That Sinking Runway Feeling
Deformation Data - PSinSAR
Supporting Airport Operations
Data, data everywhere
For me, getting started in InSAR was like discovering a new kitchen. It’s as though you had never heard of hispanic culinary life and walked into a Mexico City restaurant for the first time. The ideas of what you could do with the ingredients seem endless. I image that it’s this way for most folks who first get exposed to the concept of being able to monitor deformation accessibly without ever visiting the actual location. I can literally sit at my laptop anywhere in the world and pull up data on anywhere in the world :)
The adventure really kicks in when you start to prepare your first meals with these new ingredients and you find what works well. Airports and InSAR are like avocados and tacos. They just go together, period. We’ve just begun to scratch the surface of what we can do to aid in a space where this technique can be most helpful. I am certain that we will be creating new recipes of avocado and taco combinations for a long time to come but we wanted you to see a bit of what we have found so clever about this so far.
Unique environments, unique solutions
Airport terminals are operating in environments where reactive maintenance and shut downs are not an option. Posing a challenge for traditional on-site monitoring techniques and pushing operators and maintenance teams to, at best, use annual LiDAR observations as part of their GIS asset management catalogue or spot surveying with drone systems flying photogrammetry. Many operators are simply unaware of the gradual deformation typically the result of drainage and geotechnical characteristics.
Such deformation feeds directly into the maintenance and physical plant asset life cycle of terminal operations in the form of increased runway pavement periods, premature infrastructure life cycle shortening (jet bridge, hangar, mass transit connection), and complicating response to geohazards from flooding and seismic activity.
Synthetic aperture radar grants terminal operators a unique ability to passively all-weather observe the deformation of their operation area with lower cost and higher accuracy than any contactless long-term monitoring technique. Persistent scatter interferometry, the technique employed by Sille, gives an edge to SAR through its talent to determine millimeter accuracy across wide areas. Sille employs an AI to develop this data and to visualize those results in a web-GIS in a cost effective and easily interpretable fashion.
Ovela, the American operation of Sille, has deployed the platform in Charleston, West Virginia - the state’s most important airport. With studies together with the State of Maryland in Baltimore, and the US Navy in Norfolk, Virginia. Needing a level airfield and operations area often means ‘filled’ land that is prone to long term deformation from water runoff handling. This issue is particularly acute in coastal areas where airport operations can share a boarder with a water body. Increases in dramatic rainfall events have challenged the water handling of airports globally. In an environment where a few centimetres of deformation can result in runway / taxiway changes deformation information is critical.
Charleston, West Virginia
Yeager airport was built atop two mountains that had their tops removed and leveled for the construction of the terminal and runways. This has inevitably led to a history of deformation along the periphery of the operations area. Being the largest airport in its region, and home to a military air operations center, it is a key asset to the State of West Virginia.
Yeager’s primary runway was extended to accommodate an aircraft arresting system EMAS to prevent any aircraft skidding off the end of the runway from falling from the mountain. To construct this arresting system a massive amount of material was added to the end of the mountain with a retention wall. Several years ago an aircraft over shot the runway and was saved by this countermeasure. However, shortly thereafter a massive landslide resulting in that addition to the mountain and the arresting system falling into the village below.
Yeager has since retained Schnabel Engineering, as the principal firm for the project, to reconstruct the airport retaining wall and safety systems. Schnabel Engineering and Yeager Airport began working with Ovela to monitor that process and the entire airport operations area. This summer the new retention wall and EMAS system was completed.
The significant geohazard areas of airport operations are regularly monitoring by Ovela using the Sentinel 1 data set in conjunction with Schnabel interpretation and analysis of the deformation points. The airport authority has also constructed and tested several radar reflectors to use in vegetated areas of the facility. This is together with a series of traditional ground sensors which are networked to a sensemetrics monitoring system. They have created a fantastic write up of their work on this site here.
This technique will save Yeager Airport Authority thousands of dollars as it replaces manual surveying methods that had to be conducted monthly. Together with the team at Schnabel this work has reduced risk of the site and added tremendous value to airport operations.
Toronto, Ontario – Canada
One of the largest airports in the world, Toronto serves millions of passengers from Canada’s largest city. Together with airport engineering staff Ovela has provided a historic analysis of the deformation areas of the runways and terminals. In this process Toronto airport authority was able to identify an area of consistent repaving operations that corresponds to subsidence from drainage shown on Sille results.
Correction of this issue can save Toronto airport untold delays and cost from maintenance to that runway. In the area below these areas of concern are shown as uplift in blue and subsidence in yellow/red.
Baltimore, Maryland - BWI
An airport terminal in an area with frequent de-icing operations and arguably one of the most sophisticated treatment systems to handle the fluid runoff from the aircraft. However, the catch basin for that fluid is subsiding, as are the adjacent taxi ways. Sille historic results were able to indicate to Maryland Environmental Services the rate at which maintenance activities would need to occur.
Complementing LiDAR and any GIS systems
Many airport operators will have annual LiDAR data gathered of their facilities. InSAR is an excellent corroborator to that effort. The techniques are certainly not either/or but rather supportive of each other. LiDAR is able to show the details of specific structures like an ultra resolution image - depending on the LiDAR. PSinSAR, particularly from Sentinel 1 is able to show the areas of long term concern and allow you to focus on where and what to address when.
LiDAR data, and all other operations information is often kept in a operations/engineering GIS system for reference and asset management. InSAR data, as ours, is easily added to that system without much effort and with a great deal of benefit - you can see how things are moving alongside the other data you’ve collected there.