A method for amplitude and phase registration of a GEOSAR receiving channel

Abstract

The application provides a GEOSAR receiving channel amplitude-phase registration method, which determines the lengths of cables at various levels of a receiving channel according to a satellite configuration layout, establishes a corresponding relationship between amplitude-phase values of each single machine and cable of the receiving channel and temperature, acquires amplitudes and phases of each receiving channel at normal temperature, determines amplitude-phase weighting values required for forming a receiving beam, determines initial values of amplitude-phase adjustors, arranges temperature measuring points of the single machines and cables on the satellite, and adjusts the amplitudes and phases of the receiving channel in real time. The application considers factors such as inherent amplitude-phase errors of the single machines and cables, influences of temperature changes on the amplitudes and phases, amplitude-phase weighting values required for the receiving beam, and the like, and ensures that the amplitudes and phases of the receiving channel are accurately controllable.

Description

Technical Field

[0001] This invention relates to the field of microwave imaging satellite overall design technology, specifically to a GEO SAR receiver channel amplitude and phase registration method. Background Technology

[0002] GEO SAR receiving systems generally employ multi-channel synthesis. The synthesis efficiency of the receiving channels is greatly affected by the amplitude and phase (referred to as "amplitude and phase") of the received signal. If the amplitude and phase of the received signal are inconsistent with the design values, it will cause mismatch between the receiving channels of the feed network, resulting in deviation of the receiving beam pointing and a decrease in the antenna receiving pattern gain. Ultimately, this will cause a decrease in the system sensitivity and ambiguity of the SAR image.

[0003] Therefore, there is an urgent need for a GEO SAR receive channel amplitude and phase registration method that can avoid mismatch between the receive channels of the feed network, which leads to deviation in the receiving beam pointing, a decrease in the antenna receiving pattern gain, and ultimately a decrease in the system sensitivity and ambiguity of the SAR image. Summary of the Invention

[0004] In view of this, the present invention provides a method for amplitude and phase registration of GEO SAR receiving channel, which takes into account factors such as the inherent amplitude and phase errors of the unit and cable, the influence of temperature changes on amplitude and phase, and the amplitude and phase weighting value required for the receiving beam, so as to ensure that the amplitude and phase of the receiving channel are accurate and controllable.

[0005] To achieve the above-mentioned objectives, the technical solution of this invention is as follows:

[0006] A method for amplitude and phase registration of a GEO SAR receiving channel, characterized in that it includes:

[0007] Step 1: Determine the length of each level of the receiving channel cable based on the satellite configuration layout.

[0008] Step 2: Establish the correspondence between the amplitude and phase values ​​of each unit and cable in the receiving channel and the temperature.

[0009] Step 3: Obtain the amplitude and phase of each receiving channel at room temperature.

[0010] Step 4: Determine the amplitude and phase weights required to form the receiving beam.

[0011] Step 5: Determine the initial amplitude and phase values ​​of the amplitude and phase regulator.

[0012] Step 6: Deploy temperature measurement points for individual units and cables on the satellite.

[0013] Step 7: Real-time amplitude and phase adjustment of the receiving channel.

[0014] Furthermore, step four is specifically as follows: Based on the requirements of the observation task, determine the amplitude weighting value D required for the receiving beam. Rn and phase weighting α Rn , 1≤n≤N.

[0015] Furthermore, step five is specifically as follows: based on the measured amplitude and phase values ​​of each receiving channel at room temperature and the amplitude and phase weighting values ​​required for the receiving beam, calculate the initial amplitude value D of the amplitude and phase adjuster. Rn ×A R01 / A R0n The initial phase value is α Rn +θ R01 -θ R0n The corresponding values ​​are then written into the amplitude and phase regulator.

[0016] Furthermore, step six involves deploying temperature measurement points for individual units and cables on the satellite, and connecting these temperature measurement points to a temperature acquisition processor, which can acquire the temperature of each individual unit and cable in real time on orbit.

[0017] Furthermore, step seven is implemented as follows: After the receiving system starts working, the temperature acquisition processor outputs the real-time temperature values ​​of each unit and cable to the amplitude-phase regulator. The amplitude-phase regulator uses the pre-stored mapping relationship between amplitude and temperature to calculate the cumulative amplitude value of each unit and cable on each receiving channel at the current temperature.

[0018] A Rn =A R1n ×A R2n ×A R低噪放n ×A R3n

[0019] θ Rn =θ R1n +θ R2n +θ R低噪放n +θ R3n

[0020] Among them, A R1n A R2n A R低噪放n A R3n θ represents the amplitude values ​​of the first-level cable, the second-level cable, the low-noise amplifier, and the third-level cable, respectively. R1n θ R2n θ R低噪放n θ R3n These represent the phase values ​​of the first-level cable, the second-level cable, the low-noise amplifier, and the third-level cable, respectively.

