Target Tracking using Doppler radar
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Abstract Radar stands for radio detection and ranging. It operates by radiating electromagnetic waves and detecting the echo returned from the targets. The nature of an echo signal provides information about the target range, direction, and velocity. Although radar cannot reorganize the collar of the object and resolve the detailed features of the target like the human eye, it can see through darkness, fog and rain, and over a much longer range. It can also measure the range, direction, and velocity of the target. Basic radar consists of a transmitter, a receiver, and a transmitting and receiving antenna. A very small portion of the transmitted energy is intercepted and reflected by the target. A part of the reflection is reradiated back to the radar (this is called back-reradiating). The back-reradiating is received by the radar, amplified, and processed. The range to the target is found from the time it takes for the transmitted signal to travel to the target and back. The direction or angular position of the target is determined by the arrival angle of the returned signal. A directive antenna with a narrow beamwidth is generally used to find the direction. The relative motion of the target can be determined from the Doppler shift in the carrier frequency of the returned signal. Although the basic concept is fairly simple, the actual implementation of radar could be complicated in order to obtain the information in a complex environment.This project use pulse Doppler radar to track target (determine the target velocity and distance), the main technology of this project is Doppler Effect (A change in the observed frequency of a wave, as electromagnetics, occurring when the source and observer are in motion relative to each other, with the frequency increasing when the source and observer approach each other and decreasing when they move apart. The motion of the source causes a real shift in frequency of the wave, while the motion of the observer produces only an apparent shift in frequency). The second technology is power receive, the value of power determine the target distance (power receive proportional to distance) The radar equation provides the received power level as function of the characteristics of the system, the target and the environment. Where Pr is the received power, Pt is the transmitted power, Aer and Aet are the effective area of the receive and transmit antennas, respectively,R is the distance to the target, is the radar cross-section (RCS), defined as the ratio of the scattered power in a given direction to the incident power density and Lsys is the system loss due to misalignment, antenna pattern loss, polarization mismatch, atmospheric loss . Taking into consideration that the effective area of the receive and transmit antenna is related to the wavelength and to the antenna gain Gr and Gt, as Aer=Gr2/4 and Aet=Gt2/4. Based on the system characteristics and the noise floor of the receiver a certain minimal signal power level Pr, min is required in order to detect the target.Furthermore, in most practical designs a minimal signal to noise ratio (SNR) at the output of the receiver SNRo,minis considered in order to ensure high probability of detection and low false-alarm rate. Typically, SNR values of higher than 12 dB are required. Where Si and So are the input and output signal levels, respectively, Noise the noise level at the receiver output and Ni is the input noise leveWhere B is the system band width, k B is the Boltzmann constant and T is the temperature in Kelvin. Taking into consideration that there is an additional processing gain due to the integration over several pulse.Another limiting case, referred to as the blocker case, is the scenario of a large target with maximum RCS being present very close to a radar at a minimal distance of operation. This sets the requirement on the front-end linearity in terms of input-referred 1dB compression point (IP1dB), which should be typically above 15 dBm. Combination of both mentioned limiting cases results in a requirement on the receivers dynamic range (DR), which usually should be above 70 dB HB Series of microwave motion sensor module are X-Band Mono-static DRO Doppler transceiver front-end module. These modules are designed for movement detection, like intruder alarms, occupancy modules and other innovative ideas. The module consists of Dielectric Resonator Oscillator (DRO), microwave mixer and patch antenna. His Application Note highlights some important points when designing-in HB100 module. Most of the points are also applicable to other models in this series. Header Pins can be used to connected the terminals (+5V, IF, GND) to the amplifier circuit as well as mounting support. Other mounting methods may be used. Wave-solder the module onto PCBA is possible but processes has to be evaluated to prevent deterioration. No-cleaning process is recommended. Caution must be taken to avoid applying pressure or stresses to the chassis of the module. As it may cause performance deterioration.Connect the power supply, Ground and amplifier circuitry at the designed terminals. Designation of the connection terminals are printed on the PCB.