Phased array weather radar and amplitude and phase calibration system and method thereof

Abstract

The present invention discloses a phased array weather radar and an amplitude and phase calibration system and method thereof, and relates to the technical field of weather radars. The system includes a signal processing unit, a transmitting channel main link, a receiving channel main link, a radar antenna, a first calibration link, a second calibration link, a circulator and a coupler; the transmitting channel main link and the receiving channel main link are respectively connected to the signal processing unit, and the transmitting channel main link and the receiving channel main link are also respectively connected to the circulator; the first calibration link and the second calibration link are respectively connected to the signal processing unit, and the first calibration link and the second calibration link are also respectively connected to the coupler; the coupler is connected to the circulator and the radar antenna; the first calibration link or the second calibration link is arranged in a constant temperature chamber. The ambient temperature of the first calibration link or the second calibration link of the present invention is stable, which improves the amplitude and phase calibration accuracy of each transmitting channel and each receiving channel.

Description

Technical Field

[0001] The present invention belongs to the technical field of weather radars, and in particular relates to a phased array weather radar and an amplitude and phase calibration system and method thereof. Background Art

[0002] In order to avoid the amplitude difference and output power accuracy error of each transmitting channel and the amplitude difference and input power accuracy error of each receiving channel of the phased array weather radar, it is usually necessary to calibrate the amplitude of each transmitting channel and each receiving channel. The traditional calibration method usually adopts the method of adding a temperature compensation attenuator to the link. This method cannot guarantee the compensation of any curve in the full temperature range, resulting in low calibration accuracy.

[0003] For example, the Chinese patent document with application publication number CN109946662A discloses an in-machine calibration system for a phased array weather radar. For the transmitting channel or receiving channel, the amplitude difference and phase difference of each channel data are calculated, and the amplitude correction value and phase correction value are obtained after comparing with the design value, and the amplitude and phase correction of the transmitting channel or receiving channel are performed according to the correction parameters. The amplitude and phase accuracy of this method will change with the change of ambient temperature, resulting in low accuracy. Summary of the invention

[0004] The object of the present invention is to provide a phased array weather radar and an amplitude and phase calibration system and method thereof, so as to solve the problem that the traditional calibration method cannot ensure temperature compensation in the full temperature range, resulting in low calibration accuracy.

[0005] The present invention solves the above technical problems through the following technical solutions: an amplitude and phase calibration system for a phased array weather radar, comprising a signal processing unit, a transmitting channel main link, a receiving channel main link and a radar antenna, wherein the transmitting channel main link and the receiving channel main link are respectively connected to the signal processing unit;

[0006] The system further includes a first calibration link, a second calibration link, a circulator and a coupler; the transmitting channel main link and the receiving channel main link are also connected to the circulator respectively, the first calibration link and the second calibration link are respectively connected to the signal processing unit, the first calibration link and the second calibration link are also respectively connected to the coupler, and the coupler is connected to the circulator and the radar antenna; the first calibration link or the second calibration link is arranged in a constant temperature chamber;

[0007] The signal processing unit is used to generate a first baseband signal and a second baseband signal;

[0008] Used to obtain the actual power of the radio frequency signal generated by each transmission channel, collect the signal strength of the first reference signal, and adjust the signal strength of the corresponding transmission channel according to the signal strength of the first reference signal and the actual power of each radio frequency signal, so as to achieve amplitude and phase consistency and high-precision adjustment of each transmission channel;

[0009] and used to obtain the signal strength of the second reference signal, collect the actual power of each intermediate frequency signal, adjust the signal strength of the corresponding receiving channel according to the signal strength of the second reference signal and the actual power of each intermediate frequency signal, and achieve amplitude and phase consistency and high-precision adjustment of each receiving channel;

[0010] The transmission channel main link includes a plurality of transmission channels, each of the transmission channels is used to generate a radio frequency signal according to the first baseband signal;

[0011] The first calibration link is used to process the radio frequency signal after being transmitted by the circulator and the coupler to obtain a first reference signal;

[0012] The receiving channel main link includes a plurality of receiving channels, each of which is used to process the second reference signal after being transmitted by the coupler and the circulator to obtain an intermediate frequency signal;

[0013] The second calibration link is used to process the second baseband signal to obtain a second reference signal.

