A transceiver time-sharing measurement communication integrated remote microwave rendezvous radar system

Abstract

A time-division multiplexing measurement and communication integrated long-range microwave rendezvous radar system employs a one-dimensional mechanically scanned and one-dimensional phase-scanned antenna at the A end of the aircraft and a wide-angle interferometer antenna at the B end. Precise angle measurement is achieved through single-pulse angle tracking at one end and wide-angle precision interferometric angle measurement at the other, constructing a dual-end heterogeneous system that enables both aircraft to perform ranging, velocity measurement, angle measurement, and communication capabilities. By using a narrow-beam, high-gain one-dimensional mechanically scanned and one-dimensional phase-scanned antenna at one end and a wide-angle interferometer antenna at the other, complementary forward and reverse links are formed, ensuring the large viewing angle requirement for long-range links. Simultaneously, the introduction of a phased array antenna improves the scanning and acquisition speed. The overall solution comprehensively considers the constraints of long range, large field of view, rapid acquisition, and multiple application modes.

Description

Technical Field

[0001] This invention relates to a time-division multiplexing measurement and communication integrated long-range microwave rendezvous radar system, belonging to the field of inter-satellite link technology. Background Technology

[0002] In projects such as near-Earth orbit space stations, the Moon, and Mars, it is necessary to achieve long-distance rendezvous and docking between two or more spacecraft. The microwave rendezvous radar system, as a typical secondary radar, is an important medium- and long-range measurement sensor of the GNC subsystem during the rendezvous and docking process. It can provide precise measurement data such as relative distance, speed, and angle between different spacecraft, and at the same time enable air-to-air communication between different spacecraft.

[0003] In existing technologies, microwave rendezvous radar systems can only provide complete range, velocity, angle and air-to-air communication information on one end of the aircraft. They mostly use wide-angle low-gain interferometer antennas for interferometric angle measurement, with typical operating distances in the hundreds of kilometers range. A few can reach the 750km range by using point-beam reflector antennas. However, they have not yet utilized phased array technology and cannot meet the requirements of wide-angle long-range coverage and rapid acquisition, tracking and measurement.

[0004] Existing phased array radar systems can meet the requirements of wide-angle coverage and rapid acquisition and tracking measurement. However, in existing primary phased array radar systems, the primary radar signals are transmitted and received in a time-division multiplexing manner, which cannot meet the requirements of two-way long-range measurement and communication for rendezvous and docking radars. In existing secondary phased array radar systems, a typical example is a secondary air traffic control radar, which adopts an interrogation-response system. After the interrogation pulse is sent, it waits to receive the response pulse train. The two-end equipment uses pulse trains with a certain time interval to interact. The effective data transmission time in each interaction is far less than 50% of the total time, resulting in very low bandwidth utilization. The pulse sequence is also not conducive to the use of high-precision ranging and velocity measurement methods such as spread spectrum measurement and carrier plethysmography.

[0005] Existing microwave rendezvous radar systems all use frequency division duplex (FDM) mode, with different frequencies for forward and reverse directions. When it is necessary to achieve arbitrary pairing measurements between two or more aircraft, additional hardware resources are required to accommodate frequency pairing. Existing communication systems use time division duplex mode, typically 4G and 5G mobile communication systems. These systems use communication signal formats based on wireless communication frames and do not have dedicated measurement signals, thus lacking the ability to integrate long-distance, high-precision measurement with communication.

[0006] In summary, existing systems cannot simultaneously meet the requirements of future rendezvous and docking application scenarios in terms of operating range, field of view, acquisition speed, and application modes. Summary of the Invention

[0007] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and solve the problem of integrated measurement and communication for rendezvous and docking.

[0008] The objective of this invention is achieved through the following technical solutions:

[0009] A time-division multiplexing measurement and communication integrated long-range microwave rendezvous radar system includes: a microwave radar and a microwave transponder; the microwave radar and the microwave transponder are each installed on an aircraft.

[0010] A microwave radar includes a radar antenna and a radar main unit. The radar antenna includes a one-dimensional electronically scanned phased array antenna and a one-dimensional servo mechanism. The phased array antenna adopts a design where the receiving and transmitting arrays share the same surface, and transmits and receives radio frequency signals at the same frequency in a time-division multiplexing manner. The radar main unit includes a radar transceiver channel and a radar processor. The radar transceiver channel converts the received radio frequency signal into a received intermediate frequency signal and converts the transmitted intermediate frequency signal into a transmitted radio frequency signal. The radar processor generates servo and beam control signals for the servo mechanism and the phased array antenna, and simultaneously transmits, receives, and processes the radar intermediate frequency signal to obtain ranging, velocity, angle measurement, and communication information.

