Heliborne Obstacle Warning Systems

Frequency Spectrum Regulatory Aspects

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The Operational Need

EASA statistic on accidents in commercial air transport (2001-2010)

CTOL – Conventional Take Off and Landing

• IHST goal: reduction of helicopter accident rate in 10 years by 80%

• 2007: 8,7 per 100 000 flight hours

• 2016: < 1,7 per 100 000 flight hours

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The Operational Need

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Take Off of Emergency Medical Service Helicopter in confined area

Helicopter Missions: Emergency Medical Service

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Helicopter Crews risk their life every day to safe the life of others

Landing in unprepared / unknown areas

Landing/takeoff in confined areas

Hoisting operations near rock face / obstacles

For all these missions obstacles and terrain are a

permanent threat to the helicopter crew

Flight in Degraded Visual Environment

The Operational Need

Obstacle collision during landing/take-off is the Nr.1 cause for

commercial air transport accidents *

Operational need for an obstacle warning system to support our civil

customers in:

► Increasing Situational Awareness

► Reducing Pilot Workload

► Increasing Flight Safety

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* EASA Annual Safety Review 2010

The Challenge

Modern day Obstacle Warning Systems (OWS)

• Complex (~expensive) solutions

• Mainly military applications

• Not affordable for civil operators (limited budget,

different platforms)

Challenge is to develop an OWS system affordable for civil customers.

Affordable in terms of:

• Price

• Size, Weight and Power (SWaP)

Proposal

To apply COTS radar technology being developed in automotive industry

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Laser

OWS on

NH90

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Targeted Civil Use Cases

HEMS – Helicopter Emergency Medical Services

• Outdoor landings

• Hoisting operations

• Landing at sloped terrain

Offshore Operations

• Landing at shipdeck or oil rig

• Windpark maintenance

Utility & Transport

• Forestry

• Firefighting (sling load operations)

• Powerline inspection

Market volume

• Global Eurocopter Fleet: 11 500 Helicopters

with 3,2 Million Flight Hours/Year

• Civil Helicopter Fleet in Germany: 800 Helicopters

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Heliborne Obstacle Detection

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Function Requirements dependent on Flight Phase (Use Case)

Approach/landing/takeoff • Low airspeed operations → limited detection range

• Operations at low altitude

• Surround view, hemispherical coverage

• Obstacles: all obstacles e.g. trees, bushes, fence, poles,

buildings

Hover • Hover operations → limited detection range

• Operations in ground vicinity

• Covering rotor disc & tail rotor area only

• Obstacles: all obstacles eg. trees, bushes, fence, poles,

buildings etc.

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Patent Pending

SITA Near Field OWS System Description

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Intended Function

• Increase flight safety in most critical phases of flight i.e. during

approach, landing and take-off phases of flight

Key Requirements

• Hemispherical coverage

• All weather obstacle detection

• Low SWaP

• Affordable for civil operators

• Modular and scaleable system design

Use Cases

• Landing in unprepared / unknown areas

• Landing/takeoff in confined areas

• Landing/takeoff in degraded visual conditions

Patent Applied

SITA Near Field OWS System Design

System Design

• Distributed sensor system for hemispherical coverage

• Use of automotive radar technology (FMCW)

• Advanced filtering and processing algorithms

• Intuitive HMI concept

• Max detection range ~250m (10s warning time at 45kts)

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Sensor prototype on EC145 test bed

Patent Applied

SITA Near Field OWS Sensor Description

SITA Sensor

• FMCW-Radar with digital beamforming on receive

• Frequency Range 76.0-76.1 / 78.9-79 GHz

(dual band operation for vertical beamsteering)

• Modulation: interrupted fast ramp FMCW

(modulation period typ. 20 µs, Bandwidth typ. 100 MHz)

• Transmit-Power: 35 dBm EIRP

• FoV: 75° horizontal, 5°- vertical (electronic steerable)

• Broad Transmit-Beam, narrow digitally formed receive beam

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RF Frontend 16 Rx, 2Tx

Tx-Antenna pattern vertical (steerable) Tx-Antenna pattern horizontal

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Patent Applied

RSAS Rotor Strike Alerting System System Description

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Intended Function

• To prevent main and tail rotorstrike by informing the pilot of

obstacles in the main and tail rotor area of the helicopter.

Key Requirements

• Coverage of main rotordisc and tail rotor area

• All weather obstacle detection

• Low SWaP

• Affordable for civil operators

Use Cases

• Landing and Takeoff phase

• Hover in confined areas (e.g. hoisting operations)

• Slope landings

Patent Applied

RSAS Rotor Strike Alerting System System Design

System Design

• Distributed sensor system (4 sensors)

• Use of automotive radar sensor (77GHz SRR)

• Limited detection range

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Patent Applied

RSAS Rotor Strike Alerting System Sensor Description

Radar Sensor

• Radar based on automotive short range obstacle detection system

• FMCW-Radar with digital beamforming on receive

• Frequency Range 76.0 – 77 GHz

• Modulation: interrupted fast ramp FMCW

(modulation period typ. 40 µs, bandwidth up to 800 MHz)

• Transmit-Power: 21 dBm EIRP

• FoV: +/- 50° horizontal, 10° vertical

• Broad Transmit-Beam, narrow digitally formed receive beam

• Detection Range: up to 40 m, up to 100 m (Dual Mode Operation)

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Patent Applied

Summary

There is a need for an affordable obstacle warning function to increase flight

safety for civil operators

Commercial Off-The-Shelf radar technology is proven to be the key to:

• Improve safety of the helicopter aircrews, passengers and people on the

ground

• In a wide range of missions supporting public safety (EMS, Police etc.)

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W-Band technology to save lives

in airborne applications