A well-written InSAR monitoring specification helps procurement teams get the full value of satellite monitoring. It describes the asset decisions, the evidence expected, quality controls, responsibilities and acceptance criteria, rather than simply demanding "millimeter accuracy" or the highest possible point density. Those requirements can be misleading when site conditions, satellite geometry and the consequences of a wrong interpretation have not been defined.
Write the problem statement first
State what is being monitored, why movement matters, who will use the outputs and what actions might follow. For a highway agency, the problem may be prioritizing surveys along a long corridor. For a tunnel project, it may be establishing pre-construction movement and tracking changes within a defined zone of influence. For a mine, it may be regional screening alongside the site's existing safety monitoring. You can read more about how the method works in SkyGeo's introduction to InSAR.
Be clear about the intended application. Historical characterization, recurring assessment and critical operational alerting are different services. Periodic satellite measurements should never quietly stand in for instruments that must warn crews of rapidly developing hazards.
Define the technical scope without overconstraining the method
Provide the area boundary, asset inventory, relevant time period and any known access or ground cover constraints. Ask bidders to explain their satellite choice, viewing geometry, acquisition schedule, processing method, reference framework, coverage gaps and data quality treatment. If several satellite datasets will be used, ask how the measurements will be made comparable.
Specify whether you need relative line-of-sight displacement, a justified estimate of vertical motion or a validated solution combining several viewing geometries. If the expected direction of motion is important, say so. Ask for evidence of coverage on representative structures rather than accepting an average point density for the whole area.
Make outputs testable
A useful deliverable schedule defines file formats, coordinate system, unique point IDs, acquisition dates, reference period, quality indicators, uncertainty treatment and access to time series. For management, require an interpretation of noteworthy changes, their potential significance, alternative explanations and the recommended next action. State whether you expect a GIS-ready export, a web platform, a PDF report and a technical review meeting. For a wider practical overview, you can download The Ultimate Guide to Using InSAR.
Acceptance tests can include an agreed pilot area, inspection of sample time series, comparison with available ground observations and confirmation that the supplier can reproduce results when processing assumptions change. The aim is not to prove that every point agrees perfectly, but to understand discrepancies and confirm the output is fit for purpose.
Clarify responsibilities when conditions change
Define who reviews alerts, who can request reprocessing, how missing observations are reported and what happens when major construction or vegetation change disrupts coherence. Name the technical contact for interpreting unexpected movement, and agree how changes in scope will be approved and priced.
For long-running programs, require a versioned record of processing changes, not just an updated dashboard. Historical comparability and traceability become especially important when the data is later used for investigations or assurance.
Red flags at the tender stage
Question any promise of universal accuracy, complete coverage, failure prediction or "real-time" performance that is not backed by a site-specific demonstration. A strong proposal openly addresses measurement direction, uncertainty, latency and where independent instruments are still needed.
We welcome being assessed against the same transparent criteria as any other specialist provider. A clear specification makes it easier to choose the right monitoring service and to judge whether it is performing as intended.
Frequently asked questions
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Not unless there is a clear operational reason. Define coverage, evidence quality, reporting and review requirements, then ask bidders to justify their sensor configuration.
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Ask for examples that show reference choices, data quality, limitations and how uncertainty affects decisions. Avoid accepting a single blanket guarantee of millimeter accuracy.
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The specification should state whether the supplier only reports observations or also helps with interpretation, and it should name the client's responsible reviewer and escalation route.
Get a second opinion on your specification
If you are preparing a monitoring tender, SkyGeo can discuss which InSAR requirements make sense for your project. Contact SkyGeo.
