Radar Cross Section
Radar Cross Section Definition
Radar cross section expresses the detectability of an object by radar. The more this amount, the object is more radar visible. An object returns a limited amount of radar energy. The magnitude of electromagnetic waves return to its source is determined by a variety of factors, including:
- The material from which it was made
- Target accurate size
- The angle of attack (the angle of radar waves when hit a particular part of the target, depending on the target's shape and direction of the radar source).
- The target size ratio to the wavelength generated by the radar
- The polarization of the waves is sent and returned according to the direction of the target
Standard RCS Measurement Requirements
According to the standard used in this laboratory, the facility used to validate RCS values should be able to measure the RCS values, which are 10 to 20 dB below the lowest radiation level, so that they can detect the entire radar cross-section of the object. This feature may be available with experience and skill, in which case the tests should be performed accurately and repeatedly. Common questions that can be raised include "How is the range of RCS testing accurately determined?", "How close is the precise value of RCS to the measured value?", "How is the exact amount determined?", "How much does it cost?", "How much is it necessary to repeat values close to real value?" These questions and other questions for the development of standards or standardization operations are precisely determined.
Determine the range of measurement
The purpose of the test range is to provide an environment for simulating the conditions of the far field or free space. RCS of objects that fall into this environment can be measured by precision instrument radars with high accuracy.
Measurement RCS Near Field and Far Field
The RCS test range for Antenna, Ridome and RCS measurements is designed under plate wave conditions. Setup test of targets radar cross section measurements, is direct method. Given that the possibility of direct radiation causes real-time measurements to be provided for frequencies below 2GHz, it is possible for errors to occur for low frequencies.
The presence of a controller unit with a precision of 1 degree guarantees a high precision measurement. The antenna is placed on a rotor in order to easily change the polarization. To measure radar cross section, a plastic axis with absorber foam can be used to minimize the effect of unwanted wave propagation and to ensure the accuracy of measurement.
Ease of Information Control
In the process of data processing after measurement, the existence of a graphical analysis tool offers a lot of options. The existence of a dual computer system near the antenna room allows the learning and processing operations to take place simultaneously.
Network Analyzer hp 8720C is used to transmit and receive signals. The fast sweep time and Measurement speed for each test indicate the system's ability to run. A powerful linear positioning device with a precision of 1 degree is designed to change the antennas position relative to the target. Also, the use of a rotating table with 1 degree ratation capability provides the possibility of swipe for the target. Given the importance of wave radiation to the target, the use of adjustable stands makes test more accurate for measurement.