Satellite-borne UCB transponder

Abstract

The application discloses a satellite-borne UCB transponder, which comprises a receiving unit, a ranging signal processing unit and a transmitting unit; when the transponder receives a signal, a satellite uplink measurement and control signal is input into the receiving unit, the receiving unit demodulates and outputs a ranging signal and sends the ranging signal to the ranging signal processing unit, the ranging signal processing unit performs phase temperature compensation and amplitude adjustment on the received ranging signal, and then sends the ranging signal to the transmitting unit to output a satellite downlink measurement and control signal after modulation and amplification. The UCB transponder of the application adopts two-stage low-noise amplifiers and two-stage preamplifier attenuators which are alternately combined at the front end of the receiving unit channel, so that the noise coefficient and the gain of the transponder are adjustable, and the receiving sensitivity can meet various requirements of users.

Description

Technical Field

[0001] This invention belongs to the field of aerospace telemetry and control, and relates to a satellite transponder. Background Technology

[0002] This task stemmed from the development of the UCB transponder for a series of high-orbit satellites. The telemetry, tracking, and command (TT&C) subsystem is a critical system for satellites, and the transponder is the core unit of the satellite TT&C system. The UCB transponder is a classic product that uses a unified C-band carrier side-tone TT&C system and is applied to multiple satellite models.

[0003] Currently, different satellite models place varying requirements on the receiving sensitivity and transmitting power of transponders, necessitating redesigns to meet diverse user needs. One of the primary functions of a transponder is ranging, with the zero-range value being a key indicator. Physically, this refers to the testing error caused by phase delay of the ranging signal within the transponder, which needs to be subtracted from the test value to calculate the actual satellite-to-ground distance. Currently, the zero-range value of transponders varies significantly with temperature, also requiring redesign. Summary of the Invention

[0004] The technical problem solved by the present invention is to overcome the shortcomings of the prior art and provide a spaceborne UCB transponder with a unified side tone ranging system and sensitivity that meets various user needs.

[0005] The technical solution of the present invention is: a spaceborne UCB transponder, comprising: a receiving unit, a ranging signal processing unit, and a transmitting unit; when the transponder receives a signal, the satellite uplink telemetry and control signal is input to the receiving unit, the receiving unit demodulates and outputs the ranging signal and sends it to the ranging signal processing unit, the ranging signal processing unit performs phase temperature compensation and amplitude adjustment on the received ranging signal, and then sends it to the transmitting unit for modulation and amplification before outputting the satellite downlink telemetry and control signal.

[0006] The receiving unit includes a first low-noise amplifier, a first pre-attenuator, a second low-noise amplifier, a second pre-attenuator, a first down-converter, an intermediate frequency amplifier, a second down-converter, a receiving local oscillator module, a VCO module, and a demodulation module. The satellite uplink telemetry and control signal is amplified by the first low-noise amplifier. This amplified signal is then attenuated by the first pre-attenuator and then amplified by the second low-noise amplifier. The amplified signal is further attenuated by the second pre-attenuator. The output attenuated signal is down-converted by the first down-converter to output an intermediate frequency signal. The intermediate frequency signal is sent to the intermediate frequency amplifier for amplification and filtering. The signal is sent to the second down-converter for further down-conversion. The down-converted signal then enters the demodulation module for demodulation. The demodulation module outputs the satellite remote control subcarrier signal, ranging signal, AGC control signal, and frequency error signal. The ranging signal output by the demodulation module is sent to the ranging signal processing unit. The demodulation module outputs the AGC control signal to the intermediate frequency amplifier for intermediate frequency amplification amplitude control. The demodulation module outputs the frequency error signal to the VCO module for frequency control of the crystal oscillator signal output by the VCO module. The VCO module outputs the crystal oscillator signal to the receiving local oscillator module, which generates two local oscillator signals and outputs them to the first and second down-converters respectively.

[0007] The ranging signal processing unit includes a ranging signal phase temperature compensation circuit and a ranging signal amplitude adjustment circuit. After receiving the ranging signal output from the receiving unit, the ranging signal phase temperature compensation circuit performs ranging signal phase temperature compensation, sends the temperature-compensated ranging signal to the ranging signal amplitude adjustment circuit for amplitude adjustment, and then sends the amplitude-adjusted ranging signal to the transmitting unit.