[0011] A microwave transponder includes a transponder antenna and a transponder main unit. The transponder antenna is a wide-angle interferometer antenna, consisting of a set of array elements and a multiplexer switch. The array elements are time-division multiplexed by the multiplexer switch and transmit and receive radio frequency signals at the same frequency. The transponder main unit includes a transponder transceiver channel and a transponder processor. The transponder transceiver channel converts the received radio frequency signal into a received intermediate frequency signal and the transmitted intermediate frequency signal into a transmitted radio frequency signal. The transponder processor generates a selection signal for the antenna multiplexer switch, and simultaneously transmits, receives, and processes the transponder intermediate frequency signal to generate ranging, velocity, angle measurement, and communication information.

[0012] A measurement and communication method based on the aforementioned long-range microwave rendezvous radar system includes:

[0013] Microwave radar uses a single-pulse angle tracking method to obtain angle measurement values;

[0014] Microwave transponders obtain angle values ​​through interferometric angle measurement;

[0015] The two aircraft acquire ranging values ​​through a time-division coherent relay ranging method.

[0016] The two aircraft obtained velocity values ​​through a time-division coherent relay Doppler velocity measurement method.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] (1) This invention proposes a novel long-range microwave rendezvous radar system integrating measurement and communication. At the A end of the aircraft, a one-dimensional mechanically scanned antenna plus a one-dimensional phase-scanned antenna is used, and at the B end of the aircraft, a wide-angle interferometer antenna is used. Precise angle measurement is achieved by single-pulse angle tracking at one end and wide-angle precision interferometric angle measurement at the other end, thus constructing a dual-end heterogeneous system, enabling the two-end aircraft to have the capabilities of ranging, velocity measurement, angle measurement and communication. By using a narrow-beam high-gain one-dimensional mechanically scanned antenna plus a one-dimensional phase-scanned antenna at one end of the aircraft and a wide-angle interferometer antenna at the other end, complementary forward and reverse links are formed, thereby ensuring the requirement of a large field of view for long-distance links. At the same time, the introduction of phased array antennas improves the scanning acquisition speed. The overall scheme takes into account the comprehensive constraints of long distance, large field of view, fast acquisition and multiple application modes.

[0019] (2) This invention proposes a coherent ranging method with time division between transmission and reception, which overcomes the difficulty of time division between transmission and reception at the same frequency of the system. By maintaining open-loop spreading code tracking in the transmission time slot and forwarding the regenerated spreading code, spreading ranging is realized. Thus, the advantages of spreading ranging can be used to realize precise ranging between devices in the case of time division between transmission and reception.

[0020] (3) This invention proposes a time-division velocities measurement method to overcome the difficulty of time-division velocities at the same frequency of the system. By maintaining open-loop carrier tracking in the transmission time slot and forwarding the regenerated carrier, carrier Doppler velocities measurement is realized. Thus, in the case of time-division velocities measurement, the advantages of carrier Doppler velocities measurement can be used to realize precise velocities measurement between devices.

[0021] (4) This invention proposes a time-division measurement and communication signal format to overcome the difficulty of time-division of transmission and reception at the same frequency point in the system. Based on coherent forwarding ranging frames, it overcomes the interference of time-division switching of transmission and reception, and has a data transmission efficiency of nearly 50%.

[0022] (5) By adopting a time-division multiplexing system with the same frequency, the forward and reverse link frequencies are the same, which facilitates arbitrary pairing between two or more aircraft. It also makes it easier to standardize the hardware equipment of each aircraft's radar and transponder and make the software definable. This breaks through the limitations of the original microwave rendezvous radar frequency division duplex system, so that when two or more aircraft dock and measure each other, there is no need to consider the frequency pairing problem between the aircraft or the hardware compatibility problem, thus expanding the flexibility of rendezvous and docking missions. Attached Figure Description

[0023] Figure 1 A schematic diagram of the basic components of a measurement and communication integrated long-range microwave rendezvous radar system.

[0024] Figure 2 This is a schematic diagram of a coherent ranging method with time-division multiplexing.

