FI116987B - Method and apparatus for calibrating horizontal and vertical channels in a double-polarized weather radar - Google Patents

Description

• 1

Method and equipment for calibrating horizontal * and vertical channels on two weather radars

The invention relates to a double pol; 5 channel horizontal (H) and vertical (V) calibration.

The invention also relates to apparatus for roaming dual polarized weather radar H and V4.

In prior art solutions, calibration is accomplished by feeding signals from the signal generator to the system by using tail couplings or directing the radar toward a fixed object. These pre-ankle systems do not allow easy real-time cocks to be needed during normal operation in a changing environment. In particular, changing temperatures can cause errors in the measuring system.

U.S. Patent 5,500,646 describes a Doppler radar with a signal to the receivers for calibration purposes. However, only a portion can then be calibrated.

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The object of the present invention is to overcome the * * m of the above-described technique. . "; provide a whole new type of method and equipment for H and V channel caliber polarized weather radar in real time.

The object of the invention is achieved by the use of a secondary input and I. This calibration signal is normally received on the channel of the radar receiver, and the observed differences between the channels are used for calibration information for weather echoes.

5 High power transmission from primary feed can also be used as a caliber secondary feed can be used as a receiving antenna.

More particularly, the method according to the invention is characterized in that in the characterizing part of claim 1.

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Further, the apparatus according to the invention is characterized by what is said in the characterizing part of the cap 16.

The invention offers significant advantages over conventional technology.

15

The invention improves the radar calibration accuracy and enables calibration ti during normal operation. Real-time calibration allows for even more accurate calibration, which improves the overall accuracy of the measuring system ... efficient detection of potential equipment failures.

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The invention will now be described in more detail with reference to the following examples.

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for the works shown in the accompanying figures, in which: * «4 f •. * ··, Figure 1 shows the basic configuration of a dual polarized weather radar according to prior art * * · * 25.

• · • · ♦ • * * ··· ·. * * *. Figure 2 is a block diagram of the first calibration process as a biscuit · ** 3

Figure 4 is a block diagram illustrating the invention of the third calibration scheme

As shown in Figure 1, the dual polarized weather radar comprises the following elements typically comprising an input element 2 and a power amplifier 3. A system 5 with a main oscillator 1 coupled to the input element 2. not used, amplifier 3 acts as an oscillator.

The output of the power amplifier 3 is coupled to at least one of the duplexers 7 by means of Pola, which divides the signal into horizontal (H) and vertical (V) components. Depending on the radar, the H and V components are transmitted alternately (alternately) or sa

Of the duplexers 7, the H and V components of the signal are supplied to the ortho-rhythm S11 by directing a reflector 8 into the atmosphere.

At reception, the H and V components are separated by the duplexers 7 of the ortho-mode input 9 into the H channel 4 and the V channel of the radar receiver, whereby ... the receivers 4 and 5 have an output of the detected signal for further processing.

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Fig. 2 is a block diagram of a calibration sequence using the secondary secondary supply 10 of the antenna dish 8 according to the invention.

a · «a a« ♦ / ··, The secondary input is linearly polarized in a plane that provides • Λ t * f 25 the primary input of the ortho form with 9 levels of polarization.

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The difference between the polarization levels causes the calibration signal to divide a a a 4

The low power calibration signal at the radar operating frequency, which is 1 to the main oscillator of the system, is fed from the input element 2 to the secondary transmitted towards the primary input 9.

5 The low power calibration signal can be pulsed and its pulse repetition selected to be the same as the pulse repetition frequency of the radar high power transmission, n also a continuous wave signal may be used if the high power transmission is during roaming.

10 When using a pulsed calibration signal, the transmission of the calibration signal and the mouth is synchronized so that the calibration signal is received at the port of the selected region instead of Ilir, where strong atmospheric echo is not best

The calibration signals are received by the H and V channels of the radar receiver during normal radar operation, and the differences between the channels are monitored.