[0008] The ranging signal phase temperature compensation circuit includes a preset temperature control voltage conversion circuit and a ranging signal phase adjustment circuit. The ranging signal output from the receiving unit is input to the ranging signal phase adjustment circuit. The preset temperature control voltage conversion circuit generates a phase control voltage that changes with the ambient temperature and sends the phase control voltage to the ranging signal phase adjustment circuit. The ranging signal phase adjustment circuit performs ranging signal phase temperature compensation on the input ranging signal according to the input phase control voltage and sends the compensated ranging signal to the ranging signal amplitude adjustment circuit.

[0009] The preset temperature control voltage conversion circuit includes resistors R1, R2, R3, and R4. One end of resistor R1 serves as the power input terminal. The common end of resistors R2 and R3 serves as the bias voltage input terminal connected to the other end of resistor R1. The common other end of resistors R2 and R3 and one end of resistor R4 are connected together as the compensation control voltage output terminal connected to the ranging signal phase adjustment circuit. The other end of resistor R4 is grounded.

[0010] The ranging signal phase adjustment circuit includes an inductor L1, a capacitor C1, a capacitor C2, a resistor R5, and a diode V1. One end of the inductor L1 is connected to a preset temperature-controlled voltage conversion circuit as a compensation control voltage input terminal, and the other end of the inductor L1 is connected to the negative terminal of the diode V1 to provide a control voltage. One end of the capacitor C1 is connected to the receiving unit as a ranging signal input terminal, and the other end of the capacitor C1 is also connected to the negative terminal of the diode V1 to provide a ranging signal. One end of the resistor R5 is connected to the positive terminal of the diode V1 as a DC bias. One end of the capacitor C2 is also connected to the positive terminal of the diode V1 as a compensated ranging signal terminal, and the other end of the capacitor C2 is connected to the ranging signal amplitude adjustment circuit as a ranging signal output terminal.

[0011] The transmitting unit includes a transmitting crystal oscillator module, a transmitting local oscillator module, a modulation module, a low-pass filter, a band-pass filter, and a transmitting signal amplifier. The transmitting crystal oscillator module generates a crystal oscillator signal for the transmitting local oscillator module, which generates the carrier wave of the satellite downlink telemetry and control signal and outputs it to the modulation module. Simultaneously, the satellite telemetry subcarrier signal and the ranging signal input from the ranging signal processing unit are also sent to the modulation module. The modulation module modulates the satellite telemetry subcarrier signal and the ranging signal onto the carrier wave of the satellite downlink telemetry and control signal using frequency modulation to obtain the satellite downlink telemetry and control signal. The satellite downlink telemetry and control signal is input to the low-pass filter, and after low-pass filtering, it is output to the band-pass filter. After band-pass filtering, the satellite downlink telemetry and control signal is sent to the transmitting signal amplifier. The transmitting signal amplifier circuit amplifies the power of the filtered satellite downlink telemetry and control signal before outputting it.

[0012] The aforementioned signal amplification circuit employs an adjustable output power circuit.

[0013] The advantages of this invention compared to the prior art are:

[0014] 1) The front end of the UCB transponder receiver unit channel adopts an alternating combination of two-stage low-noise amplifiers and two-stage pre-attenuators, which makes the transponder noise figure and gain adjustable, and the receiving sensitivity meets various user needs.

[0015] 2) The UCB transponder incorporates a ranging signal phase temperature compensation circuit and a ranging signal adjustment circuit, enabling it to compensate for zero-value temperature errors. This circuit performs phase temperature compensation and amplitude adjustment on the ranging signal received and demodulated from the transponder, reducing fluctuations in the zero-value distance due to temperature changes.

