1、二次雷达（二次雷达（SSR）中国民航大学中国民航大学电子信息与自动化学院电子信息与自动化学院电子信息与自动化学院二次雷达（SSR）outlineoutline1.1. SSR introductionSSR introduction2.2. MODE A/CMODE A/C3.3. MODE SMODE S2电子信息与自动化学院二次雷达（SSR）outlineoutline1.1. SSR introductionSSR introduction2.2. MODE A/CMODE A/C3.3. MODE SMODE S3电子信息与自动化学院二次雷达（SSR）Limitations of PS
2、R (Why we need SSR?)v Targets that are too Targets that are too small, or are built of a small, or are built of a poor radar reflecting poor radar reflecting material or have a poor material or have a poor aspect may not be aspect may not be detecteddetectedv Targets cannot be Targets cannot be iden
3、tified directly (IFF identified directly (IFF in the WW2)in the WW2)v Radar energy suffers from Radar energy suffers from attenuation (losses) both attenuation (losses) both on the path out to the on the path out to the target and on the return target and on the return path of the reflectionspath of
4、 the reflectionsv The role of the SSR is to The role of the SSR is to complement the PSRcomplement the PSR4电子信息与自动化学院二次雷达（SSR）Radar AntennaGround Radar DisplayTransmitter Receiver电子信息与自动化学院二次雷达（SSR）Radar AntennaGround Radar DisplayTransmitter ReceiverMode A/C XPDR电子信息与自动化学院二次雷达（SSR）Interrogation Rep
5、lyA/C IdentificationFlight LevelRadar AntennaGround Radar DisplayTransmitter Receiver电子信息与自动化学院二次雷达（SSR）SSR：Secondary Surveillance RadarSSR is a radar system used in ATC/CNS that not only detects and measures the position of aircraft i.e. range and bearing, but also requests additional information f
6、rom the aircraft itself such as its identity and altitude. Unlike primary radar systems that measure only the range and bearing of targets by detecting reflected radio signals, SSR relies on targets equipped with a radar transponder, that replies to each interrogation signal by transmitting a respon
7、se containing encoded data. SSR is based on the military identification friend or foe (IFF) technology originally developed during World War II, therefore the two systems are still compatible. Monopulse secondary surveillance radar (MSSR), TCAS and ADS-B are similar modern methods of secondary surve
8、illance. 8电子信息与自动化学院二次雷达（SSR）PSR vs SSRPSR vs SSR9电子信息与自动化学院二次雷达（SSR）SSRSSR antennaantenna10电子信息与自动化学院二次雷达（SSR）SSR characters v SSR is not a true radar system but a two way communications system between an interrogator on the ground and a transponder on the aircraft. v However SSR is very similar in
9、 operation to conventional radar and suffers from many of the same problems and limitations.v Most commercial aircraft are required to be fitted with this equipment for transit through controlled airspace. 11电子信息与自动化学院二次雷达（SSR）电子信息与自动化学院二次雷达（SSR）Operation of a Secondary RadarOperation of a Secondary
10、 Radar13电子信息与自动化学院二次雷达（SSR）Slant range measurementSlant range measurement14电子信息与自动化学院二次雷达（SSR）Radar equationRadar equation15电子信息与自动化学院二次雷达（SSR）characterscharacters16Uplink:Radar transmission power in Watts: 1600 W 62 dBmRotation speed: 4 to 8 sec/trInterrogation repetition frequency : 250 Hz (use of
11、 ACID received from Mode S repliesvFlight number = ACID delivered to the controller for identification instead of Mode A127电子信息与自动化学院二次雷达（SSR）Instruments installed in an AircraftInstruments installed in an Aircraft128电子信息与自动化学院二次雷达（SSR）Questions ?Questions ?1291 In order to receive secondary informa
12、tion, aircraft and radar site must be equipped with what?2 What is depicted on the radar display, call sign or squawk code?3 What are the two basic functions of radar?4 TRACON stands for what?5 TRACON uses ASR to provide service in which phase of fight and in what radius of an airport?6 How centers are able to cover hundreds square miles with a single sector?
