초록 ▼

An antenna calibration system consists mainly of a signal source, an antenna, a first radio frequency mixer, a first local oscillator, an power detecting device, a personal computer, and a servo amplifier. The signal source emits a signal, and the antenna receives the signal. The signal and the firs

An antenna calibration system consists mainly of a signal source, an antenna, a first radio frequency mixer, a first local oscillator, an power detecting device, a personal computer, and a servo amplifier. The signal source emits a signal, and the antenna receives the signal. The signal and the first local oscillator, which emits a signal, are emitted into the first radio frequency mixer. Then the first radio frequency mixer emits a signal into the energy detecting device which calculates the signal power, and transmits the power into the personal computer. The personal computer calculates the powers, and then transmits an angle control signal into the servo amplifier. The servo amplifier amplifies the signal, and then drives the antenna pedestal to turn until the antenna is aimed at the signal source. This can calibrate exactly the antenna's azimuth and elevation offset angle.

대표청구항 ▼

The invention claimed is: 1. A dish antenna calibration system, suitable for pointing calibration of an antenna system, at least comprising: a signal source, used to emit a first signal; an antenna, located in a fixed position, and used to receive the first signal; a first radio frequency mixer, wh

The invention claimed is: 1. A dish antenna calibration system, suitable for pointing calibration of an antenna system, at least comprising: a signal source, used to emit a first signal; an antenna, located in a fixed position, and used to receive the first signal; a first radio frequency mixer, wherein the first radio frequency mixer is electrically connected to the antenna, so that the antenna can transmit the first signal to the first radio frequency mixer; a first local oscillator, wherein the first local oscillator is electrically connected to the first radio frequency mixer and used to generate a second signal; the second signal is subsequently transmitted to the first radio frequency mixer in which the second signal is mixed with the first signal and thus a third signal is formed after the frequency is reduced; an energy detecting device, wherein the energy device is electrically connected to the first radio frequency mixer, so that the first radio frequency mixer can transmit the third signal to the energy detecting device and the power of the third signal can be measured by the energy detecting device; a personal computer, wherein the personal computer is electrically connected to the energy detecting device, so that the power of the third signal that has measured can be transmitted to the personal computer, and the measured power value can be calculated and compared by the personal computer; and a servo amplifier, wherein the servo amplifier is electrically connected to the personal computer, and after the measured power value is calculated and compared by the personal computer, the personal computer outputs an angle control signal, the angle control signal is subsequently amplified by the servo amplifier so as to continuously drive the antenna scanning until the antenna is aimed at the first signal emitted by the signal source. 2. The antenna calibration system of claim 1, wherein the first signal comprises a RF signal. 3. The antenna calibration system of claim 1, wherein the energy detecting device comprises a second local oscillator, and the second local oscillator is suitable for outputting a signal to the second radio frequency mixer and at least comprises: a direct digital synthesizer, wherein the direct digital synthesizer is used to generate a digital signal; a digital to analog converter, wherein the digital to analog converter is electrically connected to the direct digital synthesizer and is used to covert the digital signal generated by the direct digital synthesizer to an analog signal; a lowpass filter, wherein the lowpass filter is electrically connected to the digital to analog converter and is used to filter the signal with higher frequency inside the input analog signal, so that the signal with lower frequency inside the analog signal can pass the lowpass filter; and an amplifier, wherein the amplifier is electrically connected to the lowpass filter and is used to amplify the signal with lower frequency to a fourth signal and further input the fount signal to the second radio frequency mixer. 4. The dish antenna calibration system of claim 1, wherein the energy detecting device is used to receive the third signal generated by the first radio frequency mixer, at least comprising: a second local oscillator, used to generate a fourth signal; a second radio frequency mixer, wherein the second radio frequency mixer is electrically connected to the second local oscillator, and a fourth signal input from the second local oscillator is mixed with the third signal that is input to the second radio frequency mixer, so as to generate a fifth signal after its frequency is reduced; a bandpass filter, wherein the bandpass filter is electrically connected to the second radio frequency mixer, so that the second radio frequency mixer can transmit the fifth signal to the bandpass filter in which a portion of the fifth signal can be filtered, and the portion of the fifth signal That is not filtered can pass the bandpass filter; a logarithm amplifier, wherein the logarithm amplifier is electrically connected to the bandpass filter, so that the bandpass filter can transmit the portion of the fifth signal that is not filtered to the logarithm amplifier, and the portion of the fifth signal that is not filtered is amplified by the logarithm amplifier; and a voltage which is proportional to the input power of the logarithm amplifier is output; an analog to digital converter, wherein the analog to digital converter is electrically connected to the logarithm amplifier, so that the logarithm amplifier can transmit the voltage which is proportional to the input power of the logarithm amplifier, and the analog to digital convert is used to convert the voltage into a digital signal; and a microcontroller, wherein the microcontroller is electrically connected to the analog to digital converter, so that the digital signal can be processed in the microcontroller so as to obtain all the power value. 5. The dish antenna calibration system of claim 1, wherein the fifth signal comprises an intermediate frequency signal. 6. A calibration method for a dish antenna system, suitable for obtaining an azimuth offset angle and an elevation offset angle of the antenna system, comprising the following steps: (a) a calibration point being selected first, after an inclination Θcal from a true north 0° is precisely measured via an geodetic survey, then a signal source being placed on the calibration point, and a signal generated by the signal source being received by the antenna; (b) the antenna being first aimed at the signal source and a fast scanning of ±10 degrees (each interval ≦0.5 degree) being performed so as to draw a diagram of the received power, and the antenna being subsequently aimed to an orientation with a maximum signal power; (c) the antenna being aimed to a second time at the signal source and a big azimuth scanning with an interval ≦0.2 degree being performed to obtain a maximum value of the signal power and an inclination Θp between the antenna and the signal source; (d) the antenna being aimed to a third time at the signal source, a position with a power of 3dB attenuation being measured and a small azimuth scanning with an interval less than 0.05 degree being performed to measure the position of another point having the same power as a symmetric beam, and an arithmetic mean of these two positions being the azimuth value Θaz; (e) obtaining an elevation angle value Θel by performing the same as the stops used to obtain the azimuth value Θ az; (f) obtaining the Θaz and the Θ el, and the Θaz, wherein the Θel pointed by the antenna are used as a center and a deviation angle (Δ Ø=0.5 degree) is used as a radius to scan the antenna (like a conical scan); moreover, the power received by the antenna is used as a radius for drawing a diagram of the power received by the antenna, wherein if die power diagram is a circle or a symmetric ellipse, it means a pointing position of the antenna is right at the center position of the signal source; (g) obtaining an azimuth offset angle Θoff by subtracting the Θaz from the Θcal wherein the offset angle Θoff the azimuth and the elevation also can be obtained by using the same method; and (h) locating the signal source on the other calibration position and obtaining a position T of the calibration point from the precise measurement of the geodetic survey, wherein the inclination between the position T and the true north 0° is ΘT, and repeating the steps (b)˜(f) so as to obtain an inclination Θilr between the signal source and the true north 0°, and Θilr is between ΘT+0.2° and ΘT-0.2°.