[0014] The first calibration link or the second calibration link of the present invention is placed in a constant temperature chamber, which ensures that the ambient temperature of the calibration link is stable, so that the gain of the calibration link is more accurate and the phase is more stable, which plays a role in stabilizing the amplitude and phase, avoids the problem of low calibration accuracy caused by the amplitude and phase accuracy of the calibration channel being affected by the ambient temperature, and improves the amplitude and phase calibration accuracy;

[0015] The present invention designs an independent first calibration link and a second calibration link. Each transmitting channel shares the first calibration link, and each receiving channel shares the second calibration link. The gain of the first calibration link or the second calibration link is fixed and does not change with temperature. The signal strength value of each transmitting channel and each receiving channel can be accurately obtained to achieve accurate amplitude and phase calibration. The first calibration link and the second calibration link are isolated from each other and have good isolation.

[0016] Furthermore, the system also includes a radio frequency switch and a radio frequency attenuator, the radio frequency switch is connected to the second calibration link and the radio frequency attenuator, and the radio frequency attenuator is connected to the first calibration link.

[0017] The first calibration link or the second calibration link is in a constant temperature chamber. The first calibration link forms a self-closed loop with the second calibration link through a radio frequency switch and a radio frequency attenuator. Before amplitude and phase calibration, the calibration link that is not in the constant temperature chamber is calibrated through the self-closed loop.

[0018] Furthermore, the constant temperature chamber includes a heating circuit and a closed cavity, the heating circuit includes an electric heater, a temperature sensor, a hysteresis comparator, a power supply and a switching switch, the electric heater and the temperature sensor are arranged in the closed cavity, the temperature sensor and the reference temperature are respectively connected to the two input ends of the hysteresis comparator, and the output end of the hysteresis comparator is connected to the power supply and the electric heater through the switching switch.

[0019] Furthermore, heat insulating materials are provided between the constant temperature chamber of the first calibration link and the second calibration link, the transmitting channel main link and the receiving channel main link;

[0020] Alternatively, thermal insulation materials are provided between the constant temperature chamber of the second calibration link and the first calibration link, the transmitting channel main link, and the receiving channel main link.

[0021] Indirect contact between the constant temperature cavity of the first calibration link or the second calibration link and other calibration links and the main link of the transceiver channel is achieved through the heat insulation material, which avoids excessive heat dissipation and reduces the continuous working time of the electric heater.

[0022] Furthermore, the first calibration link includes a frequency conversion circuit, a second filtering and amplifying circuit, a second amplitude and phase adjustment circuit, and a second equalizing circuit connected in sequence; the second calibration link includes a first equalizing circuit, a first amplitude and phase adjustment circuit, and a first filtering and amplifying circuit connected in sequence.

[0023] The flatness within the bandwidth is adjusted by the first equalization circuit and the second equalization circuit, thereby improving the broadband characteristics of the first calibration link and the second calibration link.

[0024] Furthermore, the first equalizing circuit adopts an equalizer, and the second equalizing circuit includes a microstrip transmission circuit and an RLC series circuit.

[0025] Based on the same concept, the present invention provides a phased array weather radar, comprising the amplitude and phase calibration system as described above.

[0026] Based on the same concept, the present invention provides an amplitude and phase calibration method for a phased array weather radar, wherein a transmitting channel main link and a receiving channel main link of the phased array weather radar are respectively connected to a circulator, a signal processing unit of the phased array weather radar is connected to a first calibration link and a second calibration link, the first calibration link and the second calibration link are respectively connected to a coupler, the coupler is connected to the circulator and a radar antenna; the first calibration link or the second calibration link is arranged in a constant temperature chamber; the calibration method includes transmitting channel calibration and receiving channel calibration; the transmitting channel calibration includes:

[0027] Obtain the actual power of the RF signal generated by each transmitting channel;

[0028] Collecting the signal strength of a first reference signal; wherein the first reference signal is obtained by processing the radio frequency signal transmitted by the circulator and the coupler by the first calibration link;

[0029] The signal strength of the corresponding transmission channel is adjusted according to the signal strength of the first reference signal and the actual power of each radio frequency signal, so as to achieve amplitude and phase consistency and high-precision adjustment of each transmission channel;

[0030] The receiving channel calibration comprises:

[0031] Acquire a signal strength of a second reference signal; wherein the second reference signal is obtained by processing a second baseband signal generated by a signal processing unit by a second calibration link;

[0032] Collecting the actual power of each intermediate frequency signal; wherein each intermediate frequency signal is obtained by each receiving channel processing the second reference signal after being transmitted by the coupler and the circulator;

[0033] The signal strength of the corresponding receiving channel is adjusted according to the signal strength of the second reference signal and the actual power of each intermediate frequency signal, so as to achieve amplitude and phase consistency and high-precision adjustment of each receiving channel.

