In the RADAR data acquisition system, the COTAL RADAR data is processed by a microprocessor 8085 and the processed data is first sent to the RADAR control room and transferred to the main control room by means of a MODEM At a baud rate of 9600bps, the encoded data is decoded by the INTEL 8051 microcontroller. The microcontroller kit is equipped with a serial data transmission / reception system. The RS 232 format is converted to TTL format by RS232 IC's converter.
The data acquisition program resides in the Instructor Kit EPROM. Data relating to the RANGE, AZIMUTH, ELEVATION & QUALITY information is separated and fed to the DISPLAY system via the I / O peripheral interface IC 8255. The QUALITY information is taken directly from port 0 of 8051 and via a circuit Interface the operating mode (Automatic / manual) and the quality of the data received.
Radar is an electromagnetic system for detecting and locating objects. It operates by transmitting a particular type of waveform, a pulse-modulated sine wave, for example, and detects the nature of the echo signal.
Radar is used to extend the ability of the senses to observe the environment, especially the sense of vision. In addition, radar has the advantage of being able to measure the distance or reach to the object. Radar is a contraction of the words "Radio Detection And Ranging". An elementary form of radar consists of a transmitting antenna that emits electromagnetic radiations generated by an oscillator of some sort, a receiving antenna and an energy detection device or receiver. A part of the transmission signal is intercepted by a reflecting object (target) and redirected in all directions.
The receiving antenna collects the energy returned and delivery to the receiver, where it is processed to detect the presence of the target and extract its location and relative velocity. The distance to the target is determined by measuring the time it takes for the radar signal to move towards the target and vice versa.
The direction or angular position of the target can be determined from the direction of arrival of the reflected wavefront. The usual method of measuring the direction of arrival is with a narrow antenna beam. If there is relative movement between the target and the radar, the displacement of the carrier frequency of the reflected wave (Doppler effect) is a measure of the relative velocity of the targets and can be used to distinguish moving targets from stationary. In radars that continuously control the movement of a target, a continuous indication of the rate of change of the target position is also available.
The most common radar waveform is a narrow and rectangular pulse train that modulates a sine wave carrier. The distance or reach to the target is determined by measuring the TR time taken by the pulse to travel to the target and return. Since electromagnetic energy propagates at the speed of light C = 3 x 10 8 m / s the R = CTR / 2 range. Factor 2 appears in the denominator due to bidirectional radar propagation, with the range in kilometers And TR Nanoseconds R (km) = 0.15TR (microseconds).
Once the transmitted pulse is emitted by the radar, sufficient time must elapse to allow any echo signal to return and be detected, before the next pulse can be transmitted. Therefore, the rate at which pulses can be transmitted is determined by the longer interval at which targets are expected. If the pulse repetition frequency is high, the echo signals from some targets may arrive after the transmission of the next pulse and ambiguities may occur in the measurement range.