An Add-On Solution for RNAV Procedures Flight Checks
Today’s increasing air traffic requires an increase in airspace capacity and flexibility of its use. Therefore an increasing number of area navigation (RNAV) based procedures are established. They provide routings in addition to the straight-line connections between the positions of ground based navigation aids or track segments to or from these conventional aids. RNAV permits the definition and use of instrument departure, en-route, terminal and also instrument approach procedures.
For use of these procedures, RNAV capable navigation systems are required. Typically these navigation systems are multi-sensor systems (GPS/FMS) based on GNSS, VOR/DME, DME/DME and/or IRS.
RNAV procedures contain waypoints, whose positions are not necessarily defined relative to ground-based navaids, but by geographical coordinates (WGS84) only.
The waypoint definition by use of coordinates stored in data bases, together with the possible absence of corresponding ground based reference points, require an extended and modified flight inspection concept to maintain a high level of navigation accuracy and therefore flight safety.
For flight safety reasons, the accuracy and reliability of navigation systems and procedures have to be proven. Technical and environmental conditions are changing dynamically (e.g. obstacle situation, navigational information, electromagnetic interference, characteristics of radio facilities). Therefore not only commissioning inspections for new navigation procedures have to be done, but also periodic inspections for established procedures on a regular basis as well.
All procedure related elements need to be inspected:
- Waypoint Accuracy - Bearing Accuracy
- Distance Accuracy - Navigation Sensor Accuracy
- Conformity with ground based Navigation Aids
- Communication Coverage
- Radar Coverage
- Receiver Autonomous Integrity Monitoring (RAIM)
- Approach Lighting System
Flight inspection of RNAV procedures consists not only of flying and evaluating the procedure but also of checking all navigational data for completeness and correctness.
AD-RNAV Flight Inspection System
The RNAV Flight Inspection System AD-RNAV is an add-on to existing conventional Flight Inspection Systems.
The AD-RNAV enhances existing flight inspection systems to be fully capable of inspecting RNAV procedures and helps to fulfil RNAV FI requirements without the need to purchase a full new System.
The key components of the AD-RNAV are:
Equipment Box containing:
- Data Acquisition Module
- Positioning Module
- Real-time Module
Display Computer (Laptop) including
- RNAV Flight Inspection Software Package
The Equipment Box is a small rugged portable housing containing the Data Acquisition-, the Real-timeand the Positioning-Module. It provides all data and power interfaces to the existing flight inspection system and to the aircraft navigation sensors.
Data Acquisition Module
The AD-RNAV interfaces the following aircraft navigation equipment:
- Aircraft Flight Management System (FMS)
- Inertial Navigation System (INS)
- Aircraft Air Data Computer (ADC)
For reference position determination the Data Acquisition Module interfaces the following AD-RNAV integral receivers:
- GPS receiver
- Wide Area Differential GPS receiver (Option)
- Phase Tracking Differential GPS (Option)
The I/O board used for data acquisition in the ADRNAV is a standard interface board of TSO’d navigation equipment.
For evaluation of RNAV procedures and determination of navigation system accuracy the flight inspection system requires precise reference position. The reference position of the AD-RNAV is provided by the Positioning Module. The following receivers are part of the Positioning Module:
- Wide Area Differential GPS (optional)
- Phase Differential GPS (optional)
By using each of the available sensors fused to one hybrid position solution the AD-RNAV reference position reaches an unrivalled level of accuracy and integrity.
- Wide Area Differential GPS using the OmniStar satellite network provides improved accuracy without any ground reference equipment
- Highest reference position accuracy is required for flight inspection of RNP precision approaches in the future. Therefore the ADRNAV is also available with Phase Tracking Differential GPS (PDGPS).
The Real-time Module controls the Data Acquisition Module and the Positioning Module. This module provides precisely time-stamped reference position data and sensor data with 10Hz to the display computer where it is analysed by the RNAV Flight Inspection Software.
The Display Computer of the AD-RNAV is a high-end, portable Laptop computer:
- Pentium M Processor: ³ 2 GHz
- Hard disk: ³ 60 GB
- Memory: ³ 1 GB
- Display: ³ 15 “
The display computer with its comfortable Graphical User Interface (GUI) is the front end to the Flight Inspector. Via keyboard and touchpad (or mouse) the flight inspector may set-up the system in a windowslook- and-feel manner; all modules of the system (Real-time Module, Positioning Module and Data Acquisition Module) are fully remote controlled by the display computer.
RNAV Flight Inspection Software
General features of the Aerodata RNAV Flight Inspection Software:
- Easy-to-learn user surface
- 10Hz data recording in office-compatible data format
- Interface to standard office software packages
- Full Replay Functionality
- Menu, keyboard and dedicated function keyboard operation.
- Automatic report generation
- Electronic Flight Instrument System
- Fully compatible to AD-AFIS series for an easy upgrade path
Printing of graphics and alphanumeric windows and reports can easily be done in-flight on the printer of the existing Flight Inspection System or post flight on any office printer in full color.
The RNAV Flight Inspection Software allows evaluating the following parameters:
- RNAV Procedure Waypoint Accuracies
- RNAV Procedure Bearing Accuracies
- RNAV Procedure Distance Accuracies
- RNAV Navigation Errors - GNSS Signal Coverage
- RAIM Status
- Conformity of ground based Navaids
Numerous RNAV-specific Graphic and Alphanumeric windows with suitable parameter compilation are available and may be opened and viewed simultaneously:
Situation Awareness Displays:
For situational awareness the RNAV Flight Inspection System provides an Electronic Flight Instrument System (EFIS) with Primary Flight Display (PFD), Multifunction Display (MFD) and a Moving Map Display based on Jeppesen Data.
The AD-RNAV with its modular architecture is fully prepared for future enhancements like CNS/ATM capabilities like ADS-B, VDL etc.