[0025] Figure 3This is a schematic diagram of a coherent forwarding Doppler velocimetry method with time-division multiplexing.

[0026] Figure 4 It is a signal format for integrated time-division measurement and communication.

[0027] Figure 5 This is a schematic diagram of a radar system consisting of "A equipped with radar antenna - C equipped with radar antenna".

[0028] Figure 6 This is a schematic diagram of a radar system consisting of "B equipped with a transponder antenna - C equipped with a transponder antenna". Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0030] A time-division multiplexing measurement and communication integrated long-range microwave rendezvous radar system and measurement and communication method, such as Figure 1 As shown, the system consists of a microwave radar and a microwave transponder. The microwave radar is installed on aircraft A, and the microwave transponder is installed on aircraft B. The microwave radar includes a radar antenna and a radar main unit. The radar antenna includes a one-dimensional electronically scanned phased array antenna and a one-dimensional servo mechanism. The phased array antenna adopts a shared array design for receiving and transmitting, and transmits and receives radio frequency signals at the same frequency in a time-division multiplexing manner. The radar main unit includes a radar transceiver channel and a radar processor. The radar transceiver channel converts the received radio frequency signal into a received intermediate frequency signal and converts the transmitted intermediate frequency signal into a transmitted radio frequency signal. The radar processor generates servo control and beam control signals for the servo mechanism and the phased array antenna, and simultaneously transmits, receives, and processes the radar intermediate frequency signal to obtain ranging, velocity, angle measurement, and communication information. A microwave transponder includes a transponder antenna and a transponder main unit. The transponder antenna is an interferometer antenna, consisting of a set of array elements and a multiplexer switch. Multiple array elements of the antenna are time-division multiplexed through the multiplexer switch and transmit and receive radio frequency signals at the same frequency. The transponder main unit includes a transponder transceiver channel and a transponder processor. The transponder transceiver channel converts the received radio frequency signal into a received intermediate frequency signal and the transmitted intermediate frequency signal into a transmitted radio frequency signal. The transponder processor generates selection signals for the antenna multiplexer switch and simultaneously transmits, receives, and processes the transponder intermediate frequency signal to generate ranging, velocity, angle measurement, and communication information. The integrated measurement and communication long-range microwave rendezvous radar system acquires angle values ​​at the A-end aircraft using a single-pulse angle tracking method and at the B-end aircraft using an interferometer. It acquires ranging values ​​at both ends using a time-division coherent relay ranging method and a time-division coherent relay Doppler velocity measurement method. Communication is achieved at both ends by constructing an integrated measurement and communication signal format, enabling the system to perform ranging, velocity, angle measurement, and communication at both aircraft ends.

[0031] This invention, based on the constructed system, employs a coherent ranging method with time-division multiplexing. For example... Figure 2 As shown, the inter-vehicle ranging signal between aircraft A and aircraft B includes a transmission time slot and a reception time slot. The basic unit of each time slot is one spreading code period. One spreading code period is greater than twice the maximum inter-vehicle signal transmission delay T. Each aircraft's transmission time slot consists of N spreading code periods, and each aircraft's reception time slot consists of N+1 spreading code periods. The extra spreading code period in the reception time slot is used to wait for the inter-vehicle transmission delay. Therefore, the effective transmission efficiency is N / (2N+1). The larger N is, the closer it is to the maximum transmission efficiency of 50%. When aircraft A acts as the active ranging terminal, it transmits a forward inter-range ranging frame consisting of N spreading code cycles. After an inter-vehicle signal transmission delay T, aircraft B receives the forward inter-range ranging frame from aircraft A. Aircraft B performs spreading code tracking and demodulation. After receiving the forward inter-range ranging frame consisting of N spreading code cycles, it enters the transmission time slot, maintains open-loop spreading code tracking, and forwards the tracked and regenerated spreading code. It then transmits a reverse inter-range ranging frame consisting of N spreading code cycles. After an inter-vehicle transmission delay T, aircraft A receives the reverse inter-range ranging frame transmitted by aircraft B. According to the inter-vehicle transmission process, the time difference τ between the end of the forward inter-range ranging frame from aircraft A and the beginning of the reverse inter-range ranging frame from aircraft B is twice the inter-vehicle transmission delay T. Measuring τ at aircraft A allows the calculation of the inter-vehicle transmission delay T, thus obtaining the distance R between the two aircraft. The basic calculation formula is shown below:

[0032]

[0033] In the formula, c represents the speed of light, T represents the inter-device transmission delay, and τ represents the time difference between the end of the transmitted frame and the beginning of the received frame. The ranging value R obtained by spacecraft A is used as inter-device communication data. After data modulation, it is transmitted to spacecraft B along with the inter-device ranging frame. Spacecraft B performs spreading, tracking, and demodulation on the spreading code, thereby solving for the inter-device distance.

