A beginners guide to InSAR
This time we’re coming at you with a post that is going to be one of the more technical, informative ones.
So if you’re keen on learning more about satellite monitoring, or more specifically InSAR and what it does, then this is a great place to start, especially if you are new to our blog, so welcome! :)
The million dollar question...
...what in the world is InSAR?
Interferometric Synthetic-Aperture Radar, or InSAR for short, is a remote-sensing radar technique, used for monitoring ground and infrastructure movement.
Simply put, it goes something like this:
The satellites (in our case Sentinel 1) have been orbiting the Earth since 2015, and are revisiting the same spot every 6 or 12 days, giving us historical and new annual data by producing images of the structures and land of the Earth below
and produce A bunch of these images are stacked on top of each other
A smart InSAR wizard (or AI) will compare them to one another. More specifically, compare the signal phase shifts.
Voila! Now you can determine the motion over time of those structures with millimeter precision!
Land movement is normal
Now if land moves all the time anyway, then why should we be concerned? Well, the problem isn’t in this elastic movement. It’s when something moves in one direction and never goes back to its original state.
From the stacked images and the points displayed to us, we can spot this movement with millimeter accuracy and predict the effects it can bring about. In some cases, a single drastic movement can lead to a catastrophe - like this dam, that failed in Brazil in January this year.
The almighty InSAR and its wonders
What makes satellite monitoring so unique and valuable, is that it can produce these images even at night, and in any weather condition, whether it is cloudy, snowing, or storming. It will maintain this millimeter scale accuracy and give us all the desired juicy data over the span of days/weeks/months/years. And we will process it, and have the results for you in no time :)
However, there can be occasions where the satellite can’t pick up any signals from an area of interest, whether it’s because it’s densely vegetated or just not reflective enough. Fortunately, we can simply solve this issue by installing a trihedral metal object, an artificial reflector, which we can also provide from our side.
So what can this technology be used for?
Well, as we mentioned before, we have access to historical data starting from 2015. This data can be used to investigate prior failures as well as compare it to new incoming information, which helps us spot deformation trends and make better risk assessments.
It can be used to monitor any stationary structures or sites including airport runways, dams, pipelines, mining locations, cities, and in case you were wondering - yes even your home :)
Additionally, we can detect ground motion and its subsidence, which can either be caused by subsurface mining or oil/water extractions from reservoirs located underneath the ground.
And well, if you’re concerned about topical issues like sea level rise, then yes, we can do that too :)
For an example, we can take a look at California, where the aquifers are being depleted more rapidly than ever. As the water levels are decreasing, consequently the surface above the aquifer has been subsiding.
This is not limited to just California. It is a global challenge as surface water runoff will no longer absorb to replenish the aquifer rates as naturally intended and abatement is relatively recent. We went into more detail about this in one of our earlier blog posts which you can find here
And this brings us to the end of this blog post. This amazing InSAR wizardry is what we’re best at and spend the vast majority of our time doing - that is, when we're not out here preaching about how great it truly is and how not enough people aren’t already using this :)
And if anyone was wondering, then this awesome little video was what gave us the inspiration for writing this particular post. We know you can’t just help but wonder: “What are this?”