[0034] Furthermore, the second calibration link is also connected to the first calibration link through a radio frequency switch and a radio frequency attenuator; before performing the transmission channel calibration and the receiving channel calibration, the calibration method further includes calibrating the calibration link that is not in the constant temperature chamber:

[0035] When the first calibration link is in the constant temperature chamber, the process of calibrating the second calibration link is as follows: closing the RF switch, the excitation signal generated by the signal processing unit is transmitted to the first calibration link through the RF switch and the RF attenuator after passing through the second calibration link, and finally flows back to the signal processing unit through the first calibration link; determining the output signal strength of the second calibration link according to the received signal strength of the signal processing unit and the gain of the first calibration link, and calibrating the receiving channel main link according to the output signal strength of the second calibration link;

[0036] When the second calibration link is in the constant temperature chamber, the process of calibrating the first calibration link is as follows: closing the RF switch, the excitation signal generated by the signal processing unit passes through the second calibration link, and then is transmitted to the first calibration link through the RF switch and the RF attenuator, and finally flows back to the signal processing unit through the first calibration link; determining the input signal strength of the first calibration link according to the received signal strength of the signal processing unit and the gain of the second calibration link, and calibrating the transmission channel main link according to the input signal strength of the first calibration link.

[0037] Further, the constant temperature chamber includes a heating circuit and a closed chamber, the heating circuit includes an electric heater, a temperature sensor, a hysteresis comparator, a power supply and a switching switch, the electric heater and the temperature sensor are arranged in the closed chamber, the temperature sensor and the reference temperature are respectively connected to the two input ends of the hysteresis comparator, and the output end of the hysteresis comparator is connected to the power supply and the electric heater through the switching switch;

[0038] The calibration method also includes temperature adjustment of the constant temperature chamber, specifically including:

[0039] When the difference between the temperature value collected by the temperature sensor and the reference temperature is greater than or equal to the upper limit of the set threshold range, the control switch is disconnected, the power supply is cut off, and the electric heater does not work;

[0040] When the difference between the temperature value collected by the temperature sensor and the reference temperature is less than the lower limit of the set threshold range, the control switch is closed, the power supply supplies power to the electric heater, and the electric heater works.

[0041] Beneficial Effects

[0042] Compared with the prior art, the advantages of the present invention are:

[0043] The present invention arranges the first calibration link or the second calibration link in a constant temperature chamber, thereby ensuring that the ambient temperature of the calibration link is stable, making the gain of the calibration link more accurate and the phase more stable, playing a role in stabilizing amplitude and phase, avoiding the problem of low calibration accuracy caused by the amplitude and phase accuracy of the calibration channel being affected by the ambient temperature, and improving the amplitude and phase calibration accuracy;

[0044] The present invention designs an independent first calibration link and a second calibration link. Each transmitting channel shares the first calibration link, and each receiving channel shares the second calibration link. The gain of the first calibration link or the second calibration link is fixed and does not change with temperature. The gain of the other calibration link can be accurately obtained through a self-closed loop, that is, the signal strength value of each transmitting channel and each receiving channel can be accurately obtained, thereby realizing accurate amplitude and phase calibration. The first calibration link and the second calibration link are isolated from each other, and the isolation is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 is a structural block diagram of an amplitude and phase calibration system of a phased array weather radar in an embodiment of the present invention;

[0047] Figure 2 This is a block diagram of the heating circuit in an embodiment of the present invention;

[0048] Figure 3 is a principle block diagram of a second calibration link in an embodiment of the present invention;

[0049] Figure 4 is a principle block diagram of a first calibration link in an embodiment of the present invention;

[0050] Figure 5 is a principle block diagram of a first equalization circuit in an embodiment of the present invention;

[0051] Figure 6 It is a principle block diagram of a second equalization circuit in an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The following is a clear and complete description of the technical solution in the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] The technical solution of the present application is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0054] Example 1