[0021] The amplitude and phase adjuster ultimately gives the current amplitude value as D. Rn ×A R01 / A Rn The current phase value is αRn +θ R01 -θ Rn It adjusts the amplitude and phase of the signal in real time.

[0022] Beneficial effects:

[0023] 1. This invention proposes a method for amplitude and phase registration of a GEO SAR receiving channel. The method determines the length of each level of cable in the receiving channel according to the satellite configuration layout, establishes the correspondence between the amplitude and phase values ​​of each unit and cable in the receiving channel and the temperature, obtains the amplitude and phase of each receiving channel at normal temperature, determines the amplitude and phase weighting value required to form the receiving beam, determines the initial amplitude and phase value of the amplitude and phase adjuster, deploys temperature measurement points of the unit and cable on the satellite, and adjusts the amplitude and phase of the receiving channel in real time.

[0024] 2. This invention takes into account factors such as the inherent amplitude and phase errors of individual units and cables, the impact of temperature changes on amplitude and phase, and the amplitude and phase weighting values ​​required for the receiving beam, to ensure that the amplitude and phase of the receiving channel are accurate and controllable.

[0025] 3. This invention can avoid the problem of mismatch between the receiving channels of the feed network, which leads to deviation in the receiving beam pointing and a decrease in the antenna receiving pattern gain, ultimately causing a decrease in the system sensitivity and ambiguity of the SAR image. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the connection of the GEO SAR receiving channel. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] like Figure 1 As shown, the amplitude and phase registration process of the GEO SAR receive channel is as follows:

[0029] The antenna receives wireless signals reflected from the ground and feeds the signals into the feed network. The feed network receives the wireless signals from the antenna and feeds the signals into the low-noise amplifier via a wired connection. The low-noise amplifier amplifies the signals from the feed network for the first time. The temperature acquisition processor outputs the acquired temperature values ​​of each unit and cable to the amplitude and phase modulator. The amplitude and phase modulator adjusts the amplitude and phase according to the temperature values ​​from the temperature acquisition processor and the pre-stored amplitude and phase values, and then feeds the signals into the combiner. The combiner combines the input signals and feeds them to the receiver. The receiver amplifies the signals for the second time. Figure 1 The connection diagram of the GEO SAR receiving channel is shown below, and the functions of each component are explained as follows:

[0030] Antenna: Feeds the wireless signals reflected from the ground into the feed network.

[0031] Feed network: Receives wireless signals from the antenna and feeds the signals into the low-noise amplifier via a wired connection.

[0032] Low-noise amplifier: performs the first amplification of the signal from the feed network and feeds the signal into the amplitude and phase modulator.

[0033] Temperature acquisition processor: Used to acquire the current temperature value of each unit and cable, and output the temperature value to the amplitude and phase regulator.

[0034] Amplitude and phase adjuster: Used to store the initial amplitude and phase values ​​(including the measured amplitude and phase values ​​of each receiving channel at room temperature and the amplitude and phase weighting values ​​required for the receiving beam) and the amplitude and phase values ​​of each unit and cable of the receiving channel at different temperatures (the amplitude and phase values ​​of each unit and cable at different temperatures are provided by the manufacturer of the unit and cable after measurement), and to receive the current temperature value output by the temperature acquisition processor and calculate the final amplitude and phase value at the current temperature.

[0035] Combiner: Used to combine input signals and feed them to the receiver.

[0036] Receiver: Receives signals from the combiner and amplifies the received signals a second time.

[0037] This invention specifically includes the following steps:

[0038] 1) Step 1: Determine the lengths of each stage of the receiving channel cables based on the satellite configuration:

[0039] Based on the satellite configuration diagram, measure the length R of each segment of the receiving channel cable. 1n R 2n R 3n (1≤n≤N), start the cable production. For example, R 11 This is the cable length between the connector corresponding to the first output channel of the feed network and the connector corresponding to the input channel of the low-noise amplifier 1; the same applies to others.

[0040] 2) Step Two: Establish the correspondence between the amplitude and phase values ​​of each unit and cable in the receiving channel and the temperature:

[0041] The amplitude and phase values ​​of each unit and cable in the receiving channel are measured and provided by the manufacturers, and the corresponding relationship is stored in the temperature acquisition processor.

[0042] 3) Step 3: Obtain the amplitude and phase of each receiving channel at room temperature:

[0043] After all the receivers and cables for all receiving channels are assembled, measure the amplitude A of each receiving channel. R0n (1≤n≤N) and phase θ R0n (1≤n≤N).

[0044] 4) Step Four: Determine the amplitude and phase weights required to form the receiving beam:

[0045] Based on the requirements of the observation mission, determine the amplitude weighting value D required for the receiving beam. Rn (1≤n≤N) and phase weighting value α Rn (1≤n≤N). For example, the weighted method can use the sinc function.

