Mode S Elementary & Enhanced Surveillance (EHS and ELS)
Mode S and Secondary Surveillance Radar - Whilst traditional Secondary Surveillance Radar (SSR) stations interrogate all aircraft within their range, Mode S establishes selective and addressed interrogations with aircraft within its coverage.
Such selective interrogation improves the quality and integrity of the detection, identification and altitude reporting. These improvements translate into benefits in terms of safety, capacity and efficiency. This first step of selective interrogation is known as Mode S Elementary Surveillance (ELS).Mode S Enhanced Surveillance (EHS) builds upon the concept of Elementary Surveillance and consists of the extraction of further aircraft parameters known as Downlink Airborne Parameters (DAPs). The additional DAPs include:
- Selected Altitude
- Roll Angle
- Track Angle Rate (or True Airspeed if Track Angle Rate is not available)
- True Track Angle
- Ground Speed
- Magnetic Heading
- Indicated Airspeed/Mach No.
- Vertical Rate (Barometric rate of climb/descend or baro-inertial)
An aircraft is considered to be EHS capable if the above 8 DAPs can be supplied.Not all aircraft are EHS capable, The Eurocontrol website gives some useful information regarding aircraft that are and are not EHS capable.
Your Requirement?
If you require EHS or ELS for your aircraft, please don't hesitate to contact FlitePartners Ltd for initial discussion or complete our online proposal form and we will be in touch shortly.
Further Reading:
Eurocontrol Mode S