[0055] Figure 1 Figure 2 shows the structural block diagram of the amplitude and phase calibration system of the phased array weather radar. Figure 1As shown, the amplitude and phase calibration system includes a signal processing unit, a transmitting channel main link, a receiving channel main link, a radar antenna, a first calibration link, a second calibration link, a circulator and a coupler; the transmitting channel main link and the receiving channel main link are respectively connected to the signal processing unit, and the transmitting channel main link and the receiving channel main link are also respectively connected to the circulator; the first calibration link and the second calibration link are respectively connected to the signal processing unit, and the first calibration link and the second calibration link are also respectively connected to the coupler; the coupler is connected to the circulator and the radar antenna; the first calibration link or the second calibration link is arranged in a constant temperature chamber, so that the ambient temperature of the first calibration link or the second calibration link is stable, ensuring that the gain of the first calibration link or the second calibration link does not change with temperature, thereby ensuring that the reference signal does not change with temperature, and improving the amplitude and phase calibration accuracy of each transmitting channel and each receiving channel.

[0056] The signal processing unit generates a first baseband signal; the transmission channel main link includes multiple transmission channels, each transmission channel generates a radio frequency signal according to the first baseband signal generated by the signal processing unit, the radio frequency signal generated by each transmission channel is transmitted through a circulator and a coupler and then processed by a first calibration link to obtain a first reference signal, and each transmission channel shares the first calibration link; the actual power of the radio frequency signal generated by each transmission channel can be measured by a spectrum analyzer or a power meter, the signal processing unit collects the signal strength of the first reference signal, and adjusts the signal strength of the corresponding transmission channel according to the signal strength of the first reference signal and the actual power of each radio frequency signal, so as to achieve amplitude and phase consistency and high-precision adjustment of each transmission channel.

[0057] The signal processing unit generates a second baseband signal; the second calibration link processes the second baseband signal to obtain a second reference signal; the signal strength of the second reference signal can be measured using a spectrum analyzer or a power meter; the second reference signal is transmitted to the receiving channel main link via a coupler and a circulator; the receiving channel main link includes multiple receiving channels, each receiving channel processes the second baseband signal after being transmitted via the circulator and the coupler to obtain each intermediate frequency signal; the signal processing unit collects the actual power of each intermediate frequency signal, and adjusts the signal strength of the corresponding receiving channel according to the signal strength of the second reference signal and the actual power of each intermediate frequency signal, so as to achieve amplitude and phase consistency and high-precision adjustment of each receiving channel.

[0058] In a specific embodiment of the present invention, the amplitude and phase calibration system further includes a radio frequency switch and a radio frequency attenuator. The radio frequency switch is connected to the second calibration link and the radio frequency attenuator. The radio frequency attenuator is connected to the first calibration link.

[0059] A self-closed loop is formed by the signal processing unit, the second calibration link, the RF switch, the RF attenuator and the first calibration link. When the first calibration link or the second calibration link is in the constant temperature chamber, the calibration link that is not in the constant temperature chamber is calibrated through the self-closed loop before the amplitude and phase calibration.

[0060] Specifically, when the first calibration link is in the constant temperature chamber, the process of calibrating the second calibration link is as follows: the RF switch is closed, and the excitation signal generated by the signal processing unit is transmitted to the first calibration link through the RF switch and the RF attenuator after passing through the second calibration link, and finally flows back to the signal processing unit through the first calibration link; the output signal strength of the second calibration link is determined according to the received signal strength of the signal processing unit and the gain of the first calibration link, and the receiving channel main link is calibrated according to the output signal strength of the second calibration link;

[0061] When the second calibration link is in the constant temperature chamber, the process of calibrating the first calibration link is as follows: the RF switch is closed, and the excitation signal generated by the signal processing unit is transmitted to the first calibration link through the RF switch and the RF attenuator after passing through the second calibration link, and finally flows back to the signal processing unit through the first calibration link; the input signal strength of the first calibration link is determined according to the received signal strength of the signal processing unit and the gain of the second calibration link, and the transmission channel main link is calibrated according to the input signal strength of the first calibration link.

[0062] Since the signal in the first calibration link is weak and the heat generated is small, it is preferred that the first calibration link is placed in a constant temperature chamber, such as Figure 1 As shown. The first calibration link is in a constant temperature environment, and the accuracy of the second calibration link is calibrated through a self-closed loop, which improves the accuracy of the entire calibration link, thereby improving the accuracy of amplitude and phase calibration, and solving the problem of low amplitude and phase accuracy caused by ambient temperature during calibration. When the RF switch is disconnected, the first calibration link and the second calibration link work independently to complete the normal calibration function.

