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High Stability Vertical Separation Altimeter Instruments

Tags: Air

State of the Art - Background

HISVESTA is the next step in solving the remaining research and technological development challenges after the successful HASTAC project in the EC Framework Programme Six ( The project will develop a new generation of barometric altimetry modules, suitable for fixed-wing and helicopter applications, which will provide significantly improved capabilities for altitude accuracy. Altitude transducers, air data computers and meteorological testing performed in the project will demonstrate the effectiveness of the performance improvement.

A key HISVESTA target is for the European avionic system industry to regain the market lead in altimetry and automatic air traffic control (ATC) solutions, as well as to manufacture altitude pressure transducers with the best long-term stability.


The strategic objective of the project is to increase the safety in all in-flight situations, particularly in low visibility, by improving the barometric altimetry transducers used in air data computers and auto pilot systems for aircraft. The project is particularly relevant in situations in the reduced vertical separation minima legislation of 1 000ft (RVSM), as well as in demanding manual flying situations such as darkness and low visibility. Used in enhanced transponder applications, the project will contribute to significantly increased reliability in altitude information for manual and automated air traffic control systems. Aircraft Traffic Collision Avoidance Systems will also benefit from more accurate and reliable altitude information, which will allow the automated avoidance instructions to be more accurate and effective.

Another project objective is to contribute towards reducing CO2 and NOx emissions in the next generation aero engines, by improving accuracy in the multifunctional pressure control system in the Full Authority Digital Engine Control systems (FADECS). The HISVESTA project will develop a range of high temperature micro-machined silicon structure (MEMS) pressure sensors, designed for accurate pressure measurements in multistage FADECS.

Description of Work

The main concept is to create a new state-of-the-art high precision altimetry sensor system that monitors the aircraft barometric altitude in real time with a very high accuracy. This will be done based on new technology in MEMS and new concepts using microcontrollers and FPGAs for compensation and warning algorithms.

The project will develop new generations of altimetry modules, suitable for fixed wing and helicopter applications, which will provide a significant improvement in altitude and pressure reading accuracy over those currently available. Comprehensive modelling, analysis, lab testing and flight data collection performed in the project will demonstrate the effectiveness of the performance improvement.

The altimetry transducer long-term drift goal is <0.01 %FS/year, which will increase altitude accuracy by a factor 2 and will allow longer calibration intervals of the entire system. The root causes for long-term drift will be determined by modelling and detailed statistical characterisation and analysis. Resulting effects of these causes will be minimised by careful co-design of the MEMS sensor element, fabrication processes, pressure sensor package, electronics and software. The final result is a new range of barometric pressure transducers optimised for superb stability, accuracy and repeatability.

Expected Results

HISVESTA's goals will contribute to the promotion of real progress, based on scientific and technical excellence and long-term innovation due to:

- Barometric MEMS sensor technology in silicon;

- Unique hardware/software compensation techniques;

- Instruments and air data computer systems;

- Technologies to enable a full and permanent automatic approach and landing in all weathers;

- Onboard technologies for in-flight collision avoidance concepts;

- Techniques enabling the development of improved aviation safety metrics.

Pressure transducer with manifold for FADEC, air data and cabin pressure controller
Pressure transducer with manifold for FADEC, air data and cabin pressure controller

Pressure transducers in MEMS technology
Pressure transducers in MEMS technology