Multi-Sensor Prototype for Non-Destructive Corrosion Evaluation and Characterization

Navy SBIR 24.1 - Topic N241-058
ONR - Office of Naval Research
Pre-release 11/29/23   Opens to accept proposals 1/03/24   Now Closes 2/21/24 12:00pm ET    [ View Q&A ]

N241-058 TITLE: Multi-Sensor Prototype for Non-Destructive Corrosion Evaluation and Characterization


OBJECTIVE: Develop a multi-sensor unmanned aerial vehicle (UAV) system that can assess the condition of a guy wire in situ (in place/position) and identify degradation and potential areas of repair needs before major damage has occurred.

DESCRIPTION: Current UAVs include visual cameras, making visual inspection easily attainable, but cannot view below the surface. Ultrasonic inspection of corrosion on cables requires direct contact with the surface along with the application of a water-based gel, neither of which are easily adapted into a UAV for cable inspection [Refs 1, 2]. Infrared (IR) thermography cannot view more than a few centimeters below the surface and may require high temperatures to provide useful data [Ref 3]. X-ray fluorescence requires extra safety considerations given the outdoor environment. Eddy current testing requires direct contact or near direct contact [Ref 4]. Magnetic flux analysis may require large magnetic fields to provide useful results.

The desire is for a mobile platform that combines multiple sensors and measurement/analysis technologies to provide subsurface corrosion detection along with surface corrosion characterization up to hundreds of feet away from the operator. Basic requirements:

Travel height above ground: 1000ft (T), 1500ft (O)

Travel length in one direction: 1500ft (T), 2300ft (O)

PHASE I: Develop a concept for a UAV system with a multiple Nondestructive Evaluation (NDE) sensor configuration to characterize corrosion and identify areas of further interest. Demonstrate the feasibility of the concept. Prepare a report to ONR / NIWC Pacific on system concept design(s) and sensor output modeling and prepare a Phase II production and testing plan.

PHASE II: Construct a prototype UAV system and assess the accuracy of the corrosion characterization. Provide a report that documents the design options for a prototype system that includes results of operations and type/level/fidelity of corrosion inspection performance. Provide a Phase III plan to ONR 35 / NIWC Pacific for prototype evaluation. Produce a prototype system for NIWC Pacific evaluations.

PHASE III DUAL USE APPLICATIONS: Refine the UAV system and demonstrate corrosion identification, characterization, and analysis. Deliver a UAV system to NIWC Pacific and provide a report containing designs and test data to ONR / NIWC Pacific. The development of a more available option for UAV corrosion assessment would enable remote inspections for a variety of commercial infrastructure applications. Current commercial infrastructure (wind turbine blades, ship hulls, etc.) makes use of a variety of sensor outfitted unmanned systems (UxS); however, none are currently optimized for stand-off, large scale corrosion inspection to the best of our knowledge. Most of the existing commercial options are predominantly fee for service options, vice a complete, off-the-shelf hardware/software asset that is available for procurement.


  1. Zhang, D.; Watson, R.; Dobie, G.; MacLeod, C. and Pierce, G. "Autonomous Ultrasonic Inspection Using Unmanned Aerial Vehicle." 2018 IEEE International Ultrasonics Symposium, pp. 1-4. 10.1109/ULTSYM.2018.8579727
  2. Hernandez-Salazar, C.D.; Baltazar, A. and Aranda-Sanchez, J.I. "Damage Detection in Multi-wire Cables Using Continuous Wavelet Transform Analysis of Ultrasonic Guided Waves." 2009 IEEE Electronics, Robotics, and Automotive Mechanics Conference, pp. 250-255. 10.1109/CERMA.2009.65
  3. Kerdoncuff, H.; Lin, W-I. and Wacker, L.J. "Spectroscopic techniques for corrosion detection using drones." Danish National Metrology Institute, Report DFM-2017-R005, Ver. 1.01, 2017.
  4. Mathey, R. and Clifton, J. "Review of Nondestructive Evaluation Methods Applicable to Construction Materials and Structures." National Bureau of Standards Technical Note 1247, 1988.

KEYWORDS: Corrosion identification; unmanned aerial vehicle; UAV; infrared imaging; eddy currents; magnetic flux; ultrasonic testing; non-destructive materials


The Navy Topic above is an "unofficial" copy from the Navy Topics in the DoD 24.1 SBIR BAA. Please see the official DoD Topic website at for any updates.

The DoD issued its Navy 24.1 SBIR Topics pre-release on November 28, 2023 which opens to receive proposals on January 3, 2024, and now closes February 21, (12:00pm ET).

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Topic Q & A

1/17/24  Q. 1. What is the range of lengths of continuous guy wire that needs to be inspected by this system? (no breakup insulators along the length)
2. Are we able assume short guys near anchors and the ground can be inspected manually/by other methods or systems?
3. Will guy anchors be accessible?
   A. 1. The continuous lengths range from 60 to 500 ft.
2. Areas near the anchors can be inspected from the ground with the same system/method used in the other guy sections.
3. Anchors are accessible.
1/4/24  Q. 1. How are the guy wires being used?
2. Are there environmental (location, external risks, situation, etc.) factors to be aware of?
3. What are the characteristics of the insulating breakups. How big are they? Can you provide any details on the manufacturer / part number / product info if available. Are there pictures in situ available?
   A. 1. These are structural guys.
2. The wires are under tension outdoors in potentially harsh environments.
3. The breakup insulators range in length from 2 to 6 ft and from 12 to 18 in in diameter.
1/3/24  Q. There are currently commercially-available solutions for robotic guy wire inspection, using an MFL tool that can crawl along a guy wire under remote control from the ground. It seems like that technology would meet the general needs expressed in the topic. Can you please indicate what the shortcomings of the currently available technology are that the proposal will need to address?
   A. The guy wires have breakup insulators along the length, which makes a simple crawler not feasible.
12/27/23  Q. How do these defects typically manifest in the materials being inspected?
   A. Currently defects are noticed when they are visible on the outside of the cable.
12/27/23  Q. What are the expectations for the machine learning model regarding accuracy, speed, and reliability?
   A. We would expect it to be accurate and reliable. Further specifications may be developed in later phases.
12/27/23  Q. Are there any limitations of the current technology that we need to address?
   A. Visual inspection through a scope has limitations. Wires have breakups along the length, so currently available crawlers are not feasible.
12/27/23  Q. Are there any specific requirements or constraints for the system (e.g., size, weight, cost)?
   A. No size, weight, or cost considerations at this point.
12/27/23  Q. What defects are we expecting to detect (e.g., cracks, corrosion, voids)?
   A. Corrosion is the priority.
12/27/23  Q. Will we be working with a single material or multiple kinds of materials? This information will help determine the most appropriate approach for model development. (What types of materials will the system be inspecting?). Are these materials homogeneous, or do they have varying properties?
   A. Aluminum and steel.
12/27/23  Q. 1. In a single mission, how many poles with guy wires do we typically need to address?
2. What is the usual length of guy wires that we need to consider?
3. Are there established inspection standards for evaluating corrosion on guy wires and its severity?
4. What factors are commonly identified as the primary causes of corrosion in guy wires?
5. Could you specify the various types of guy wires and their size, coating materials and corresponding thicknesses?
   A. 1. 1 pole
2. From the topic: Travel height above ground: 1000ft (T), 1500ft (O); Travel length in one direction: 1500ft (T), 2300ft (O); breakups exist along the length of the wire
3. Visual inspection from a scope
4. These wires are under tension outdoors in potentially harsh environments
5. The diameter ranges from 1 to 2.5 inches; aluminum, steel

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