[0063] In a specific embodiment of the present invention, the constant temperature chamber includes a heating circuit and a closed chamber, such as Figure 2 As shown, the heating circuit includes an electric heater, a temperature sensor, a hysteresis comparator, a power supply and a switching switch. The electric heater and the temperature sensor are arranged in a closed cavity. The temperature sensor and the reference temperature are respectively connected to the two input ends of the hysteresis comparator, and the output end of the hysteresis comparator is connected to the power supply and the electric heater through the switching switch.

[0064] When the difference between the temperature value collected by the temperature sensor and the reference temperature is greater than or equal to the upper limit of the set threshold range, the control switch is disconnected, the power is cut off, and the electric heater does not work, so that the temperature of the closed cavity is constant within the set threshold range;

[0065] When the difference between the temperature value collected by the temperature sensor and the reference temperature is less than the lower limit of the set threshold range, the control switch is closed, the power supply supplies power to the electric heater, and the electric heater works to keep the temperature of the closed cavity constant within the set threshold range.

[0066] The calibration link mainly includes a mixer, a filter, an amplifier, etc. According to the chip data sheet, the gain of the device will decrease or the insertion loss will increase at high temperature, and the gain will increase or the insertion loss will decrease at low temperature. Conventional temperature compensation attenuators cannot perform accurate temperature compensation within the full temperature range. The present invention can keep the first calibration link or the second calibration link in a constant temperature working environment, thereby ensuring that the gain or insertion loss of the chip is relatively stable.

[0067] In this embodiment, the electric heater adopts a thin film heater, which is small in size and long in life; the hysteresis comparator adopts a positive hysteresis comparator; the power supply is based on a low voltage difference linear regulator design, with small ripple and more stable power supply, thereby ensuring the power supply stability of the electric heater.

[0068] In a specific embodiment of the present invention, heat insulation materials are provided between the constant temperature chamber of the first calibration link and the second calibration link, between the constant temperature chamber of the first calibration link and the main link of the transmitting channel, and between the constant temperature chamber of the first calibration link and the main link of the receiving channel;

[0069] Alternatively, thermal insulation materials are provided between the constant temperature chamber of the second calibration link and the first calibration link, between the constant temperature chamber of the second calibration link and the transmitting channel main link, and between the constant temperature chamber of the second calibration link and the receiving channel main link.

[0070] Indirect contact between the constant temperature cavity of the first calibration link or the second calibration link and the second calibration link or the first calibration link, the transmitting channel main link, and the receiving channel main link is achieved through insulation materials, thereby avoiding excessive heat dissipation and reducing the continuous working time of the electric heater.

[0071] In order to improve the performance consistency of radar products within a larger bandwidth, make the bandwidth wider and adapt to a wider range, it is necessary to perform broadband calibration on the radar products. In order to improve the broadband characteristics of the calibration link, the present invention designs an equalization circuit on the calibration link for adjusting the flatness within the bandwidth. In a specific embodiment of the present invention, Figure 3 As shown, the second calibration link includes a first equalization circuit, a first amplitude and phase adjustment circuit, and a first filtering and amplifying circuit connected in sequence; Figure 4 As shown, the first calibration link includes a frequency conversion circuit, a second filtering and amplifying circuit, a second amplitude and phase adjustment circuit, and a second equalization circuit connected in sequence.

[0072] The flatness within the bandwidth is adjusted by the first equalization circuit and the second equalization circuit, so that the amplitude within the working bandwidth remains unchanged as much as possible with the change of frequency, the frequency response characteristics of the calibration link are optimized, and the calibration is faster and easier.

[0073] For the signal of the second calibration link, the flatness adjustment within the bandwidth is achieved by selecting a suitable equalizer, such as Figure 5 Specifically, the flatness of the output signal of the second calibration link within the bandwidth is tested, and then different equalizers are selected so that the flatness of the output signal within the bandwidth meets the requirements, and the parameters of the equalizer can be determined.

[0074] For the signal of the first calibration link, an RLC series circuit is used to realize the calibration. The RLC discrete device is flexible and adjustable. The frequency of the resonance point is adjusted by LC, and the Q value of the circuit is adjusted by R. Specifically, Figure 6 As shown, the second equalization circuit includes a microstrip transmission circuit and an RLC series circuit. The flatness of the output signal of the first calibration link within the bandwidth is tested, and the RLC parameter value is adjusted in combination with the simulation software so that the flatness of the output signal within the bandwidth meets the requirements and the RLC parameters can be determined.

