Necto Aviation
Independent ATM & Surveillance Validation
ED-117 MLAT Validation
Understand Multilateration performance before it impacts operations
ED-117 validation ensures that multilateration (MLAT) systems meet required performance standards for airport surveillance. By analysing accuracy, geometry, latency and tracking behaviour, hidden performance issues are identified before they impact operational safety.
Who this is for
Operators of MLAT surveillance systems who need to confirm that real-world performance matches expected ED-117 requirements. Especially relevant after installation, system changes, or when performance concerns arise.
Why this ED-117 analysis
Without independent validation, there is no objective proof that your MLAT system performs as intended.
ED-117 validation delivers clear, data-driven insight into system behaviour, ensuring confidence in surveillance performance.
Scope note:
Only site testing is performed. No product, factory, or laboratory testing. Validation covers on-site configuration, alignment, and operational performance.
Two use cases apply:
●Interim Site Health Scan to confirm stable performance over time.
●Independent Acceptance Check prior to operational handover.
What we test for ED-117
All testing is performed in line with Chapter 6 of EUROCAE ED-117, focusing on on-site performance verification of the deployed MLAT system.
The analysis covers:
● Coverage across the defined movement area, including identification of coverage gaps
●Position accuracy and consistency under operational traffic conditions
●Track behaviour, including track initiation, maintenance, and termination
●False tracks and unintended track generation
●False identification, including target mis-association
●Problem areas related to geometry, layout, or site-specific constraints
Testing reflects the scenarios, methods, and acceptance criteria defined in ED-117 Chapter 6, applied to the operational site configuration.
A full MLAT validation campaign requires structured test activity and operational coordination. The Necto Quick Check takes a different approach. By analysing normal operational data we review the behaviour of the complete surveillance chain, including A-SMGCS tracking, MLAT inputs and Surface Movement Radar performance. This provides a fast indication of overall surveillance behaviour without requiring dedicated test activity on the airfield.
How we work
The validation process follows four main stages.
During the intake phase, we establish an overview of the system, the airport layout, and the agreed baseline for the analysis.
This is followed by test planning, where the relevant scenarios are defined, traffic samples are selected, and the required data access is arranged.
In the execution phase, independent data collection is performed on-site while the system operates under normal live conditions.
Finally, the reporting phase consists of analysing the collected data and presenting the findings in a structured report with clearly documented results.
Deliverables
The results are delivered through an interactive online report that presents the outcome of the ED-117 validation in a clear and traceable way. Each relevant ED-117 parameter is assessed with a pass/fail result, with the ability to drill down directly to the supporting measurement data.
The report also includes a concise summary statement that provides an overall view of system conformity. When the system meets the applicable requirements, a statement of conformity is issued. If deviations are identified, these are documented together with a proposed remediation plan to support follow-up actions and potential corrective measures.
Standards and references
Testing is performed against one of the following, agreed at kick-off:
● EUROCAE ED-117 (Multilateration requirements), or
● ETSI EN 303 213 (Multilateration performance requirements, relevant parts)
Timeline and pricing
An ED-117 validation project typically starts with a preparation phase of around two weeks, during which the system layout, sensor geometry and relevant test conditions are reviewed. The on-site campaign itself is usually completed within one week, after which the recorded data is evaluated and documented in the final report over the following two weeks.
The overall effort varies with the local airport environment, operational limitations and the extent of the selected validation scope.
A tailored proposal can be prepared based on the local situation and the modules to be included in the campaign. Please contact us to discuss your requirements.
Questions about MLAT performance validation?
ED-117 validates Multilateration sensor performance, while ED-87 evaluates the complete A-SMGCS with all surveillance inputs combined.
Where Multilateration provides one layer of surveillance, ED-116 concentrates on Surface Movement Radar performance
Looking to evaluate MLAT performance or understand how it fits within your overall surveillance system? We are available to review your setup and advise on the next steps.