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presentation On Secondary RADAR Presented By: 1 6/28/2011 Civil Aviation Authority Shahjahan Jabbar Memon M.Naveed Shaikh

### Presentation during internship at caa pakistan:

Presentation during internship at caa pakistan By: Engr . Shahjahan Jabbar Memon Engr. M.Naveed Shaikh Department of Telecommunication Engineering Mehran University Of Engineering & Technology Jamshoro , Sindh, Pakistan. Contact Email: shan_memon007@yahoo.com shahjahan.memon08tl81@student.muet.edu.pk 2 6/28/2011 “The journey of a thousand miles begins with one step.”

### Introduction :

Introduction RADAR is acronym for RAdio Detection And R anging. Radar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction or speed of both moving as well as static objects, such as Aircrafts, Ships, Weather, Motor Vehicles. 3 6/28/2011

### Working principle AND some components:

Working principle AND some components The actual range of a target from the radar is known as slant range. Slant range is the line of sight distance between the radar and the object illuminated. G round range is the horizontal distance between the emitter and its target and its calculation requires knowledge of the target's elevation. Since the waves travel to a target and back, the round trip time is dividing by two in order to obtain the time the wave took to reach the target. 4 6/28/2011

### Formula:

Formula Therefore the following formula arises for the slant range: where: c 0 = speed of light = 3·10 8 m / s t = measured running time [s] R = slant range antenna - aim [m] The distances are expressed in kilometers or nautical miles (1 NM = 1.852 km). 5 6/28/2011

### View of radar transmission and reception:

View of radar transmission and reception 6 6/28/2011

### Simple Diagram:

Simple Diagram 8 6/28/2011

### Display:

Display Also known as plan position indicator (PPI), radar scope, or scope Main bang Sweep Echo, target, or blip Radar cross-section Ground clutter 9 6/28/2011

Different Displays of radar 10 6/28/2011

### Definitions of basic terms on display:

Definitions of basic terms on display Echo: The desired signal is called Echo. When the signal is reflected from the target and appears on the Radar display, then that signal is called Echo. Clutter: The undesired signal is called Clutter. When the signal is reflected from the undesired objects (Mountains, Birds etc.) then the appearance of that signal on the radar display is known as Clutter. Noise: The internal or thermal noise signal of Radar can be appeared on the Radar display if the threshold level for display is set at low level, therefore threshold level should be maintained according to the conditions. 11 6/28/2011

Secondary radar A secondary radar system is a cooperative target identification system in which the interrogator transmits an encoded signal to a target. The signal transmitted by the secondary radar is intercepted and received by the target. The target has a transponder on board that interprets the encoded signal and transmits an encoded reply back to the interrogator. The secondary radar system receives and interprets the target's encoded signal. 13 DEFINITION 6/28/2011

### Two important parts of secondary radar:

Two important parts of secondary radar There are two important parts of SSR Ground Interrogator Air Craft Transponder 15 6/28/2011

### Ground interrogator:

Ground interrogator The secondary radar unit needs a synchronous impulse of the (analogous) primary radar unit to the synchronization of the indication. The chosen mode is encoded in the Coder. (By the different modes different questions can be defined to the airplane.) The transmitter modulates these impulses with the RF frequency. Because another frequency than on the replay path is used on the interrogation path, an expensive duplexer can be renounced. The antenna is usually mounted on the antenna of the primary radar unit and turns synchronously to the deflection on the monitor therefore. 16 6/28/2011

### Air craft transponder:

Air craft transponder A receiving antenna and a transponder are in the airplane. The receiver amplifies and demodulates the interrogation impulses. The decoder decodes the question according to the desired information and induces the coder to prepare the suitable answer. The coder encodes the answer. The transmitter amplifies the replay impulses and modulates these with the RF reply-frequency. 17 6/28/2011

### Again in the interrogator :

Again in the interrogator The receiver amplifies and demodulates the replay impulses. Jamming or interfering signals are filtered out as well as possible at this. From the information „Mode ” and „Code” the decoder decodes the answer. The monitor of the primary radar represents the additional interrogator information. Perhaps additional numbers must be shown on an extra display. 18 6/28/2011

Advantages of ssr It provide co operative mean of target identification. It provides IFF(Identification of friend or Foe). Transponder provides information like aircraft origin, destination and flight numbers. These information can not be acquired from a primary Radar. 20 6/28/2011

### Components of ATCRBS:

Components of ATCRBS Two secondary radar antennas One is physically located on top of primary antenna, rotating with it Another reference antenna is fixed next to rotating antenna 21 6/28/2011

### PowerPoint Presentation:

Rotating Antenna SLS Antenna 22 Pictorial view 6/28/2011

### Side Lobe Suppression:

Side Lobe Suppression 23 6/28/2011

### Secondary Radar Unable to Automatically Identify Targets:

Without an automation system, controllers still have to use "shrimp boats" to identify and track each target on the radar display Secondary Radar Unable to Automatically Identify Targets Solution: automate ATCRBS by using computerized systems 24 6/28/2011

### Number of Radars in pakistan:

Primary Radar: There are 3 primary radar in Pakistan i-e: One at Islamabad, One at Lahore, One at Karachi. Secondary Radar: There are six secondary radar in Pakistan i-e: One at Islamabad, One at Lahore, One at Karachi, One at Rojhan , One at Lakpas , One at Pasni . Number of Radars in pakistan 25 6/28/2011

### Radar coverage area in pakistan:

Radar coverage area in pakistan 26 6/28/2011

### Difference B/w Secondary & Primary RADAR:

Difference B/w Secondary & Primary RADAR In primary radar ,energy generates only at single point i-e at radar itself. In secondary radar, energy generates at both ends in radar interrogator and transponder of aircraft. 27 6/28/2011