How do you calculate pulse compression ratio?
The pulse compression ratio, which is the duration of the long pulse divided by the duration of the short (compressed) pulse, is equal to BT.
How is radar range of resolution calculated?
Range resolution as a distance can be calculated as follows: Rres = c * τ /2 Where, τ is the transmitted pulse width and c is the velocity of light in the free space. Narrower beamwidth is very useful to distinguish two adjacent targets.
What is range compression in radar?
Pulse compression is a signal processing technique commonly used by radar, sonar and echography to increase the range resolution as well as the signal to noise ratio. This is achieved by modulating the transmitted pulse and then correlating the received signal with the transmitted pulse.
What is the radar equation?
The radar range equation represents the physical dependences of the transmit power, which is the wave propagation up to the receiving of the echo signals. At the known sensibility of the radar receiver, the radar equation determines the achieved by a given radar theoretically maximum range.
What is Barker code in radar?
Barker codes are binary numbers using two to 13 bits and have unique auto-correlation functions. The points adjacent to the peak of the correlation function equal zero. This is very useful in a radar system since any spurious response can be misinterpreted as a target.
Why do radars use chirps?
Hyperbolic chirps are used in radar applications, as they show maximum matched filter response after being distorted by the Doppler effect.
Which factor determines the range resolution of radar?
Pulse width
Pulse width is the primary factor in range resolution. A well-designed radar system can distinguish targets separated by one-half the pulse-width time (τ).
What is ground range resolution?
Ground range resolution (Rr) is the horizontal expression of the slant range resolution (top) and is expressed mathematically as: Rr=cT ÷ 2cos d , where: c = the speed of light (300,000,000 m/s) T = pulse duration. d= depression angle (complement of the “look angle”)
What is the difference in operation between a pulse radar and a pulse compression radar?
Pulse compression is a method for improving the range resolution of pulse radar. Pulse compression combines the energetic advantages of very long pulses with the advantages of very short pulses. The range resolution of a simple pulse-modulated radar depends on the pulse duration.
What is radar frequency range?
Most radars, in practice, operate between 400 MHz to 36 GHz; however, there are some notable exceptions. The optical and radio portions of the electromagnetic spectrum occupy positions coincidental with two important transparent bands in the Earth’s atmosphere and ionosphere.
What is pulse radar system?
A pulse-Doppler radar is a radar system that determines the range to a target using pulse-timing techniques, and uses the Doppler effect of the returned signal to determine the target object’s velocity. Pulse-Doppler systems were first widely used on fighter aircraft starting in the 1960s.
What is Barker codes and write its purpose?
A barker code is one of the possibilities for intra-pulse biphase modulation for pulse compression radar equipment to improve range resolution for relatively long transmission pulses. They are sequences of numbers of different lengths of +1 and −1, which meet the condition of autocorrelation as perfect as possible.
What is the advantage of pulse compression in radar?
Pulse Compression Gain With the help of pulse compression, a relatively long transmission pulse with comparatively low peak power can achieve a better, longer range than the basic radar equation would suggest. This is because pulse compression can still detect echo signals that have already disappeared in the noise before pulse compression.
What is the basic range equation for radar?
2.2 BASIC RADAR RANGE EQUATION One form of the basic radar range equation is 2 3 4 40 S T T R N n P P G G SNR P R kT BF L (2-1) where SNRis termed the signal-to-noise ratio and has the units of watts/watt, or w/w. P S is the signal power at some point in the radar receiver – usually at the output of the matched filter or the signal processor.
What is the range resolution of a pulse-modulated radar?
The range resolution of a simple pulse-modulated radar depends on the pulse duration. Two reflective objects located within the spatial extent of the pulse are only displayed as one target. To improve the range resolution for a relatively long transmission pulse duration, the transmission pulse is modulated internally.
What is the pulse compression ratio?
The pulse compression ratio is sometimes also called Pulse Compression Factor K , because it is entered directly as a factor in the radar equation under the fourth root: However, this requires a largely lossless pulse compression, which can never be achieved in practice.