[0075] The gain of the first calibration link is stable and remains flat within the bandwidth, which can ensure both the amplitude and phase consistency of each transmitting channel and the accuracy of the actual power of each transmitting channel to avoid changes with temperature; the gain of the second calibration link is stable and remains flat within the bandwidth, which can ensure both the amplitude and phase consistency of each receiving channel and the accuracy of the actual power of each receiving channel to avoid changes with temperature.

[0076] Example 2

[0077] In order to realize the calibration of the phased array weather radar, a first calibration link is added to the main link of the transmitting channel of the phased array weather radar, and a second calibration link is added to the main link of the receiving channel of the phased array weather radar, such as Figure 1 As shown, the main link of the transmitting channel and the main link of the receiving channel are connected to the circulator respectively, the signal processing unit is connected to the first calibration link and the second calibration link, the first calibration link and the second calibration link are connected to the coupler respectively, the coupler is connected to the circulator and the radar antenna; the first calibration link or the second calibration link is arranged in a constant temperature chamber. The amplitude and phase calibration method of the present invention includes the calibration of the transmitting channel and the calibration of the receiving channel, wherein the calibration of the transmitting channel includes:

[0078] Step A1: The signal processing unit obtains the actual power of the radio frequency signal generated by each transmission channel; wherein the actual power of each radio frequency signal can be measured by a spectrum analyzer or a power meter, and then input into the signal processing unit through a first calibration link;

[0079] Step A2: The signal processing unit collects the signal strength of the first reference signal; wherein the first reference signal is obtained by the first calibration link processing the radio frequency signal after being transmitted by the circulator and the coupler;

[0080] Step A3: The signal processing unit adjusts the signal strength of the corresponding transmission channel according to the signal strength of the first reference signal and the actual power of each radio frequency signal, so as to achieve amplitude and phase consistency and high-precision adjustment of each transmission channel.

[0081] The receiving channel calibration includes:

[0082] Step B1: The signal processing unit obtains the signal strength of the second reference signal; wherein the second reference signal is obtained by processing the second baseband signal generated by the signal processing unit by the second calibration link, and the signal strength of the second reference signal can be measured by a spectrum analyzer or a power meter, and then input into the signal processing unit through the receiving channel main link;

[0083] Step B2: The signal processing unit collects the actual power of each intermediate frequency signal; wherein each intermediate frequency signal is obtained by each receiving channel processing the second reference signal transmitted by the coupler and the circulator;

[0084] Step B3: The signal processing unit adjusts the signal strength of the corresponding receiving channel according to the signal strength of the second reference signal and the actual power of each intermediate frequency signal, so as to achieve amplitude and phase consistency and high-precision adjustment of each receiving channel.

[0085] In a specific embodiment of the present invention, Figure 1 As shown, the second calibration link is also connected to the first calibration link through the RF switch and the RF attenuator; before performing the transmission channel calibration and the receiving channel calibration, the calibration method further includes calibrating the calibration link that is not in the constant temperature chamber:

[0086] When the first calibration link is in the constant temperature chamber, the process of calibrating the second calibration link is as follows: the RF switch is closed, and the excitation signal generated by the signal processing unit is transmitted to the first calibration link through the RF switch and the RF attenuator after passing through the second calibration link, and finally flows back to the signal processing unit through the first calibration link; the output signal strength of the second calibration link is determined according to the received signal strength of the signal processing unit and the gain of the first calibration link, and the receiving channel main link is calibrated according to the output signal strength of the second calibration link;

[0087] When the second calibration link is in the constant temperature chamber, the process of calibrating the first calibration link is as follows: the RF switch is closed, and the excitation signal generated by the signal processing unit is transmitted to the first calibration link through the RF switch and the RF attenuator after passing through the second calibration link, and finally flows back to the signal processing unit through the first calibration link; the input signal strength of the first calibration link is determined according to the received signal strength of the signal processing unit and the gain of the second calibration link, and the transmission channel main link is calibrated according to the input signal strength of the first calibration link.