[0034] This invention, based on the constructed system, employs a time-division multiplexing coherent forwarding Doppler velocity measurement method. For example... Figure 3 As shown, a carrier signal is modulated based on coherent relay ranging. When spacecraft A acts as the active velocity measuring terminal, spacecraft A transmits a carrier modulated signal with the same duration as the ranging frame between the forward probes, at a frequency of f0, after an inter-probe transmission delay T and an additional velocity Doppler frequency shift f. d Subsequently, spacecraft B received a forward ranging frame from spacecraft A at a frequency of f0+f dThe B-type aircraft tracks and demodulates the carrier modulation signal. After receiving a signal with the same duration as the ranging frame between the forward probes, it enters the transmission time slot. During the transmission time slot, it maintains open-loop carrier tracking and forwards the regenerated carrier at a transmission frequency of f0+f. d The transmission duration is the same as the inter-reverse ranging frame, after which an inter-reverse transmission delay T is added and a velocity Doppler frequency shift f is applied again. d Subsequently, spacecraft A received the inter-reverse ranging frame transmitted by spacecraft B at a frequency of f0+2f. d According to the inter-vehicle transmission process, the frequency difference Δf between the frequency of the forward inter-vehicle ranging frame transmitted by spacecraft A and the frequency of the received reverse inter-vehicle ranging frame is integrated at spacecraft A over a time interval of ΔT. Every ΔT, a Doppler integral phase value φ(t) is obtained. The difference between these values ​​is then calculated to determine the velocity v between the two spacecraft. The basic calculation formula is shown below:

[0035]

[0036] In the formula, c represents the speed of light, ΔT represents the integration time, Δf represents the frequency difference between the transmitted and received frames, and φ(t) represents the Doppler integral phase value at time t. The velocity value v obtained by spacecraft A is used as inter-spacecraft communication data. After data modulation, it is transmitted to spacecraft B along with the inter-spacecraft ranging frame. Spacecraft B performs spread spectrum tracking demodulation on the spreading code, thereby solving for the inter-spacecraft velocity.

[0037] This invention, based on the constructed system, employs a time-division multiplexing measurement and communication integrated signal format. For example... Figure 4 As shown, the inter-device transmission signal adopts orthogonal dual-path BPSK modulation. The I path is a low-speed data frame, using spread spectrum plus BPSK modulation, mainly used for spread spectrum ranging and velocities, and also for transmitting low-speed measurement data. The Q path is a high-speed data frame, using BPSK modulation, used for transmitting high-speed communication data between the devices. Due to the transmission and reception switching in the system, the received signal is unstable at the moment of switching, which can easily cause interference to the starting data of the high-speed data frame, but the interference to the starting data of the low-speed data frame is negligible. Therefore, no independent additional synchronization word is set at the beginning of the high-speed data frame. During this period, the received data of the Q path is invalid until the additional synchronization word of the I path ends, and the demodulation of the Q path data begins. The carrier phases of the I and Q paths are orthogonal to each other, the frame headers are aligned, and the data rates are integer multiples of each other.

[0038] Based on the constructed system, this invention enables the establishment of rendezvous and docking measurement links between two or more aircraft. When an additional C aircraft is required during a flight mission, rendezvous and docking measurement and communication links can be established between any two aircraft due to their consistent frequency. Specifically, depending on the antenna configuration of the C aircraft, four configurations can be formed: "A with radar antenna - C with transponder antenna", "A with radar antenna - C with radar antenna", "B with transponder antenna - C with transponder antenna", and "B with transponder antenna - C with radar antenna". Among these, the configurations "A with radar antenna - C with transponder antenna" and "B with transponder antenna - C with radar antenna" are similar to... Figure 1 The basic configuration is the same; the "A with radar antenna - C with radar antenna" configuration is as follows: Figure 5 As shown, in this scenario, both aircraft are equipped with phased array antennas. Depending on mission requirements, one end can be designated as a transponder. Before the link is established, servo control and beam control signals are sent via the radar processor. A broadened beam is formed on the phased array antenna at the transponder end for the other end's radar to scan, acquire, and track. Once the tracking link is established, time-division multiplexing measurements and communication can be performed. The configuration of "B with transponder antenna - C with transponder antenna" is as follows: Figure 6 As shown, in this scenario, both aircraft are equipped with wide-beam multi-element antennas. Depending on mission requirements, one end can be designated as the radar end. Since both ends are wide-beam antennas, the antenna scanning and acquisition process can be skipped, allowing direct time-division multiplexing measurements and communication. Furthermore, when the antenna configuration changes according to mission requirements, since the frequency points are the same, the radar and transponder hardware can be modified without altering the backend processing via software definition. This eliminates the need to consider frequency pairing issues or hardware compatibility problems when two or more aircraft are docked for measurements, thus expanding the flexibility of rendezvous and docking missions.

