Navigation of Airborne Vehicle with Integrated Space and Atomic Signals

Project Information

NAVISAS

Grant agreement ID: 699387

DOI

10.3030/699387

Project closed

EC signature date 11 February 2016

Start date 1 March 2016

End date 28 February 2018

Funded under

• SOCIETAL CHALLENGES - Smart, Green And Integrated Transport

Total cost

€ 890 910,00

EU contribution

€ 584 978,75

Coordinated by

TEKEVER ASDS
Portugal

Periodic Reporting for period 4 - NAVISAS (Navigation of Airborne Vehicle with Integrated Space and Atomic Signals)

Reporting period: 2017-06-01 to 2018-02-28

Summary of the context and overall objectives of the project

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.

NAVISAS developed 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 investigated the possibility of merger of satellite navigation based on multiple constellations (e.g. GPS and GALILEO) with an advanced inertial measurement unit (IMU) based on atomic gyroscopes implemented using microelectromechanical systems (MEMS) technology.

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 (addresing safety and efficiency). For the purposes of NAVISAS, small aircraft includes:
• 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.
• 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.

The outcome of this project is a roadmap that helps 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).

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The project aimed to develop a concept for small aircraft to obtain alternative positioning, navigation and timing (APNT) information, when conventional GPS fails, while keeping the performance and efficiency consistent with the airspace requirements. This concept took into account a number of requirements derived from navigation, operational and industry needs as well as SESAR’s vision for future ATM operations (SESAR European ATM Master Plan).
NAVISAS investigated multiple constellation satellite positioning systems with miniature atomic clock (MAC), miniature atomic gyroscope (MAG) and vision-based navigation. The project analyzed several paths for technology mergers for applications in small aircraft navigation, in particular: (i) standalone high grade inertial navigation system (INS) based on atomic gyros, (ii) hybridized multi-constellation multi-frequency system coupled with high grade INS, and (iii) vision-based navigation.

The project established the state of the art in terms of navigation techniques specifically for small A/C 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.

The TRL of NAVISAS atomic gyroscope reached TRL3. Envisioned performances are promising and could challenge currently used high grade laser gyros. Several solutions at the system level have been developed to reduce the price of the entire IMU system combing 3 axis gyros, accelerometers, GPS /GALILEO /GLONASS and atomic clock for application in UAV and ULA.

This project assessed a possibility of hybridization of multi-constellation multi-frequency GNSS coupled with high-grade INS. Regarding multi-frequency receivers, no real benefit could be seen from their use when compared GPS L1 signal, nevertheless they are a good backup mean in case of unintentional interference on one GNSS frequency. Multi-constellation GNSS tight coupling with INS is an interesting approach for scenarios with frequent GNSS outages and is already used in commercial aviation. Purely inertial performance of high-grade INS based on atomic gyros is expected to reach the one from currently used laser gyros. GNSS hybridization with INS-based on atomic gyros achieved TRL3 in this project.

In the scope of this project, real flights have been executed in order to assess vision-based navigation. Performances achieved for UAV and light aircraft were good (only 1 - 2 % drift was demonstrated). This technology is expected to become a standard for UAVs in the coming years. NAVISAS delivered a proof of concept and achieved TRL2 in this matter.

This project delivered 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. The research included extensive literature review on performance based navigation documentation and clarified the relevance of specific PBN aspects to small aircraft operations. Environmental and performance constraints have been identified along with design assurance standards specific to commercial aircraft. These might impact NAVISAS in future exploitation of the project results in commercial aviation. A plan for the integration of this kind of system in aeronautics was proposed and the possible market which is available for the application of this technology was estimated.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Solutions for APNT systems currently under evaluation comprise ground-based infrstructures transmitting non-GNSS signals-in-space to avionics, and can not be used by small aircraft without major engineering of their avionics systems. NAVISAS delivered a concept addressing specifically needs of small aircraft. It integrates multiple-constellations with a novel micro atomic gyroscope and atomic clock.

The proposed APNT concept for small aircraft is expected to impact the navigation reliability and safety and hence the performance, efficiency and safety of the ATM system at many levels.

Multi-constellation approach and receiver coupling with INS improves signal availability and decreases signal recovery time. In the long-run, upon the GNSS loss, IMU quality will dominate the navigation accuracy and expected performances of atomic gyroscope could challenge the state-of-the-art laser ring gyros. The loss of GNSS in manned aircraft, even in VFR, is likely to have a significant Human Factor. INS based on atomic gyros could provide coasting, assuring the RPAS platform (and hence RPAS operator) navigation capabilities. For the pilot of manned aircraft atomic gyro would provide time and comfort to revert to other navigation mean and divert to the nearest airport if needed.

IMU based on the atomic gyroscope is expected to become cheaper in manufacturing, it has a potential to replace current high grade certified inertial systems using expensive laser gyros, because experiments run in the scope of this project showed that NAVISAS solution would meet their performance. This makes the solution more attractive to the manufacturers of commercial aircraft and opens high performance inertia market to new clients.

NAVISAS functional block diagram.

Early NAVISAS building blocks before the inclusion of vision-based navigation.