Chương 3: Radar Mode-S pdf

Trường Đại học Bách Khoa Hà Nội
Hanoi University of Science and Technology
© HUST 2012

Hệ thông Thông tin Hàng Không
TS. Đỗ Trọng Tuấn
Bộ môn Kỹ thuật thông tin
Trường Đại học Bách Khoa Hà Nội
Hanoi University of Science and Technology
Radar Mode-S
Chương 3
© HUST 2012

Hệ thống Thông tin Hàng Không
Teminologies
3
Radar: Radio Detection and Ranging
SSR: Secondary Surveillance Radar
Aeronautical Telecommunication (ATN)
Network Environment
ATN ROUTER
ATN ROUTER ATN ROUTER
Avionics Subnetwork
Mode S Subnetwork HF Subnetwork Satellite Subnetwork VHF Subnetwork
CAA Ground
Subnetwork
Management
Processor
ATN End System
Aeronautical
Operations

Data Base
ATN End System
Data Display
Processor
ATN End System
Data Entry
Processor
ATN End System
Management
Processor
ATN End System
Aeronautical
Operations
Control
ATN End System
Weather
Data Base
ATN End System
ATC
ATN End System
FIS
Data Base
ATN End System
Weather
Data Base
ATN End System
Service Provider
Ground Subnetwork
Airline Ground
Subnetwork

Primary Radar
Secondary Surveillance Radar
Primary radar relies on passive reflection
Secondary radar co-located with primary
SSR beam interrogates transponders
Transponder reply depends on its mode
ATC computers use SSR to tag primary echoes
with identifier and height
Secondary Surveillance Radar
interrogation
reply
Secondary Surveillance Radar
Transponders
 A transponder is a receiver / transmitter device designed to
transmit a response signal when legitimately interrogated.
[NATO definition]
 An automatic device that transmits a predetermined
message in response to a predefined received signal.
[Wikipedia]
SSR Principle
P1 P2
P1-P3 spacing
P3
Amplitude
(Interrogation message)
F1
Reponse mesasge
Amplitude
F2
t

P1-P3 spacing Request Modes
8 μs
21 μs
Identify 3/A
Height ?
C
0-2047
4096 codes
Step=
100 feet
Source: understanding radar systems
 Mode A (simple system):
 Aircraft identification (Call-sign)
 Mode C (more advanced):
 Mode A + altitude
 Mode S (more recently):
 Mode C + 24 bit address identifier (unambiguous)
 Provides limited air-air and air-ground communications
 Can also provides whereabouts of other aircraft in its vicinity
 Uses digital error-correcting codes for improved reliability
Allocation of 24-Bit Aircraft address to Vietnam:
1000 10 001 xxx xx xxxxxxxxxx
Secondary Surveillance Radar
ground
station
aircraft 1
aircraft 2
INTERFERENCE!!!
Sidelobe suppression
P2

ground
station
aircraft 1
aircraft 2
P1 P2
A2
P2 P1
A1
Sidelobe suppression
Sidelobe suppression
9 dB
P1-P3 spacing Request Modes
8 μs
21 μs
Identify 3/A
Height ?
C
Mode S
Amplitude
(Source:
Radar mode S
Mode S
Secondary Radar
Primary Radar
Secondary Radar
Primary Radar
Airport Surveillance Radar (ASR) Air Route Surveillance Radar (ARSR)
AWACS: Airborne Early Warning and Control System
Identification Friend or Foe (IFF)
Radar mode S

Trường Đại học Bách Khoa Hà Nội
Hanoi University of Science and Technology