The differences between the channels are used as calibration information in actual weather conditions. FIG. 3 is a block diagram of the calibration path radar transmission paths. 20 uses a secondary supply 10 disposed in the center of the antenna dish 8 in the embodiment of the polarizer 6 to transmit on the "I H and V channel", m φ · · s '··' The secondary supply 10 is linearly polarized in a plane forming • * 25 angles with the 9 polarization plan of the primary feed of the ortho-shape.

• * * · «• · ·, · * ·. The difference in polarization levels allows the secondary supply • · · 5

The signal from the secondary supply is directed to the duplexer 12 and its rotation receiver 11 which is locked to the radar main oscillator. H-1 reception is made alternately during normal radar operation, Channel 5 is used as calibration information for actual weather echoes.

The method described in Figure 2 can be used simultaneously with the pattern by connecting a low power signal from the input element 2 to the input via duplexer 12.

10

The correct placement of the secondary feed 10 is essential to the invention. Because it has a straightforward direct connection to the primary supply 9, it is therefore advantageous that the s supply is typically located at the center of the dish 8 and typically corresponds to the supply 9. For the system and method, it is still important that the 15 input and output signals are connected directly or indirectly to it.

Figure 4 is a block diagram of a calibration trace along radar transmission paths. a secondary supply 10 disposed at the center of the antenna dish 8.

• · · • · * '. In the 20 format, polarizer 6 is used to transmit the H-μ • * »radar either alternately or simultaneously.

The secondary input 10 is linearly polarized in a plane sam 9 * · «9. ···. ortho-form primary feed with 9 polarization planes.

• * 25. An RF switch 13 is disposed between the secondary supply 10 and the duplexer 12 ♦ ♦♦ 6 used as calibration information for actual weather echoes. The common RF switch to receiver eliminates measurement errors in the polarization channel

When coupling a low power signal from an input element 2 to a secondary 5 via a duplexer 12 and an RF switch, the solid state illustrated in Figure 4 also uses a radar to calibrate reception paths. In this case, the RF switch actuates the H and V polarization alternately from the secondary input 10. When the bound transmission, both the transmission and the receiving path are measured, the following alternate preferred embodiments of the invention are as follows: The secondary supply 10 may be linearly polarized a wavefront primary input 9 with a polarization plane 15 - The difference between the polarization planes is able to divide the calibration signal into a component H-j in the primary ortho input 9.

The secondary supply 10 may also be circularly polarized, where appropriate; , also contains H and V components.

e · · • · »*. 20 • * · • i · - The polarization of the secondary supply may be parallel to the ortho-mode * · · larisation if operated in alternation.

• m ^ t. · * ·. - The low power calibration signal at the radar operating frequency, which is * »25 to the ice oscillator main oscillator, is fed from the input element 2 to the secondary: and transmitted towards the primary input 9.

7 - The calibration transmission and high power transmission are synchronized so that the caliber is received at the selected region port where the atmosphere is present instead of the atmospheric echo.

5 - The calibration signals are received by the H and V channels of the radar receiver for normal operation of the radar, and the differences between the channels are monitored.

- Channel differences are used as calibration information for actual ones: 10 - Continuous wave calibration transmission can also be used if high power is disabled during calibration.

The apparatus has the following alternatives according to the invention: 15 - The secondary supply 10 is linearly polarized in a plane which forms an angle with the polarization plane of the primary ortho input 9.

The secondary supply 10 may also be circularly polarized, possibly accepting the primary supply of both polarized ones.

* ♦ · v · 20 919 · '·] - The polarization of the secondary supply may be in the same direction as the ortho (9 1 9 ** 1 | polarization if operated in alternation).

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III

'1 - A coaxial cable or waveguide is used to supply the calibration signal from • 9 9 9 25 to 2 secondary input 10.

