44TH ANNUAL CONFERENCE, Melbourne, Australia, 17-22 April 2005WP No. 84Review Policy on SurveillancePresented by TOC |
Introduction
1.1. New tools for surveillance of air traffic are being introduced. Discussion is occurring as to what are appropriate applications, requirements and standards for each type of surveillance. In order for these discussions to progress, and so that unambiguous IFATCA policy can be developed, it is essential to have clear definitions of each type of surveillance.
1.2. It has been decided to address several work items on surveillance assigned to TOC last year in this single working paper. The work items are:
a) Produce definition of independent surveillance;
b) Produce definition of dependent surveillance and automatic dependent surveillance;
c) Review manual of surveillance policies; and,
d) Investigate generic surveillance requirements.
Discussion
2.1. Surveillance
2.1.1. Discussions have been limited as there is no commonly agreed definition on surveillance.
2.1.2. Clearly surveillance has been and will continue to be important for Air Traffic Management (ATM). Surveillance is included from the work on Future Air Navigation systems (FANS) in the acronym CNS (Communication, Navigation and Surveillance). However a search of ICAO documents shows no definition for surveillance (or for ATC surveillance) although both terms are used often in ICAO documents.
2.1.3. A definition of surveillance is required as there are some who view surveillance as only covering radar whereas others would accept a broader understanding of surveillance.
2.1.4. The ICAO global air navigation plan accepts the wider understanding. It states:
“The current voice position reporting is a dependent surveillance system in which the position of the aircraft is determined from on-board navigation equipment and then conveyed by the pilot to ATC by radiotelephony”. (ICAO Doc 9750 Chapter 7)
2.1.5. The challenge to terminology and understanding has occurred due to the introduction of Automatic Dependent Surveillance – Broadcast (ADS-B). The high update rate surveillance has been compared to radar and some within ICAO Panels consider that the term Surveillance should now been used to refer to “radar and/or ADS-B (and/or other high update rate electronic surveillance)” – however the S in CNS cannot be limited to just “radar or radar-like”. The ICAO Global Plan also supports this position. Therefore surveillance is more that “radar”.
2.1.6. Another limiting way of viewing surveillance is that surveillance is just position and level information. This is of course is a traditional way of viewing surveillance, for example ICAO define radar as “a radio detection device which provides information on range, azimuth and/or elevation of objects”, that is position and level. However the definition on surveillance must also be applicable to the future. Mode S Secondary Surveillance Radar (SSR) can provide more information, such as Downlink Aircraft Parameters (DAP), and ADS-B supplies more information than just position and level. It is expected therefore that this information will be used in the future and so must be considered when forming a definition on surveillance.
2.1.7. Another way of view surveillance is considering it only from an air traffic control perspective. Already there are applications for collision avoidance systems that use surveillance. Other non-ATC surveillance applications are being developed.
2.1.8. The International Federation of Airline Pilots’ Association (IFALPA) has reviewed its policy on surveillance and is proposing the following definition to its next conference. “Surveillance is the function of an ATC system to acquire information on the relative positions of all aircraft with which it is concerned for the purpose to establish and maintain safe separation between them by adjusting their cleared flight paths.” This is certainly a part of ATC Surveillance. However it is possible to vector an aircraft using radar surveillance when there is only one aircraft, and so a definition more than the relative positions of aircraft is required for IFATCA’s use.
2.1.9. Surveillance is derived from “to watch over” and can be defined in general English use as “close observation or supervision”. This implies more than a single snap shot view and implies an on going activity.
2.1.10. What is required is a general definition of Surveillance as it applies to ATM. Although the definition should be wide and allow for current and future use, we are not interested in surveillance beyond its application for ATM.
2.1.11. The proposed definition for (ATM) Surveillance is:
Surveillance is the acquisition and monitoring of objects’ position, and/or other relevant data for the purpose of Air Traffic Management, such as identity, movement, and intent.
2.1.12. The term object was used as it is the term used in the ICAO definition of radar. Surveillance is more than just aircraft, for example ground vehicles on an aerodrome.
2.1.13. There has been deliberately no mention of the form of surveillance, for example electronic. Visual and even acoustic surveillance would be covered within this definition.
2.1.14. The definition can be applied to airborne surveillance systems.
2.1.15. The definition can be qualified by additional terms as required, for example ATC surveillance, position surveillance, etc. however the normal ICAO practice appears to have separate specific definitions with common items reiterated each time.
2.2. Independent surveillance
2.2.1. Independent surveillance is commonly used to detect violations of controlled airspace.
2.2.2. The proposed definition of independent surveillance is:
Independent surveillance is surveillance that does not depend on any action by the object of surveillance.
2.2.3. Visual surveillance and primary radar surveillance are examples of independent surveillance.
2.3. Dependent surveillance
2.3.1. Although ICAO does not define dependent surveillance, an example of a voice position report is used in the quote used in paragraph 2.1.4.
2.3.2. The proposed definition of dependent surveillance is:
Dependent surveillance is when surveillance data is supplied by the subject of the surveillance.
2.3.3. The proposed definition of Automatic Dependent Surveillance (ADS) is:
Automatic Dependent Surveillance (ADS) is when an electromechanical device, after activation, requires no human involvement to supply dependent surveillance data.
2.3.4. Examples of automatic dependent surveillance include Mode C SSR and ADS-B.
Conclusions
3.1. The lack of clear definitions for surveillance has limited discussion on surveillance. Definitions are required for surveillance types so that IFATCA can progress work on applications, requirements and standards for surveillance tools.
3.2. The introduction of new forms of surveillance has highlighted different understandings of surveillance. Surveillance should be used in it widest sense. It is not just position information, but any information required, for example identification, intentions, speed, etc. It is not just surveillance for ATC but for pilots, electromechanical systems, etc.
Recommendations
It is recommended that;
4.1. The definition of surveillance:
Surveillance is the acquisition and monitoring of objects’ position, and/or other relevant data for the purpose of Air Traffic Management, such as identity, movement, and intent.
be included in the IFATCA Manual page 3 2 6 1.
4.2. The definition of independent surveillance:
Independent surveillance is surveillance that does not depend on any action by the object of surveillance.
be included in the IFATCA Manual page 3 2 6 1.
4.3. The definition of dependent surveillance:
Dependent surveillance is when surveillance data is supplied by the subject of the surveillance.
be included in the IFATCA Manual page 3 2 6 1.
4.4. The definition of Automatic Dependent Surveillance (ADS):
Automatic Dependent Surveillance (ADS) is when an electromechanical device, after activation, requires no human involvement to supply dependent surveillance data.
be included in the IFATCA Manual page 3 2 1 4.
Last Update: September 29, 2020