[0016] 3) The UCB transponder transmitting unit is designed with an output signal amplification circuit and the power supply voltage is adjusted to make the output power continuously adjustable. By adjusting the power supply voltage, the output power is adjustable to ensure that the output measurement and control signal level meets the requirements. Attached Figure Description

[0017] Figure 1 Design scheme diagram for spaceborne UCB transponder

[0018] Figure 2 Schematic diagram of transponder ranging signal phase temperature compensation circuit

[0019] Figure 3 Working principle diagram of phase temperature compensation for ranging signal processing

[0020] Figure 4 Schematic diagram of the signal amplification circuit; Detailed Implementation

[0021] A satellite-borne UCB transponder includes: a receiving unit, a ranging signal processing unit, and a transmitting unit; when the transponder receives signals, the satellite uplink telemetry and control signal is input to the receiving unit, the receiving unit demodulates and outputs the ranging signal and sends it to the ranging signal processing unit, the ranging signal processing unit performs phase temperature compensation and amplitude adjustment on the received ranging signal, and then sends it to the transmitting unit for modulation and amplification before outputting the satellite downlink telemetry and control signal.

[0022] The receiving unit includes a first low-noise amplifier, a first pre-attenuator, a second low-noise amplifier, a second pre-attenuator, a first down-converter, an intermediate frequency amplifier, a second down-converter, a receiving local oscillator module, a VCO module, and a demodulation module. The satellite uplink telemetry and control signal is amplified by the first low-noise amplifier. This amplified signal is then attenuated by the first pre-attenuator and then amplified by the second low-noise amplifier. The amplified signal is further attenuated by the second pre-attenuator. The output attenuated signal is down-converted by the first down-converter to output an intermediate frequency signal. The intermediate frequency signal is sent to the intermediate frequency amplifier for amplification and filtering. The signal is sent to the second down-converter for further down-conversion. The down-converted signal then enters the demodulation module for demodulation. The demodulation module outputs the satellite remote control subcarrier signal, ranging signal, AGC control signal, and frequency error signal. The ranging signal output by the demodulation module is sent to the ranging signal processing unit. The demodulation module outputs the AGC control signal to the intermediate frequency amplifier for intermediate frequency amplification amplitude control. The demodulation module outputs the frequency error signal to the VCO module for frequency control of the crystal oscillator signal output by the VCO module. The VCO module outputs the crystal oscillator signal to the receiving local oscillator module, which generates two local oscillator signals and outputs them to the first and second down-converters respectively.

[0023] The ranging signal processing unit includes a ranging signal phase temperature compensation circuit and a ranging signal amplitude adjustment circuit. After receiving the ranging signal output from the receiving unit, the ranging signal phase temperature compensation circuit performs ranging signal phase temperature compensation, sends the temperature-compensated ranging signal to the ranging signal amplitude adjustment circuit for amplitude adjustment, and then sends the amplitude-adjusted ranging signal to the transmitting unit.

[0024] The ranging signal phase temperature compensation circuit includes a preset temperature control voltage conversion circuit and a ranging signal phase adjustment circuit. The ranging signal output from the receiving unit is input to the ranging signal phase adjustment circuit. The preset temperature control voltage conversion circuit generates a phase control voltage that changes with the ambient temperature and sends the phase control voltage to the ranging signal phase adjustment circuit. The ranging signal phase adjustment circuit performs ranging signal phase temperature compensation on the input ranging signal according to the input phase control voltage and sends the compensated ranging signal to the ranging signal amplitude adjustment circuit.

[0025] The preset temperature control voltage conversion circuit includes resistors R1, R2, R3, and R4. One end of resistor R1 serves as the power input terminal. The common end of resistors R2 and R3 serves as the bias voltage input terminal connected to the other end of resistor R1. The common other end of resistors R2 and R3 and one end of resistor R4 are connected together as the compensation control voltage output terminal connected to the ranging signal phase adjustment circuit. The other end of resistor R4 is grounded.

[0026] The ranging signal phase adjustment circuit includes an inductor L1, a capacitor C1, a capacitor C2, a resistor R5, and a diode V1. One end of the inductor L1 is connected to a preset temperature-controlled voltage conversion circuit as a compensation control voltage input terminal, and the other end of the inductor L1 is connected to the negative terminal of the diode V1 to provide a control voltage. One end of the capacitor C1 is connected to the receiving unit as a ranging signal input terminal, and the other end of the capacitor C1 is also connected to the negative terminal of the diode V1 to provide a ranging signal. One end of the resistor R5 is connected to the positive terminal of the diode V1 as a DC bias. One end of the capacitor C2 is also connected to the positive terminal of the diode V1 as a compensated ranging signal terminal, and the other end of the capacitor C2 is connected to the ranging signal amplitude adjustment circuit as a ranging signal output terminal.

