Innovating the NDE Data Acquisition Process

From the creation of the first simple stone tools to the invention of the world wide web, technological innovation has been the undercurrent that has carried the human species from our primitive survivalist ways to our present-day complexity of modern conveniences. We innovate from necessity, competition, or from a desire for an improved quality of life. Innovation has been and remains key to our survival and proliferation.

In business, it is no different and innovation has been a mainstay at Structural Integrity and part of our core values since our inception in 1983. We are constantly developing and applying innovative practices and technologiesto meet our clients’ toughest challenges and to provide best-in-value solutions. In this spirit, we are excited to announce one of our most recent innovations, LATITUDETM.


LATITUDE is a non-mechanized position and orientation encoding technology designed for use with nondestructive evaluation (NDE) equipment. Simply stated, LATITUDE enables an operator to manipulate a probe by hand while maintaining a digital record of the position and orientation of the probe at all times. For many applications, LATITUDE can be thought of as a fast and compact alternative to cumbersome and complicated automated inspection equipment.

To replace all the tracks, motors, motion controllers, probe carts, and other equipment used for traditional automated inspections, the LATITUDE system uses air-borne ultrasound to track the position of a transmitting probe relative to a set or array, of stationary receiver sensors. In this way, the LATITUDE transmitting probe can be attached to any of a variety of NDE probes and the absolute position of the NDE probe can be tracked multi-dimensionally. Currently, the LATITUDE system can track x (axial) position, y (circumferential) position, probe rotation (skew), and can compensate for pipe geometry.

The LATITUDE tracking concept is illustrated in Figure 1. The two green cylinders (R1 and R2) in Figure 1 represent the air-borne ultrasound receivers and the red cylinder (T) represents the air-borne ultrasound transmitter. The transmitter emits an ultrasonic pressure pulse that can be envisioned to travel along paths r1 and r2 to Receiver R1and Receiver R2, respectively. By measuring, with microsecond accuracy, the time it takes for the ultrasonic pulse to travel along both paths, the relative location of the transmitter can be determined by multiplying the time-of-flight measurement by the speed of sound in air. LATITUDE completes this calculation hundreds of times per second, providing a real-time absolute position measurement. With this type of “absolute” position measurement, the probe can be removed from the pipe surface, placed in a different location, and the system will always know the true position of the probe. It does not rely on accumulated encoder “counts” to estimate the position, like traditional scanning systems.

The LATITUDE system consists of three primary components: (1) the transmitter probe fixture, (2) the receiver array, and (3) the electronic control unit. For the case of Phased Array Ultrasonic Testing (PAUT), the electronic control unit directly integrates with the Zetec TOPAZ™ PAUT instrument and control of the LATITUDE system is done through the TOPAZ user interface. The enclosure is sealed, fanless, and can run for up to 12 hours off two hot-swappable batteries, eliminating the need for a 120V power supply.

The receiver array consists of conformable collar that is wrapped around the pipe circumference or stretched along the pipe axis, depending on the application. All wiring for the receiver array is contained within the array housing, with a single connection point to the LATITUDE electronics. While the receiver arrays have been designed to achieve full circumferential coverage on specific pipe diameters, any receiver array may be used for partial coverage on pipe diameters that are larger than the nominal diameter of the receiver array, up to a flat surface.

The LATITUDE transmitter probe fixture contains multiple sensors for determining the axial position, circumferential position, and skew of the fixture. It is typically affixed to an NDE sensor that is being used to conduct an examination, such as a PAUT probe, an eddy current testing (ECT) probe, or any of several other kinds of NDE sensors.


On one end of the spectrum, manual NDE examinations are relatively simple, quick, and do not require any ancillary equipment; however, there is typically no detailed digital record of the NDE data created, meaning that the NDE data is not available for secondary analysis or future reference, if desired. On the other end of the spectrum, fully automated NDE examinations provide a detailed digital record of the examination that can be reviewed and digitally stored for future reference. However, the data acquisition process is much more complicated, requires much more specialized equipment, and the overall examination process typically takes much longer. LATITUDE provides a compromise between these two extremes, minimizing the amount of additional equipment and set-up required while providing a spatially encoded digital record of the examination data.

Relative to automated inspection equipment, several of the primary advantages of a LATITUDE encoded manual examination are:

  • Significantly reduces the average time spent per inspection location
  • Enables the creation of a digital record of the NDE data that can be used for future reference
  • Reduces the number of personnel required for scanning and data acquisition
  • Drastically reduces the amount of equipment needed for examinations
  • Battery power eliminates the need for a 120V power source.
  • Portability and compactness allows quick setup and breakdown when moving between inspection locations


Typical Applications

LATITUDE is simply a position tracking technology and, as such, can be applied to encode the position of many different types of NDE probes. Initially designed for application to pipe ranging from 6” to 36”, the first applications of the technology have been focused on ultrasonic weld examination and corrosion mapping.

In the nuclear industry, Section XI Automated PAUT exams of Dissimilar Metal Welds (DMWs) currently require the use of robotic scanner mechanisms to deliver automated PAUT examinations, which have proven to be both expensive and time-consuming. SI is currently working toward a qualified inspection procedure that incorporates the LATITUDE system to significantly reduce the amount of equipment and number of personnel needed to deliver these encoded examinations. Other weld examination examples where LATITUDE can be used to quickly encode manual scans include UT in lieu of RT and High Energy Piping (HEP) examinations. Figure 2 shows an example of a LATITUDE encoded PAUT scan that was acquired on a girth weld with a 0.306” long, 0.091” deep root crack.



Corrosion mapping is another application that has significant potential to benefit from a LATITUDE encoding approach. When combined with a large-aperture corrosion mapping PAUT probe, critical areas can be mapped very quickly without the need for overly complex probe fixtures, inaccurate string encoders, or slippery encoder wheels. Figure 3 shows an example of a corrosion map that was generated with a corrosion mapping PAUT probe encoded with the LATITUDE system. The entire area (~ 1 sq ft) was mapped in approximately 30 seconds.

These are just several examples of the many possible applications of our new LATITUDE position encoding technology. If you believe that you have an application that could benefit from having a permanent data record or a situation in which automated scanning technologies are simply too bulky or costly, contact Structural Integrity today to discuss the possibilities of a LATITUDE encoded examination.

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