[0039] Example:

[0040] A transceiver time-division measurement and communication integrated long-range microwave rendezvous radar system, such as... Figure 1 As shown, the wide-angle microwave rendezvous radar system consists of two parts: a wide-angle microwave radar and a wide-angle microwave transponder. The microwave radar is installed on aircraft A, and the microwave transponder is installed on aircraft B.

[0041] The microwave radar equipment on the aircraft consists of two main parts: a radar antenna and a radar main unit. The microwave radar antenna is composed of a one-dimensional electrically scanned phased array antenna and a one-dimensional servo mechanism. The phased array antenna uses a 32×32 element Ka-band waveguide slot array. The radar main unit consists of a radar transceiver channel with the same transmitting and receiving frequencies and an intermediate frequency radar processor. The radar transceiver channel converts the received Ka-band radio frequency signal into a 100MHz received intermediate frequency signal and converts the 100MHz transmitted intermediate frequency signal into a Ka-band transmitted radio frequency signal. The radar processor generates servo and wave control signals for the servo mechanism and the phased array antenna, and simultaneously processes and calculates the radar intermediate frequency signal to generate ranging, velocity, angle measurement, and communication data.

[0042] The microwave transponder equipment on the B aircraft consists of two main parts: a transponder antenna and a transponder main unit. The transponder antenna is composed of a set of array elements and a multiplexer switch, with multiple Ka-band horn elements forming a typical L-type interferometer array. The transponder main unit consists of a transponder transceiver channel with the same transmitting and receiving frequencies and a transponder processor. The transponder transceiver channel converts the received Ka-band radio frequency signal into a 100MHz received intermediate frequency signal and converts the 100MHz transmitted intermediate frequency signal into a Ka-band transmitted radio frequency signal. The transponder processor generates a selection signal for the antenna multiplexer switch, which generates a single-channel radio frequency transceiver signal. At the same time, it processes and calculates the radar intermediate frequency signal to generate ranging, velocity, angle measurement, and communication data.

[0043] The microwave radar antenna on aircraft A is equipped with a single-pulse angle tracking antenna and corresponding radar processing equipment, achieving precise angle measurement through phased array single-pulse angle tracking; the microwave transponder antenna on aircraft B is equipped with an interferometer antenna and corresponding transponder processing equipment, achieving precise angle measurement through interferometric angle measurement; through a dual-end heterogeneous design, both ends of the radar system have core active angle measurement capabilities, and on this basis, they also have active ranging, velocity measurement and communication capabilities.

[0044] The microwave radar equipment on aircraft A is characterized by a phased array antenna with one-dimensional mechanical scanning and one-dimensional electronic scanning. The antenna uses mechanical scanning in the elevation direction with a ±75° elevation field of view to achieve a wide range of elevation angle coverage, and uses fast electronic scanning in the azimuth direction with a ±45° azimuth field of view. Aircraft B's antenna uses a wide-beam small horn antenna array to achieve a field of view coverage of ±60°×±60° in both elevation and azimuth directions.

[0045] The A-end antenna features a narrow beam and high gain. In this embodiment, a 32×32 element Ka-band waveguide slot array is used, with a typical gain of 35dB and a 3dB beamwidth of approximately 3°. The B-end antenna features a wide beam and low gain, with a typical gain of 0dB and a 0dB gain beamwidth of ±60°×±60°. The A and B-end antennas complement each other to form a forward and reverse link. At this time, the equivalent power of the dual-end Ka-band transmitted radio frequency signal only needs to reach the order of 1W to ensure the long-distance measurement and communication requirements on the order of 1000km.