[0088] In a specific embodiment of the present invention, the constant temperature chamber includes a heating circuit and a closed chamber, such as Figure 2 As shown, the heating circuit includes an electric heater, a temperature sensor, a hysteresis comparator, a power supply and a switch. The electric heater and the temperature sensor are arranged in a closed cavity. The temperature sensor and the reference temperature are respectively connected to the two input ends of the hysteresis comparator, and the output end of the hysteresis comparator is connected to the power supply and the electric heater through the switch. The calibration method also includes temperature adjustment of the constant temperature cavity, specifically including:

[0089] When the difference between the temperature value collected by the temperature sensor and the reference temperature is greater than or equal to the upper limit of the set threshold range, the control switch is disconnected, the power is cut off, and the electric heater does not work, so that the temperature of the closed cavity is constant within the set threshold range;

[0090] When the difference between the temperature value collected by the temperature sensor and the reference temperature is less than the lower limit of the set threshold range, the control switch is closed, the power supply supplies power to the electric heater, and the electric heater works to keep the temperature of the closed cavity constant within the set threshold range.

[0091] What is disclosed above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or modifications within the technical scope disclosed in the present invention, which should be covered within the protection scope of the present invention.

Claims

1. An amplitude and phase calibration system for a phased array weather radar, comprising a signal processing unit, a transmitting channel main link, a receiving channel main link and a radar antenna, wherein the transmitting channel main link and the receiving channel main link are respectively connected to the signal processing unit; characterized in that: The system further includes a first calibration link, a second calibration link, a circulator and a coupler; the transmitting channel main link and the receiving channel main link are also connected to the circulator respectively, the first calibration link and the second calibration link are respectively connected to the signal processing unit, the first calibration link and the second calibration link are also respectively connected to the coupler, and the coupler is connected to the circulator and the radar antenna; The first calibration link or the second calibration link is arranged in a constant temperature chamber; The signal processing unit is used to generate a first baseband signal and a second baseband signal; Used to obtain the actual power of the radio frequency signal generated by each transmission channel, collect the signal strength of the first reference signal, and adjust the signal strength of the corresponding transmission channel according to the signal strength of the first reference signal and the actual power of each radio frequency signal, so as to achieve amplitude and phase consistency and high-precision adjustment of each transmission channel; and used to obtain the signal strength of the second reference signal, collect the actual power of each intermediate frequency signal, adjust the signal strength of the corresponding receiving channel according to the signal strength of the second reference signal and the actual power of each intermediate frequency signal, and achieve amplitude and phase consistency and high-precision adjustment of each receiving channel; The transmission channel main link includes a plurality of transmission channels, each of the transmission channels is used to generate a radio frequency signal according to the first baseband signal; The first calibration link is used to process the radio frequency signal after being transmitted by the circulator and the coupler to obtain a first reference signal; The receiving channel main link includes a plurality of receiving channels, each of which is used to process the second reference signal after being transmitted by the coupler and the circulator to obtain an intermediate frequency signal; The second calibration link is used to process the second baseband signal to obtain a second reference signal.

2. The amplitude and phase calibration system of the phased array weather radar according to claim 1, characterized in that: The system further includes a radio frequency switch and a radio frequency attenuator. The radio frequency switch is connected to the second calibration link and the radio frequency attenuator. The radio frequency attenuator is connected to the first calibration link.

3. The amplitude and phase calibration system of the phased array weather radar according to claim 1, characterized in that: The constant temperature cavity includes a heating circuit and a closed cavity, the heating circuit includes an electric heater, a temperature sensor, a hysteresis comparator, a power supply and a switching switch, the electric heater and the temperature sensor are arranged in the closed cavity, the temperature sensor and the reference temperature are respectively connected to the two input ends of the hysteresis comparator, and the output end of the hysteresis comparator is connected to the power supply and the electric heater through the switching switch.

4. The amplitude and phase calibration system of the phased array weather radar according to claim 1, characterized in that: Heat insulation materials are provided between the constant temperature chamber of the first calibration link and the second calibration link, the transmitting channel main link, and the receiving channel main link; Alternatively, thermal insulation materials are provided between the constant temperature chamber of the second calibration link and the first calibration link, the transmitting channel main link, and the receiving channel main link.

5. The amplitude and phase calibration system of the phased array weather radar according to any one of claims 1 to 4, characterized in that: The first calibration link includes a frequency conversion circuit, a second filtering and amplifying circuit, a second amplitude and phase adjustment circuit and a second equalizing circuit connected in sequence; the second calibration link includes a first equalizing circuit, a first amplitude and phase adjustment circuit and a first filtering and amplifying circuit connected in sequence.

