CLX SIMS: Sensor Integrated Monitoring System for Intelligent Airport Operations

Executive Summary

Airport gate operations rely on a complex network of electromechanical systems, varied control platforms, and operational processes that must function with high reliability and precision. Despite this, many airports continue to operate with limited system-level visibility, relying on localized HMIs and reactive maintenance practices that do not provide a complete picture of performance.

CLX SIMS (Sensor Integrated Monitoring System) addresses this gap by introducing a structured, data-driven monitoring architecture that integrates directly with existing control systems while extending visibility through sensor-based instrumentation and centralized analytics.

SIMS combines:

• Direct PLC and VFD integration

• Distributed sensor networks at the gate level

• A centralized Upper-Level platform for visualization, alarms, and reporting

This approach enables airports to move beyond isolated system monitoring toward a unified operational environment, improving situational awareness, reducing downtime, and enabling predictive, condition-based maintenance strategies.

Introduction: The Challenge of Fragmented Gate Systems

Airport gate infrastructure consists of multiple interdependent systems, including:

• Passenger Boarding Bridges (PBB)

• Pre-Conditioned Air (PCAir) units

• Ground Power Units (GPU)

• Docking guidance systems (VDGS / Safegate)- where so equipped

• Control panels and supporting electrical systems

While these systems interact operationally, they are typically monitored independently. Data is often confined to local PLCs or HMIs, limiting the ability to:

• Correlate events across systems

• Analyze performance trends over time

• Identify root causes of operational issues

• Optimize maintenance and resource allocation

This fragmented approach introduces inefficiencies and risk, particularly in high-throughput environments where small delays or failures can propagate across operations.

SIMS is designed to eliminate these gaps by creating a unified monitoring layer that spans all gate systems.

System Architecture Overview

SIMS is based on a layered architecture that separates data acquisition from data visualization and analytics, ensuring scalability and minimal disruption to existing operations.

Primary Components

• Gate-Level Monitoring Layer (Edge Layer)

• Centralized Upper-Level Platform (Supervisory Layer)

Architecture Characteristics

• Non-intrusive integration with existing PLC logic

• Ethernet-based communication infrastructure

• Scalable deployment across gates, terminals, and entire airports

• Modular design allowing phased implementation

This architecture enables real-time data collection at each gate while consolidating information into a centralized environment for system-wide visibility.

Gate-Level Monitoring Layer

At the gate level, SIMS deploys a dedicated Ethernet network that interfaces directly with existing PLCs, VFDs, and field devices. This network is designed to operate independently of control networks where required, ensuring secure and reliable data acquisition.

• Integration Approach

• Direct communication with PLCs (e.g., Allen-Bradley)

• Data extraction from existing control logic and tags

• Supplemental sensor deployment where additional data is required

• Encoder feedback utilization for positional accuracy

No modification to control sequences is required, allowing SIMS to be deployed with no impact to operations.

Monitored Systems and Data Points

SIMS captures both discrete states and continuous analog data across all major gate systems.

Passenger Boarding Bridge (PBB)

• Docked vs. stowed state

• Docking duration and utilization metrics

• Canopy extension and auto-level positioning

• Tunnel extension, elevation, and rotation

• Cab, rotunda, and bogie angles (via encoder feedback)

• Fault states and operational interlocks

PCAir (Air Handling Unit)

• System status (on/off) and runtime accumulation

• Temperature measurements:

  • Ambient air

  • Inlet air

  • Discharge air

  • Cabin air

• Discharge air pressure

• Blower motor current and load characteristics

Ground Power Unit (GPU)

• System status (on/off) and runtime

• Output voltage per phase

• Output current per phase

• Load balancing and electrical performance indicators

• Fault conditions and protective states

Data Acquisition Characteristics

• High-frequency polling or event-driven updates

• Time-stamped data collection for accurate sequencing

• Normalization of data across different equipment types

• Edge-level buffering to prevent data loss

All data is transmitted to the Upper-Level platform for aggregation and analysis.

Upper-Level Platform (Supervisory Layer)

The SIMS Upper-Level is built on the Ignition SCADA platform, providing a scalable, web-based interface for monitoring, visualization, and system interaction.