[0046] Spacecraft A and Spacecraft B use a time-division coherent relay ranging method for ranging. The inter-space ranging signal includes a transmit time slot and a receive time slot. The basic unit of each time slot is one spreading code period. Considering the maximum transmission delay on the order of 1000km and leaving a certain margin, one spreading code period can be taken as 10ms. The transmit time slot of each spacecraft consists of 10 spreading code periods, and the receive time slot of each spacecraft consists of 11 spreading code periods. The extra spreading code period in the receive time slot is used to wait for the inter-space transmission delay. The effective transmission efficiency is N / (2N+1)≈48%, which is close to the maximum transmission efficiency of 50%. When aircraft A acts as the active ranging unit, it transmits a forward ranging frame consisting of 10 spreading code cycles. After an inter-unit signal transmission delay T, aircraft B receives the forward ranging frame from aircraft A. Aircraft B performs spreading code tracking demodulation on the spreading code. After receiving the forward ranging frame consisting of 10 spreading code cycles, it enters the transmission time slot, maintains open-loop spreading code tracking in the transmission time slot, and forwards the tracked and regenerated spreading code. It transmits a total of 10 reverse ranging frames consisting of 10 spreading code cycles. After an inter-unit transmission delay T, aircraft A receives the reverse ranging frame transmitted by aircraft B. According to the inter-vehicle transmission process, the time difference τ between the end of the forward inter-vehicle ranging frame from aircraft A and the beginning of the reverse inter-vehicle ranging frame from aircraft B is twice the inter-vehicle transmission delay T. By measuring τ at aircraft A, the inter-vehicle transmission delay T can be calculated, thus obtaining the distance R between the two aircraft. The basic calculation formula is as follows:

[0047]

[0048] In the formula, c represents the speed of light, T represents the inter-device transmission delay, and τ represents the time difference between the end of the transmitted frame and the beginning of the received frame. The ranging value R obtained by spacecraft A is used as inter-device communication data. After data modulation, it is transmitted to spacecraft B along with the inter-device ranging frame. Spacecraft B performs spreading, tracking, and demodulation on the spreading code, thereby solving for the inter-device distance.

[0049] Spacecraft A and Spacecraft B are measured using a time-division multiplexing coherent Doppler velocimetry method. For example... Figure 2As shown, a carrier signal is modulated based on coherent relay ranging. When spacecraft A acts as the active velocity measuring terminal, spacecraft A transmits a carrier modulated signal with the same duration as the ranging frame between the forward probes, at a frequency of f0, after an inter-probe transmission delay T and an additional velocity Doppler frequency shift f. d Subsequently, spacecraft B received a forward ranging frame from spacecraft A at a frequency of f0+f d The B-type aircraft tracks and demodulates the carrier modulation signal. After receiving a signal with the same duration as the ranging frame between the forward probes, it enters the transmission time slot. During the transmission time slot, it maintains open-loop carrier tracking and forwards the regenerated carrier at a transmission frequency of f0+f. d The transmission duration is the same as the inter-reverse ranging frame, after which an inter-reverse transmission delay T is added and a velocity Doppler frequency shift f is applied again. d Subsequently, spacecraft A received the inter-reverse ranging frame transmitted by spacecraft B at a frequency of f0+2f. d According to the inter-vehicle transmission process, the frequency difference Δf between the frequency of the forward inter-vehicle ranging frame transmitted by spacecraft A and the frequency of the received reverse inter-vehicle ranging frame is integrated at spacecraft A over a time interval of ΔT. Every ΔT, a Doppler integral phase value φ(t) is obtained. The difference between these values ​​is then calculated to determine the velocity v between the two spacecraft. The basic calculation formula is shown below:

[0050]

[0051] In the formula, c represents the speed of light, ΔT represents the integration time, Δf represents the frequency difference between the transmitted and received frames, and φ(t) represents the Doppler integral phase value at time t. The velocity value v obtained by spacecraft A is used as inter-spacecraft communication data. After data modulation, it is transmitted to spacecraft B along with the inter-spacecraft ranging frame. Spacecraft B performs spread spectrum tracking demodulation on the spreading code, thereby solving for the inter-spacecraft velocity.