[0027] The transmitting unit includes a transmitting crystal oscillator module, a transmitting local oscillator module, a modulation module, a low-pass filter, a band-pass filter, and a transmitting signal amplifier. The transmitting crystal oscillator module generates a crystal oscillator signal for the transmitting local oscillator module, which generates the carrier wave of the satellite downlink telemetry and control signal and outputs it to the modulation module. Simultaneously, the satellite telemetry subcarrier signal and the ranging signal input from the ranging signal processing unit are also sent to the modulation module. The modulation module modulates the satellite telemetry subcarrier signal and the ranging signal onto the carrier wave of the satellite downlink telemetry and control signal using frequency modulation to obtain the satellite downlink telemetry and control signal. The satellite downlink telemetry and control signal is input to the low-pass filter, and after low-pass filtering, it is output to the band-pass filter. After band-pass filtering, the satellite downlink telemetry and control signal is sent to the transmitting signal amplifier. The transmitting signal amplifier circuit amplifies the power of the filtered satellite downlink telemetry and control signal before outputting it.

[0028] The present invention will now be described in detail with reference to the accompanying drawings.

[0029] 1. Overall solution for transponder

[0030] The spaceborne modular UCB transponder employs a unified C-band side-tone ranging system. The satellite uplink telemetry and control signals use frequency modulation, while the satellite downlink telemetry and control signals use phase modulation. It is capable of receiving, demodulating, and modulating ranging signals, receiving and demodulating satellite remote control signals, and modulating and transmitting satellite downlink telemetry signals. The satellite remote control and telemetry signals are modulated remote control and telemetry signal subcarriers in PSK format.

[0031] The transponder consists of three parts: a receiving unit, a ranging signal processing unit, and a transmitting unit.

[0032] Overall composition diagram as follows Figure 1 As shown.

[0033] 2. Transponder Receiver Unit Design

[0034] The receiving unit adopts a two-conversion receiver scheme, consisting of two-stage low-noise amplifiers, two-stage pre-attenuators, downconverter 1, intermediate frequency amplifier, downconverter 2, receiving local oscillator module, VCO module and demodulation module.

[0035] The receiving unit input signals are: satellite uplink telemetry and control signals, with the operating frequency carrier being the international standard C uplink telemetry and control frequency band, 5.8GHz-6.6GHz, and the modulation signals being ranging signals and satellite remote control subcarrier signals, with the modulation method being frequency modulation.

[0036] The receiving unit works as follows: The satellite uplink telemetry and control signal is input to a two-stage low-noise amplifier module and a two-stage pre-attenuator, then enters downconverter 1, where the frequency is converted to approximately 100MHz-150MHz. This is then converted to an intermediate frequency amplifier for amplification and filtering. The output intermediate frequency signal is sent to downconverter 2 for further downconversion, reducing the frequency to approximately 25MHz. The signal after this second downconversion enters the demodulation module for demodulation. The demodulation module outputs the satellite remote control subcarrier signal, ranging signal, AGC control signal, and frequency error signal. Specifically, the demodulated satellite remote control subcarrier signal is sent to other satellite equipment for processing. The demodulated ranging signal is sent to the ranging signal processing unit. The demodulation module outputs the AGC control signal to intermediate frequency amplifier 1 for intermediate frequency amplification amplitude control. The demodulation module outputs the frequency error signal to the VCO module for frequency control of the crystal oscillator signal output by the VCO module. The VCO module outputs the crystal oscillator signal to the receiving local oscillator module, which generates two local oscillator signals and outputs them to downconverter 1 and downconverter 2 respectively.

