Report

Teaser, summary, work performed and final results

Periodic Reporting for period 3 - NAVISAS (Navigation of Airborne Vehicle with Integrated Space and Atomic Signals)

Teaser

Airspace is a precious resource subject to mounting demand by all types of users (airliners, small aircraft, helicopters, balloons and drones). To cope with demand there’s been increasing dependence on satellites (such as GPS) to help air navigation. The problem is if those...

Summary

Airspace is a precious resource subject to mounting demand by all types of users (airliners, small aircraft, helicopters, balloons and drones). To cope with demand there’s been increasing dependence on satellites (such as GPS) to help air navigation. The problem is if those satellites fail, the current navigation systems will not be able to cope with the amount of users or deliver the expected performance. Moreover, small aircraft and drones generally do not have access to existing navigation systems equipment.
The NAVISAS project aims to develop a concept for small aircraft to obtain alternative positioning, navigation and timing (APNT) information when satellite navigation fails while keeping performance and efficiency consistent with the airspace requirements. NAVISAS will achieve this goal by merging satellite navigation based on multiple constellations (e.g. GPS and GALILEO) with an advanced inertial measurement unit (IMU) based in atomic gyroscopes implemented using microelectromechanical systems (MEMS) technology (as represented in Figure 1).
NAVISAS will pave the way for a new cost effective instrument that can be used by small aircraft to ensure navigation performance levels consistent with evolving airspace and air traffic. The NAVISAS concept aims at improving the flight safety level, as well as the ATM performance and efficiency.

NAVISAS aims to investigate the feasibility, specifications and limits of an APNT concept grounded on the merger of multi-constellation GNSS based navigation with an advanced inertial measurement unit (IMU) based in atomic gyroscopes implemented in MEMS technology. Multi constellation GNSS navigation requires stable timing references. The consortium proposes to integrate atomic clocks in the concept and in particular investigate how an atomic clock can be integrated with an atomic gyroscope in the MEMS cell fabrication process and same physical package.
These analyses will be followed by assessment of the impact of this concept on both safety and performance of small aircraft as well as of the ATM system.
Finally, this project aims to prepare a development roadmap that will enable the consortium to understand how this concept can be further matured, deployed and adapted to other aircraft beyond small aircraft in operations under Visual Flight Rules (VFR) and Instrument Flight Rules (IFR).
For the purposes of NAVISAS, small aircraft include the following vehicles:
• Ultra Light (UL) Aircraft, generally understood to be single- or two-seater fixed wing or rotorcraft with a Maximum Take-Off Weight (MTOW) below 600Kg (a complete definition of UL aircraft provided in deliverable D2.1).
• Very Light Aircraft (VLA) as defined by the European Aviation Safety Agency (EASA) in its certification specifications (CS-VLA).
• Normal, utility, aerobatic and commuter aeroplanes as defined by EASA in its certification specifications CS-23.
• Remotely Piloted Aircraft Systems (RPAS) or Unmanned Aerial Vehicles (UAV) as defined by EASA in its proposed amendment for the introduction of a regulatory framework for the operation of drones.

Work performed

During the first period NAVISAS focused on the definition of NAVISAS requirements. The consortium established a process to derive the requirements, analysed and discussed which aspects constituted true requirements for NAVISAS and produced a document compiling the conclusions and results of that analysis.

Furthermore, the consortium developed a preliminary conceptual design of the NAVISAS system and defined its functional block diagram taking into account navigation, operational, end user and aeronautics points of view and related requirements, as well as the SESAR’s vision for future ATM operations (SESAR European ATM Master Plan). Requirements for each component were presented.

Finally, the team identified design assurance standards and environmental and performance constraints specific to commercial aircraft which might impact NAVISAS with a view towards potential future exploitation of the project results in commercial aviation. A preliminary plan for the integration of this kind of system in aeronautics was proposed and the possible market which is available in the future for the application of this technology was estimated.

For the second period of NAVISAS, the consortium established the state of the art in terms of navigation techniques specifically for small A/C as defined by the project and commercial aviation in general and in the field of atomic clocks and atomic gyros. It also defined and carried out a number of experiments designed to clarify the state of the art on the integration of atomic clocks and atomic gyros and to progress the TRL of both technologies. Finally, the consortium determined that at the current stage of development of the project and given that a block diagram explaining the different blocks of NAVISAS was already proposed during reporting period 1 it would not make sense to carry out these activities as the team would be repeating work from period 1 and unable to progress more on the detailing of the blocks. Alternatively, it was agreed that NAVISAS was missing an operational concept for small A/C. Therefore, the consortium agreed to pursue the development of one or more operational concepts that explain how the consortium envisages the usage of NAVISAS by the small A/C universe. The idea behind this is for the operational concepts to provide a bigger picture on what value NAVISAS can bring to small aircraft and help understand what is achievable and under what conditions. As such, the consortium has proposed 4 concepts where small aircraft can benefit from NAVISAS technology.

In the third period the consortium has been developing the advanced concept for the NAVISAS system. Tests claryfing the state of the art in integration of atomic clocks and atomic gyros were continued and their results gave significant input to the development of concept for micro-gyro and combined atomic clock. Tests have not been completed yet due to the unforseeable accident. Partners have been assessing other technologies and trade-offs of their application to NAVISAS. The team proposed a vision-based element to complement NAVISAS system and improve its performance. The consortium has been preparing a small aircraft for testing campaign of this solution. GNSS&INS coupling methos are investigated in order to identify the optimal solution implementation route. The literature review on coupling techniques will be followed by trade-off assessment and simulations. Simulations for hybridized dual-constellation / inertial position have been performed already.

Final results

During the second reporting period, the consortium has been able to push the technology readiness level of the atomic clocks and atomic gyros proposed for use in NAVISAS to TRL2.5. This was achieved by carrying out a number of lab experiments, namely:
- Manufacture MEMS cells and run tests to characterise them;
- Create a lab setup to carry out the tests of the NAVISAS technology roadmap;
- Residual fields measurements

Some results of laboratory tests performed to measure key parameters of interest for the technologies of interest were obtained and the partners believe these can validate some of the assumptions of the previous maturity level concerning aspects like performance.

The team progressed on NAVISAS APNT concept and prepared an aircraft testbed for testing.

Website & more info

More info: http://navisas.tekever.com/.