| Collision rate is one of the most important aspect for the fuse penetration control.It’saccuracy has a strong effect on the final penetration. However, in actual situation,it’sdifficult to measure the the speed of penetration ammunition precisely. Most of the existing methods for measuring the the speed of penetration ammunition depend onthe contact way. Obviously, it will limit the measuring accuracy. In order to measurethe velocity real-time and precisely, this thesis presents a non-contact measuringmethod, which is based on the RF signal strength.Based on the the RF system of radar formula, the equation of collision velocitymeasurement is deduced. Since the equation is related to the target distance, it is necessary todetermine the relationship between the RF signal from the transmitter and the target distance.the rf transmission circuit is designed based on U2270B rf chip, which is used to measure andrecord the received rf signal amplitude under different distance. Different base functions arechosen to fit the test data using least squares method. Then the performances betweendifferent fitting results are compared and analyzed. And the best fitting curve is selected asfunction between the distance and the RF’s signal amplitude.Through the analysis of all kinds of radio frequency strength testing method, combinedwith the actual needs, logarithmic amplification method is chosen to detect the RF signal’samplitude. Taking AD8307log amplifier chip as the core, in this thesis, a controllable RFamplitude attenuation of intensity detection circuit is designed. The experiments show that,the designed circuit can be used in the pre-set situation. When the RF amplitude intensity isdetected, it is substituted into the function, which relates Intensity of rf signal amplitude anddistance, the target distance can be obtained. Then by using the collision velocitymeasurement formula, the velocity of penetration ammunition can be calculated. |
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