[0037] Receiver channel sensitivity design: The receiver channel employs an alternating combination of two-stage low-noise amplifiers and two-stage pre-attenuators, allowing for adjustable noise figure and gain. The attenuator attenuation value ranges from 12dB to 2dB. The transponder noise figure determines the signal-to-noise spectral density ratio of the demodulated remote control subcarrier signal, thus determining the transponder's sensitivity. Adjustments can be made according to user requirements during use. Table 1 is a comparison table of empirical values ​​for pre-attenuation and transponder sensitivity.

[0038] Table 1 Comparison of Pre-attenuation and Transponder Sensitivity

[0039]

[0040] 3. Design of the transponder ranging signal processing unit

[0041] The ranging signal processing unit consists of a ranging signal phase temperature compensation circuit and a ranging signal amplitude adjustment circuit.

[0042] The ranging signal received and demodulated by the transponder is compensated for phase temperature and its amplitude is adjusted in this part of the circuit to reduce the fluctuation of the transponder's zero distance value with temperature changes.

[0043] The working principle of phase temperature compensation in ranging signal processing: The working principle of the phase temperature compensation circuit for ranging signals is as follows... Figure 3As shown, the system comprises two parts: a ranging signal phase adjustment circuit and a preset temperature-controlled voltage conversion circuit. The ranging signal is input to the ranging signal phase adjustment circuit, while the preset temperature-controlled voltage conversion circuit provides a control voltage that varies with ambient temperature based on the transponder's zero-value temperature error data. This control voltage controls the transmission phase offset of the ranging signal phase adjustment circuit. When the ranging signal passes through the ranging signal phase adjustment circuit, its phase has been corrected for temperature errors. The subsequent ranging signal amplitude adjustment circuit amplifies, limits, and filters the output ranging signal, ensuring that the phase and amplitude of the output ranging signal remain stable.

[0044] Design of a phase temperature compensation circuit for ranging signals:

[0045] The schematic diagram of the transponder ranging signal phase temperature compensation circuit is attached. Figure 2 As shown. The left side is the preset temperature control voltage conversion circuit, and the right side is the ranging signal phase adjustment circuit.

[0046] The preset temperature-controlled voltage conversion circuit includes a thermistor R3 and conventional resistors R1, R2, and R4. Based on the transponder's zero-value temperature error data, the preset temperature-controlled voltage conversion circuit provides a control voltage that varies with ambient temperature.

[0047] One end of resistor R1 serves as the power input terminal. The common end of resistors R2 and R3 serves as the bias voltage input terminal and is connected to the other end of resistor R1. The other common end of resistors R2 and R3 is connected together with one end of resistor R4 as the compensation control voltage output terminal and is connected to the ranging signal phase adjustment circuit. The other end of resistor R4 is grounded.

[0048] Based on the data analysis of the change of the zero value of the transponder ranging distance with temperature, the compensation control voltage / temperature relationship provided by the preset temperature control voltage conversion circuit is a quadratic curve, which can meet the compensation requirements.

[0049] To ensure verifiability and meet usage requirements, the temperature compensation network of the preset temperature control voltage conversion circuit adopts a typical four-resistor network.

[0050] In the diagram, the temperature coefficient of the thermistor R3 is negative. R3 is a medium-resistance thermistor, with a resistance between 100kΩ and 300kΩ. R4 is a low-resistance thermistor, with a resistance between 2kΩ and 9kΩ.

[0051] The ranging signal phase adjustment circuit includes a varactor diode V1, an inductor L1, a resistor R5, and DC blocking capacitors C1 and C2. Diode V1 is an electrically adjustable varactor diode, with its equivalent capacitance and bias voltage exhibiting a monotonically changing relationship. Diode V1 and resistor R5 form a phase-shifting network. L1 is a high-frequency choke coil, providing DC bias for the diode. When the ranging signal passes through the phase-shifting network, phase adjustment is performed to achieve the function of phase temperature error correction.

[0052] One end of inductor L1 is connected to the preset temperature control voltage conversion circuit as the compensation control voltage input terminal, and the other end of inductor L1 is connected to the negative terminal of diode V1 to provide control voltage. One end of capacitor C1 is the receiving unit as the ranging signal input terminal, and the other end of capacitor C1 is also connected to the negative terminal of diode V1 to provide the ranging signal. One end of resistor R5 is connected to the positive terminal of diode V1 as DC bias. One end of capacitor C2 is connected to the positive terminal of diode V1 as the compensated ranging signal terminal, and the other end of capacitor C2 is connected to the ranging signal amplitude adjustment circuit as the ranging signal output terminal.

