Figures 7 and 8 are plots of standard data elements for two different structures to illustrate some of the visualization produced by the analysis pipeline. It is important to realize that NO INTERPOLATION and NO EXTRAPOLATION is used. Each data set from each data collection is analyzed independently and results plotted together. There is no “consistency” adjustment. There is no empirical correction applied between data sets. Figure 9 is a set of histograms for the data elements presented in figures 7 and 8. Note that the distributions vary from structure to structure.

 

Figure 7. Data Elements for First Structure

 

 

Figure 8. Data Elements for Second Structure

Figure 9. Histograms for Standard Data Elements

 

 

For additional information, please contact us at:

SFGPR@starodub.com