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Claims (15)

A method for calibrating at least two polarized channels in two radar radars, which method - generates a radar signal in an amplifier unit (2,3) With a <RTIgt; oscillator (1), </RTI> 10. divides the radar signal into at least two components (H,> polarity). : (9) and the reflector (8), 15 - atmospheric signals are received by the primary: (9) by the reflector (8), characterized in that during or between normal operation • * · 20 * • * · * ·· *! - an input signal is applied to the secondary supply (10) Every second to the secondary supply (9) and this signal is received by the counter input (9) and used for calibration purposes "i; to compensate for the difference between the channels (H, V)." · A · ** · 25. A method according to claim 1, characterized in that the orbital shape of the radar • * * I \ ··· [ n primary feed (9) and move! * * Λ m. m. Method according to Claim 1 or 2, characterized in that the i-feed (10) is linearly polarized in a plane which forms a 45-degree primary feed (9) with the polarization plane. A device according to any one of the preceding claims or a combination thereof, characterized in that the difference between the polarization levels provides the H and V components of the calibration signal in the primary ortho-input (9). A device according to any one of the preceding claims or a combination thereof, characterized in that the secondary supply (10) is circularly polarized, which also has an H and V component. 6. A method as claimed in any one of the preceding claims, or combination thereof, characterized in that the low-frequency calibration 15 at the radar operating frequency is locked to the main oscillator of the radar system, fed to an input elemental input (10) and transmitted towards the primary input (9). A device according to any one of the preceding claims or a combination thereof, characterized in that the low frequency calibration signal is pulsed and 5 J · *. 20 hair is the same as the pulse repetition frequency of a high power radar transmission. • · Ϊ »·« • * * · · •]! 8. A method according to any one of the preceding claims or a combination thereof, characterized in that the calibration transmission and the high power transmission are a synchronous calibration signal is received instead of the atmospheric echo in the selected area poo. * 25 strong atmospheric echoes are not present. A or a combination of any of the preceding claims or a combination thereof 10. According to any one of the preceding claims, or a combination thereof, characterized in that continuous wave Kali can also be used if high power transmission is prevented during calibration. 11. A device as claimed in any one of the preceding claims, or a combination thereof, characterized in that the polarizer (6) is used for transmitting on the HV and HV channels. A device according to any one of the preceding claims or a combination thereof, characterized in that the difference between the polarization planes allows the input (10) to receive both the H and the V component from the radar transmission. 13. A device according to any one of the preceding claims or a combination thereof, characterized in that the signal from the secondary supply is then duplexed 15 to a calibration receiver (11) which is locked in 14. A converter according to any one of the preceding claims or a combination thereof, characterized in that the reception of H 'and V polarization is carried out alternately during paint application. • · · 20 • · · · ·, ·,; The adapter according to any one of the preceding claims or a combination thereof; characterized in that it is used simultaneously with this method, a low power signal from the input element (2) to the secondary input (10). ··% (12). ♦ ψ ·· · 25 • · * · 16. Apparatus for calibrating different channels in dual polarized weather radar · The apparatus comprises: * · · - means for applying a radar signal to at least two Komf V) having different polarity, 5. primary input (9) and reflector (8). ) for transmitting these signals to the atmosphere and receiving your atmosphere, characterized in that the apparatus comprises a 10th secondary supply (10) disposed on a primary s; indictment and means for supplying a calibration signal to a secondary rigid system calibration. 15 The secondary supply (10) according to one of the preceding claims or a combination thereof, characterized in that the secondary supply (10) is located on the antenna dish (8) ,,, 18. The secondary supply (10) 10) Polarization is in the same direction as the 1 in 1 L form contour input (9) polarized if used alternately IM • · A device according to any one of the preceding claims or a combination thereof, characterized in that the secondary supply (10) is linearly polarized t • ≤ 25 forms a polarization of the primary supply (9) of the ortho-form at an angle of 45 degrees. • ♦ 1 · «m · •« A device according to any one of the preceding claims or a combination thereof, characterized in that the coaxial cable or waveguide is used to control; from the kundar input (10) to the calibration receiver (11) a duplexer (· «« • »1 9« 9 «* • • 1 99« < «