[0053] Phase compensation mechanism: From the perspective of the transponder ranging path, at a certain temperature, the zero distance value is proportional to the phase delay of the ranging signal. When the zero distance value changes with temperature, it can be equivalent to a change in the phase delay of the ranging signal.

[0054] The parameters of the temperature compensation network in the temperature-controlled voltage conversion circuit are preset based on the transponder's zero-point temperature change curve, ensuring that the compensation control voltage / temperature relationship conforms to the quadratic compensation curve. As the ambient temperature changes, the compensation control voltage output by the voltage conversion circuit alters the DC bias of diode V1 in the ranging signal phase modulation circuit, changing the capacitance of the varactor diode V1 and consequently altering the phase of the ranging signal passing through the ranging phase adjustment circuit. At this point, the temperature compensation network causes the ranging signal phase delay to compensate for the change in the opposite direction, thus maintaining a stable zero-point distance for the transponder.

[0055] 4. Transponder Transmitter Unit Design

[0056] The transmitting unit adopts a locked-multiplier module loaded wave direct modulation scheme, which includes a transmitting crystal oscillator module, a transmitting local oscillator module, a modulation module, a low-pass filter, a band-pass filter, and a transmitting signal amplifier.

[0057] The output signal of the transmission channel is the satellite downlink telemetry and control signal. The operating frequency carrier is the international standard C downlink telemetry and control frequency band of 3.6GHz-4.3GHz. The modulation signal is the ranging signal and the satellite telemetry subcarrier signal. The modulation method is phase modulation.

[0058] Transmit channel operating principle: The transmit crystal oscillator module generates a crystal oscillator signal for the transmit local oscillator, which generates a C-band radio frequency signal, which is output to the modulation module as a downlink telemetry and control carrier. The ranging signal and the satellite telemetry subcarrier are input to the modulation module and modulated in the international standard C downlink telemetry and control frequency band using frequency-phase modulation. The modulated telemetry and control signal passes through low-pass and band-pass filters and is then input to the transmit signal amplifier circuit for power amplification.

[0059] See the description of the transmitted signal amplifier circuit. Figure 4 It adopts an adjustable output power circuit. By adjusting the power supply voltage, the output power can be adjusted to ensure that the output measurement and control signal level meets the requirements.

[0060] Table 2 Comparison of Power Supply Voltage and Transponder Output Power

[0061]

[0062]