6. The amplitude and phase calibration system of the phased array weather radar according to claim 5, characterized in that: The first equalizing circuit adopts an equalizer, and the second equalizing circuit includes a microstrip transmission circuit and an RLC series circuit.

7. A phased array weather radar, characterized in that: The weather radar comprises an amplitude and phase calibration system as claimed in any one of claims 1 to 6.

8. A method for amplitude and phase calibration of a phased array weather radar, characterized in that: The main link of the transmitting channel and the main link of the receiving channel of the phased array weather radar are respectively connected to the circulator, the signal processing unit of the phased array weather radar is connected to the first calibration link and the second calibration link, the first calibration link and the second calibration link are respectively connected to the coupler, and the coupler is connected to the circulator and the radar antenna; The first calibration link or the second calibration link is arranged in a constant temperature chamber; the calibration method comprises a transmission channel calibration and a receiving channel calibration; The transmission channel calibration includes: Obtain the actual power of the RF signal generated by each transmitting channel; Collecting the signal strength of a first reference signal; wherein the first reference signal is obtained by processing the radio frequency signal transmitted by the circulator and the coupler by the first calibration link; The signal strength of the corresponding transmission channel is adjusted according to the signal strength of the first reference signal and the actual power of each radio frequency signal, so as to achieve amplitude and phase consistency and high-precision adjustment of each transmission channel; The receiving channel calibration comprises: Acquire a signal strength of a second reference signal; wherein the second reference signal is obtained by processing a second baseband signal generated by a signal processing unit by a second calibration link; Collecting the actual power of each intermediate frequency signal; wherein each intermediate frequency signal is obtained by each receiving channel processing the second reference signal after being transmitted by the coupler and the circulator; The signal strength of the corresponding receiving channel is adjusted according to the signal strength of the second reference signal and the actual power of each intermediate frequency signal, so as to achieve amplitude and phase consistency and high-precision adjustment of each receiving channel.

9. The amplitude and phase calibration method of phased array weather radar according to claim 8, characterized in that: The second calibration link is also connected to the first calibration link through a radio frequency switch and a radio frequency attenuator; before performing the transmission channel calibration and the receiving channel calibration, the calibration method further includes calibrating the calibration link that is not in the constant temperature chamber: When the first calibration link is in the constant temperature chamber, the process of calibrating the second calibration link is as follows: the RF switch is closed, and the excitation signal generated by the signal processing unit is transmitted to the first calibration link through the RF switch and the RF attenuator after passing through the second calibration link, and finally flows back to the signal processing unit through the first calibration link; Determine the output signal strength of the second calibration link according to the received signal strength of the signal processing unit and the gain of the first calibration link, and calibrate the receiving channel main link according to the output signal strength of the second calibration link; When the second calibration link is in the constant temperature chamber, the process of calibrating the first calibration link is as follows: the RF switch is closed, and the excitation signal generated by the signal processing unit is transmitted to the first calibration link through the RF switch and the RF attenuator after passing through the second calibration link, and finally flows back to the signal processing unit through the first calibration link; The input signal strength of the first calibration link is determined according to the received signal strength of the signal processing unit and the gain of the second calibration link, and the transmission channel main link is calibrated according to the input signal strength of the first calibration link.

10. The amplitude and phase calibration method of phased array weather radar according to claim 8 or 9, characterized in that: The constant temperature chamber comprises a heating circuit and a closed chamber, wherein the heating circuit comprises an electric heater, a temperature sensor, a hysteresis comparator, a power supply and a switching switch, wherein the electric heater and the temperature sensor are arranged in the closed chamber, wherein the temperature sensor and the reference temperature are respectively connected to two input ends of the hysteresis comparator, and the output end of the hysteresis comparator is connected to the power supply and the electric heater through the switching switch; The calibration method also includes temperature adjustment of the constant temperature chamber, specifically including: When the difference between the temperature value collected by the temperature sensor and the reference temperature is greater than or equal to the upper limit of the set threshold range, the control switch is disconnected, the power supply is cut off, and the electric heater does not work; When the difference between the temperature value collected by the temperature sensor and the reference temperature is less than the lower limit of the set threshold range, the control switch is closed, the power supply supplies power to the electric heater, and the electric heater works.

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