Core Functionalities

• Centralized graphical interface across all gates and terminals

• Real-time visualization of system states and equipment performance

• Hierarchical navigation from system-level to device-level views

• Role-based access for operators, maintenance, and management

System-Wide Visualization

The Upper-Level provides a comprehensive operational overview, including:

• Gate occupancy and aircraft presence

• Docking status and duration

• High-level equipment states (PBB, PCAir, GPU)

Users can drill down into individual gates to access detailed diagnostics, including:

• Positional data (height, extension, angles)

• Equipment performance metrics

• Active faults and alarms

System Integrations

SIMS supports integration with external systems to enhance contextual awareness:

• VDGS / Safegate systems

  • Aircraft docking status

  • Positioning data

• Flight Information Systems

  • Aircraft type

  • Flight number

  • Origin/destination

• Operational Data Sources

  • Tower or airline data feeds

  • Third-party system interfaces

This integration enables SIMS to correlate equipment performance with operational events.

Data Management, Alarming, and Reporting

SIMS is designed to convert raw data into structured, actionable insight.

Data Management

• Full data historization within the Upper-Level platform

• Long-term storage for trend analysis and reporting

• Time-synchronized data across all systems

Alarming and Event Handling

• User-configurable thresholds and setpoints

• Real-time alarm generation based on operating conditions

• Event logging with precise time correlation

• Multi-condition alarm logic for complex scenarios

Reporting Capabilities

SIMS provides a flexible reporting framework that supports both operational and strategic use cases.

Standard reporting includes:

• Equipment runtime and utilization

• Fault and alarm frequency analysis

• Performance trends across gates and systems

• Maintenance-related metrics

Custom reporting capabilities:

• Stakeholder-specific KPIs

• Airline or terminal-specific metrics

• Exportable data formats for further analysis

Reports can be generated on demand or scheduled for automated distribution.

Predictive Maintenance and Analytics

SIMS enables a transition from reactive and time-based maintenance to condition-based maintenance.

Analytical Approach

• Continuous monitoring of key performance indicators

• Trend analysis across historical datasets

• Identification of deviations from baseline operation

Early Indicators of Degradation

• Increased motor current indicating mechanical resistance

• Temperature drift suggesting HVAC inefficiencies

• Voltage/current imbalance in GPU systems

• Extended docking durations indicating operational constraints

Operational Impact

• Reduced unplanned downtime

• Improved asset lifespan

• Optimized maintenance scheduling

• Reduced maintenance costs

By aligning maintenance activities with actual system conditions, SIMS improves both reliability and efficiency.

Integration with Intelligent Gate Operations 

SIMS is designed to support advanced and autonomous gate environments. 

When integrated with: 

• Autonomous Passenger Boarding Bridges 

• APPS (Automated Pilot Parking System) 

• Pushback Tugs (Autonomous & Manual) 

• Baggage Loaders (Autonomous & Manual) 

• Baggage Tugs 

• Future AGVs

SIMS provides the monitoring and validation layer required for coordinated operation. 

Capabilities 

• Real-time validation of equipment readiness 

• Monitoring of docking and turnaround sequences 

• Cross-system visibility between aircraft and gate infrastructure 

• Feedback loops for operational optimization 

This enables a fully connected gate ecosystem where systems operate cohesively. 

Operational and Strategic Benefits 

Operational Benefits 

• Improved situational awareness across all gate systems 

• Faster fault identification and resolution 

• Reduced operational disruptions 

Maintenance Benefits 

• Transition to condition-based maintenance 

• Reduced emergency interventions 

• Improved resource allocation 

Strategic Benefits 

• Scalable platform for airport-wide deployment 

• Foundation for future automation initiatives 

• Data-driven decision-making capabilities

SIMS Summary

CLX SIMS provides a comprehensive solution for modernizing airport infrastructure monitoring without requiring system replacement. 

By integrating directly with existing control systems, deploying sensor-based monitoring at the edge, and delivering centralized visibility and analytics, SIMS transforms how airports manage gate operations. 

The result is a unified, intelligent monitoring platform that improves reliability, reduces cost, and enables the next generation of airport automation.