[0063] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A spaceborne UCB transponder, characterized in that... include: The system consists of a receiving unit, a ranging signal processing unit, and a transmitting unit. When the transponder receives a signal, the satellite uplink telemetry and control signal is input to the receiving unit. The receiving unit demodulates and outputs the ranging signal, which is then sent to the ranging signal processing unit. The ranging signal processing unit performs phase temperature compensation and amplitude adjustment on the received ranging signal before sending it to the transmitting unit for modulation and amplification, and then outputs the satellite downlink telemetry and control signal. The receiving unit includes a first low-noise amplifier, a first pre-attenuator, a second low-noise amplifier, a second pre-attenuator, a first down-converter, an intermediate frequency amplifier, a second down-converter, a receiving local oscillator module, a VCO module, and a demodulation module. The satellite uplink telemetry and control signal is amplified by the first low-noise amplifier. This amplified signal is then attenuated by the first pre-attenuator and then amplified by the second low-noise amplifier. The amplified signal is further attenuated by the second pre-attenuator. The output attenuated signal is down-converted by the first down-converter to output an intermediate frequency signal. The intermediate frequency signal is sent to the intermediate frequency amplifier for amplification and filtering. The signal is sent to the second down-converter for further down-conversion. The down-converted signal then enters the demodulation module for demodulation. The demodulation module outputs the satellite remote control subcarrier signal, ranging signal, AGC control signal, and frequency error signal. The ranging signal output by the demodulation module is sent to the ranging signal processing unit. The demodulation module outputs the AGC control signal to the intermediate frequency amplifier for intermediate frequency amplification control. The demodulation module outputs the frequency error signal to the VCO module for frequency control of the crystal oscillator signal output by the VCO module. The VCO module outputs the crystal oscillator signal to the receiving local oscillator module, which generates two local oscillator signals and outputs them to the first and second down-converters respectively. The ranging signal processing unit includes a ranging signal phase temperature compensation circuit and a ranging signal amplitude adjustment circuit. After receiving the ranging signal output from the receiving unit, the ranging signal phase temperature compensation circuit performs ranging signal phase temperature compensation, sends the temperature-compensated ranging signal to the ranging signal amplitude adjustment circuit for amplitude adjustment, and then sends the amplitude-adjusted ranging signal to the transmitting unit. The ranging signal phase temperature compensation circuit includes a preset temperature control voltage conversion circuit and a ranging signal phase adjustment circuit. The preset temperature control voltage conversion circuit includes resistors R1, R2, R3, and R4. R3 is a medium-resistance thermistor, and R4 is a low-resistance thermistor. The ranging signal output from the receiving unit is input to the ranging signal phase adjustment circuit. The preset temperature control voltage conversion circuit generates a phase control voltage that changes with the ambient temperature and sends the phase control voltage to the ranging signal phase adjustment circuit. The ranging signal phase adjustment circuit performs ranging signal phase temperature compensation on the input ranging signal according to the input phase control voltage and sends the compensated ranging signal to the ranging signal amplitude adjustment circuit. The ranging signal phase adjustment circuit includes an inductor L1, a capacitor C1, a capacitor C2, a resistor R5, and a diode V1. One end of the inductor L1 is connected to a preset temperature-controlled voltage conversion circuit as a compensation control voltage input terminal, and the other end of the inductor L1 is connected to the negative terminal of the diode V1 to provide a control voltage. One end of the capacitor C1 is connected to the receiving unit as a ranging signal input terminal, and the other end of the capacitor C1 is also connected to the negative terminal of the diode V1 to provide a ranging signal. One end of the resistor R5 is connected to the positive terminal of the diode V1 as a DC bias. One end of the capacitor C2 is also connected to the positive terminal of the diode V1 as a compensated ranging signal terminal, and the other end of the capacitor C2 is connected to the ranging signal amplitude adjustment circuit as a ranging signal output terminal. The diode V1 is an electrically adjustable varactor diode.

2. The spaceborne UCB transponder according to claim 1, characterized in that: One end of resistor R1 serves as the power input terminal. The common end of resistors R2 and R3 is connected to the other end of resistor R1 as the bias voltage input terminal. The other common end of resistors R2 and R3 and one end of resistor R4 are connected together as the compensation control voltage output terminal, which is connected to the ranging signal phase adjustment circuit. The other end of resistor R4 is grounded.

3. The spaceborne UCB transponder according to claim 1, characterized in that: The transmitting unit includes a transmitting crystal oscillator module, a transmitting local oscillator module, a modulation module, a low-pass filter, a band-pass filter, and a transmitting signal amplification circuit. The transmitting crystal oscillator module generates a crystal oscillator signal for the transmitting local oscillator module, which generates the carrier wave of the satellite downlink telemetry and control signal and outputs it to the modulation module. Simultaneously, the satellite telemetry subcarrier signal and the ranging signal input from the ranging signal processing unit are also sent to the modulation module. The modulation module modulates the satellite telemetry subcarrier signal and the ranging signal onto the carrier wave of the satellite downlink telemetry and control signal using phase modulation to obtain the satellite downlink telemetry and control signal. The satellite downlink telemetry and control signal is input to the low-pass filter, filtered, and output to the band-pass filter. After band-pass filtering, the satellite downlink telemetry and control signal is sent to the transmitting signal amplification circuit. The transmitting signal amplification circuit amplifies the power of the filtered satellite downlink telemetry and control signal before outputting it.

4. A spaceborne UCB transponder according to claim 3, characterized in that: The aforementioned signal amplification circuit employs an adjustable output power circuit.

Images