SATELLITE AND RADAR SYSTEM (NEC-045)
According to the uploaded question paper
The Satellite and Radar System examination is divided into three sections: A, B, and C. The structure of the paper is designed to assess fundamental radar and satellite concepts first, then move toward mathematical derivations and system-level analysis, and finally test advanced applications and numerical reasoning.
Below is a detailed explanation of each section in clear and descriptive format.
Section A – Fundamental Concepts of Radar and Satellite Systems (20 Marks)
Section A consists of ten compulsory short-answer questions, each carrying two marks. This section evaluates your understanding of the basic terminology and fundamental principles used in radar and satellite communication systems.
The questions include topics such as applications of radar, antenna scanning, maximum unambiguous range, false alarm, Doppler effect, advantages of geostationary satellites, azimuth angle, apogee and perigee, ascending and descending nodes, and the meaning of ODU (Outdoor Unit) and IDU (Indoor Unit).
Although the answers are short, they require conceptual clarity. For example, when explaining maximum unambiguous range, you should mention that it is the maximum distance at which a radar can detect a target without range ambiguity, determined by pulse repetition frequency. Similarly, Doppler effect should be explained as the change in frequency due to relative motion between radar and target.
This section ensures that you understand the fundamental building blocks required for advanced radar and satellite analysis.
Section B – Theoretical Derivations and Orbital Mechanics (30 Marks)
Section B requires you to attempt any three questions, each carrying ten marks. This section focuses on mathematical derivations, signal parameters, and orbital mechanics.
The questions include the basic principle of radar along with derivation of the radar range equation, definitions of pulse width, pulse repetition time, average power, duty cycle, and missed detection, system losses in radar, Kepler’s laws of planetary motion and their relevance to satellites, and orbital elements of satellite systems.
In this section, you are expected to provide detailed explanations supported by mathematical expressions and diagrams. For example, when deriving the radar range equation, you must explain transmitted power, antenna gain, radar cross-section, and losses affecting received power. When discussing Kepler’s laws, you should explain how satellites follow elliptical orbits and how orbital period relates to semi-major axis.
This section tests your understanding of radar performance analysis and satellite orbital dynamics.
Section C – Advanced Radar Processing and Satellite Communication Systems (50 Marks)
Section C carries the highest weightage and requires you to attempt one part from each question. This section tests your advanced knowledge of radar signal processing and satellite communication systems.
Topics include Continuous Wave (CW) radar with block diagram, delay line cancellers, sequential lobing technique, radar range modification problems, digital MTI Doppler signal processor, satellite communication elements, telemetry tracking and command systems, look angle calculation, GPS segments and signal acquisition, and Direct Broadcast Satellite (DBS) television systems.
For example, the numerical radar range problem requires understanding that radar range is proportional to the fourth root of transmitted power, antenna gain, effective aperture, and wavelength relationships. Any change in these parameters directly affects maximum range. Similarly, when explaining digital MTI, you must describe how Doppler processing is used to distinguish moving targets from stationary clutter.
When discussing GPS, you should explain its three main segments: space segment, control segment, and user segment, along with the process of satellite signal acquisition.
This section evaluates your analytical ability, system-level understanding, and ability to
connect theoretical radar equations with practical communication systems.
Overall Paper Structure and Preparation Strategy
The paper is structured progressively. Section A tests conceptual clarity. Section B evaluates derivation skills and understanding of orbital and radar equations. Section C focuses on signal processing, satellite communication systems, and numerical applications.
To perform well:
Understand radar fundamentals and key definitions clearly.
Practice derivation of radar range equation.
Study Kepler’s laws and orbital elements carefully.
Learn block diagrams of CW radar, MTI radar, and satellite communication systems.
Practice numerical problems involving radar range and look angle calculations.
