Details

1. Introduction
The DOPPLER VOR TEST RACK test bench is a specialized avionics workstation engineered to validate the performance, reliability, and functional integrity of Doppler VHF Omnidirectional Range (DVOR) navigation beacons and their subsystems. DVOR stations play a critical role in civil and military aviation by providing azimuth information—via the Doppler-modulated 30 Hz signals—to aircraft receivers, enabling accurate en-route navigation and instrument approaches.

2. Key Features
- Universal Module Coverage: Supports both intelligent modules (keyer/interface units, local status indicators) and slave modules (mains power supplies, pulse filters, RF combiners), encompassing over 15 distinct LRUs in one rack.
- Built-In BIT & Fault Isolation: Executes start-up self-diagnostics and guided fault-location routines, reducing mean-time-to-repair by up to 40%.
- Automated Test Sequencing & Reporting: Pre-configured scripts drive RF stimulation, DC power stress tests, and waveform captures; results auto-logged in a centralized database with instant PDF/printable report generation.
- Wideband RF Signal Generation: Covers 960 MHz–1250 MHz with ±0.1 MHz accuracy; power range up to +8 dBm, ensuring compliance with ICAO Annex 10 standards.
- High-Precision Instruments: True-RMS DMM (0.05% basic accuracy), 8-bit PC-based oscilloscope (200 MS/s), AC power analyzer (±0.1%), and programmable DC supply (0–30V, 700 W) for measurement traceability.
- Rugged Design & Power Resilience: MIL-grade cabling, IP65-rated enclosure, anti-glare touch display, and 20-minute UPS backup.

3. Applications
The TB_DVOR is structured into three optimized subsystems:
A. Control & HMI Unit
▹ 15′′ IP65-rated multi-touch LCD with anti-glare glass for clear read-outs under shop lighting.
▹ Backlit full-size keyboard and optical mouse for detailed setup and scripting.
▹ Industrial PC (Intel Core i5, 8 GB RAM, 256 GB SSD) running Windows 10 IoT Enterprise.
▹ Custom .NET GUI featuring drag-and-drop test configuration, multi-user accounts with audit logs, and real-time dashboards.

B. Instrumentation Rack
▹ RF Signal Generator: High-stability synthesizer with Doppler emulation profiles for full azimuth sweep testing.

Measurement Suite:
▹ True-RMS DMM for voltage, current, resistance, and frequency.
▹ PC-attached oscilloscope (200 MS/s) with advanced triggers, FFT analysis, and waveform saving.
▹ AC power analyzer for mains quality, power factor, and harmonic distortion checks.

Power Modules:
▹ 0–30 V, 700 W programmable DC supply with slew-rate control and protection circuits.
▹ Isolated AC mains input with EMI/RFI filters, surge protection, and automatic voltage regulation.
▹ Connectivity & Expansion: Modular backplane supporting GPIB, LXI, and Ethernet I/O cards for future protocol integration.

C. Safety & Diagnostics
▹ Emergency-stop button with hardware interlock to immediately kill outputs.
▹ Tri-color tower light and audio alarms for clear pass/fail/fault indications.
▹ Fold-down maintenance panel granting quick access to wiring looms, test points, and calibration ports without moving the whole cabinet.
▹ Embedded health monitoring logging temperature, fan speed, and UPS status for preventive maintenance.
Built to CE and MIL-STD-810 shock/vibration standards for reliable shop-floor operation.

Technical specifications

  

    
Parameter
    
Specification
  
  

    
Frequency Range
    
960 MHz – 1250 MHz
  
  

    
RF Output Power
    
Up to +8 dBm max
  
  

    
DC Power Supply
    
0–30 V DC, 700 W programmable, adjustable slew rate, over-voltage/current protection
  
  

    
UPS Backup
    
20 minutes battery-backed operation
  
  

    
Enclosure Rating
    
IP65, weatherproof industrial cabinet with MIL-grade cabling & connectors
  
  

    
Industrial PC
    
Intel Core i5, 8 GB RAM, 256 GB SSD, Windows 10 IoT Enterprise
  
  

    
Display
    
15” capacitive multi-touch, anti-glare, IP65 front, 10-finger capacitive touch
  
  

    
Digital Multimeter
    
Panel-mounted True-RMS (voltage, current, resistance, frequency)
  
  

    
Oscilloscope
    
8-bit A/D, 2 channels, 200 MS/s, advanced trigger modes, USB 2.0
  
  

    
AC Power Analyzer
    
±0.1 % accuracy, measures mains quality, power factor, harmonics
  
  

    
Circuit Breaker
    
16 A manual/automatic protection
  
  

    
Operating Conditions
    
0 °C to 50 °C, up to 95 % non-condensing humidity
  
  

    
Dimensions (HxWxD)
    
2000 mm × 600 mm × 800 mm (standard 19” rack)
  
  

    
Weight
    
Approx. 250 kg (fully loaded)
  



4. Principle of Operation
▹ Initialization & BITE: On power-up, built-in test equipment runs self-checks across power, signal, and communication lines.
▹ Module Selection & Configuration: Operator selects SRU profile via GUI; system auto-loads stimulus and measurement parameters.
▹ Doppler Sweep & Measurement: RF generator emulates rotating antenna; oscilloscope and multimeter capture data to compute azimuth accuracy.
▹ Tolerance Comparison & Fault Flagging: Real-time readings compared against tolerances; out-of-spec points trigger alarms.
▹ Report Compilation: Data logs, waveform snapshots, and summaries compiled into standardized test reports.

5. Workflow & Test Procedure
▹ Pre-Test Setup: Inspect and connect UUT via MIL-grade connectors; verify UPS and mains input quality.
▹ Software Configuration: Select module type, test script, and environmental parameters.
▹ Automated Execution: Launch test sequence; system applies RF, DC, and monitors safety interlocks.
▹ Real-Time Monitoring: Live graphs for amplitude vs. time, phase vs. azimuth, and power stability with immediate threshold alerts.
▹ Post-Test Actions: Review and archive the report; disconnect UUT and record maintenance notes.

6. Calibration & Maintenance
▹ Traceable Calibration: Annual calibration of DMM, oscilloscope, and RF generator against national standards (ISO/IEC 17025).
▹ Quick-Access Maintenance: Fold-down backdoor panel offers direct access to wiring and test points, minimizing downtime.
▹ Software Updates & Extensions: Remote firmware and GUI updates supported; new script packages can be installed without hardware changes.
▹ Environmental Checks: Regular inspection of rack seals, fan filters, and UPS battery health for long-term reliability.

7. Conclusion
By combining comprehensive DVOR module coverage, automated BIT routines, precision instrumentation, and an intuitive HMI, the TB_DVOR delivers a future-proof platform for avionics maintenance and certification labs. Its modular architecture, robust design, and compliance with international navigation standards make it indispensable for ensuring flight-critical navigation aids remain within stringent performance thresholds.