[0046] 5) Step Five: Determine the initial amplitude and phase values ​​of the amplitude and phase adjuster:

[0047] Based on the measured amplitude and phase values ​​of each receiving channel at room temperature and the amplitude and phase weighting values ​​required for the receiving beam, the initial amplitude value of the amplitude and phase adjuster is calculated to be D. Rn ×A R01 / A R0n (1≤n≤N), the initial phase value is α Rn +θ R01 -θ R0n (1≤n≤N), write the corresponding values ​​into the amplitude and phase regulator.

[0048] 6) Step Six: Deploy temperature measurement points for individual units and cables on the satellite:

[0049] Temperature measurement points for individual units and cables are deployed on the satellite (for example, by attaching thermistors), and these temperature measurement points are connected to a temperature acquisition processor, allowing the temperature of each individual unit and cable to be acquired in real time on orbit.

[0050] 7) Step Seven: Real-time Amplitude and Phase Adjustment of the Receiving Channel:

[0051] After the receiving system starts working, the temperature acquisition processor outputs the real-time temperature values ​​of each unit and cable to the amplitude-phase modulator. The amplitude-phase modulator uses the pre-stored mapping relationship between amplitude and temperature to calculate the cumulative amplitude value of each unit and cable on each receiving channel at the current temperature.

[0052] A Rn =A R1n ×A R2n ×A R低噪放n ×A R3n (1≤n≤N)

[0053] θ Rn =θ R1n +θ R2n +θ R低噪放n +θ R3n (1≤n≤N)

[0054] Among them, A R1n A R2n A R低噪放n A R3nθ represents the amplitude values ​​of the first-level cable, the second-level cable, the low-noise amplifier, and the third-level cable, respectively. R1n θ R2n θ R低噪放n θ R3n These represent the phase values ​​of the first-level cable, the second-level cable, the low-noise amplifier, and the third-level cable, respectively.

[0055] The amplitude and phase adjuster ultimately gives the current amplitude value as D. Rn ×A R01 / A Rn (1≤n≤N), the current phase value is α Rn +θ R01 -θ Rn (1≤n≤N), the amplitude and phase of the signal are adjusted in real time.

[0056] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A GEO SAR receive channel amplitude-phase registration method, characterized in that, include: Step 1: Determine the length of each stage of the receiving channel cable based on the satellite configuration layout; Step 2: Establish the correspondence between the amplitude and phase values ​​of each unit and cable in the receiving channel and the temperature; Step 3: Obtain the amplitude and phase of each receiving channel at room temperature; Step 4: Determine the amplitude and phase weights required to form the receiving beam; Step 5: Determine the initial amplitude and phase values ​​of the amplitude and phase regulator; Step Six: Deploy temperature measurement points for individual units and cables on the satellite; Step 7: Real-time amplitude and phase adjustment of the receiving channel; The specific method for step four is as follows: Based on the requirements of the observation task, determine the amplitude weighting value D required for the receiving beam. Rn and phase weighting α Rn , 1≤n≤N; Step seven is as follows: After the receiving system starts working, the temperature acquisition processor outputs the real-time temperature values ​​of each unit and cable to the amplitude-phase regulator. The amplitude-phase regulator uses the pre-stored mapping relationship between amplitude and temperature to calculate the cumulative amplitude value of each unit and cable on each receiving channel at the current temperature. A Rn =A R1n ×A R2n ×A R低噪放n ×A R3n θ Rn =θ R1n +θ R2n +θ R低噪放n +θ R3n Among them, A R1n A R2n A R低噪放n A R3n θ represents the amplitude values ​​of the first-level cable, the second-level cable, the low-noise amplifier, and the third-level cable, respectively. R1n θ R2n θ R低噪放n θ R3n These represent the phase values ​​of the first-level cable, the second-level cable, the low-noise amplifier, and the third-level cable, respectively. The amplitude and phase adjuster ultimately gives the current amplitude value as D. Rn ×A R01 / A Rn The current phase value is α Rn +θ R01 -θ Rn It adjusts the amplitude and phase of the signal in real time.

2. The method of claim 1, wherein, Step five is as follows: Based on the measured amplitude and phase values ​​of each receiving channel at room temperature and the amplitude and phase weighting values ​​required for the receiving beam, calculate the initial amplitude value D of the amplitude and phase adjuster. Rn ×A R01 / A R0n The initial phase value is α Rn +θ R01 -θ R0n The corresponding values ​​are then written into the amplitude and phase regulator.

3. The method of claim 1, wherein, The specific method for step six is ​​as follows: deploy temperature measurement points for individual units and cables on the satellite, and connect these temperature measurement points to the temperature acquisition processor so that the temperature of each individual unit and cable can be acquired in real time on orbit.

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