[0052] This invention, based on the constructed system, employs a time-division multiplexing measurement and communication integrated signal format. For example... Figure 4As shown, the inter-device transmission signal adopts orthogonal dual-path BPSK modulation. The I path is a low-speed data frame, using spread spectrum plus BPSK modulation, mainly used for spread spectrum ranging and velocimetry, and also for transmitting low-speed measurement data. The typical data rate is 1kbps to 10kbps. The Q path is a high-speed data frame, using BPSK modulation, used for transmitting high-speed communication data between the devices. Due to the system's transmit / receive switching, the received signal is unstable at the moment of switching, with a typical time on the order of 1µs. This can easily cause interference to the start data bits of the high-speed data frame, but the interference to the start data of the low-speed data frame is negligible. Therefore, no independent additional synchronization word is set at the beginning of the high-speed data frame. During this period, the received data of the Q path is invalid until the additional synchronization word of the I path ends, at which point the demodulation of the Q path data begins. The carrier phases of the I and Q paths are orthogonal to each other, the frame headers are aligned, and the data rates are integer multiples of each other. The typical rate can vary between 10kbps and 10Mbps depending on the operating distance. In actual rendezvous and docking processes, it can be used to transmit voice and image data.

[0053] The forward and reverse link frequencies of aircraft A and B are the same, both in the Ka band. When aircraft C is added during a flight mission, the same Ka band is also used. Specifically, based on the antenna configuration of aircraft C, four configurations can be formed: "A with radar antenna - C with transponder antenna", "A with radar antenna - C with radar antenna", "B with transponder antenna - C with transponder antenna", and "B with transponder antenna - C with radar antenna". Among them, the configurations "A with radar antenna - C with transponder antenna" and "B with transponder antenna - C with radar antenna" are... Figure 1 The basic configuration is the same; the "A with radar antenna - C with radar antenna" configuration is as follows: Figure 5 As shown, in this scenario, both aircraft are equipped with phased array antennas. Depending on mission requirements, one end can be designated as a transponder. Before the link is established, servo control and beam control signals are sent via the radar processor. A broadened beam is formed on the phased array antenna at the transponder end for the other end's radar to scan, acquire, and track. Once the tracking link is established, time-division multiplexing measurements and communication can be performed. The configuration of "B with transponder antenna - C with transponder antenna" is as follows: Figure 6 As shown, in this scenario, both aircraft are equipped with wide-beam multi-element antennas. Depending on mission requirements, one end can be designated as the radar end. Since both ends are wide-beam antennas, the antenna scanning and acquisition process can be skipped, allowing direct time-division multiplexing measurements and communication. Furthermore, when the antenna configuration changes according to mission requirements, since the frequency points are the same, the radar and transponder hardware can be modified without altering the backend processing via software definition. This eliminates the need to consider frequency pairing issues or hardware compatibility problems when two or more aircraft are docked for measurements, thus expanding the flexibility of rendezvous and docking missions.

[0054] The contents not described in detail in this specification are common knowledge to those skilled in the art.

[0055] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A long-range microwave rendezvous radar system integrating time-division measurement and communication, characterized in that, include: Microwave radar, microwave transponder; The microwave radar and microwave transponder are each installed on one aircraft; Microwave radar includes a radar antenna and a radar main unit; The radar antenna includes a one-dimensional electronically scanned phased array antenna and a one-dimensional servo mechanism. The phased array antenna adopts a design that allows for both receiving and transmitting on the same array surface, and it can transmit and receive radio frequency signals at the same frequency in a time-division multiplexing manner. The radar host includes a radar transceiver channel and a radar processor. The radar transceiver channel converts the received radio frequency signal into the received intermediate frequency signal and the transmitted intermediate frequency signal into the transmitted radio frequency signal. The radar processor generates servo and beam control signals for the servo mechanism and phased array antenna, and simultaneously transmits, receives, processes, and calculates the radar intermediate frequency signal to obtain ranging, velocity, angle measurement, and communication information. A microwave transponder includes a transponder antenna and a transponder main unit. The transponder antenna is a wide-angle interferometer antenna, which includes a set of array elements and a multiplexer switch. The array elements are selected in a time-division multiplexing manner through the multiplexer switch and transmit and receive radio frequency signals at the same frequency. The transponder host includes a transponder transceiver channel and a transponder processor. The transponder transceiver channel converts received radio frequency signals into received intermediate frequency signals and transmits intermediate frequency signals into transmitted radio frequency signals. The transponder processor generates a selection signal for the antenna multiplexer switch, and simultaneously transmits, receives, processes, and calculates the intermediate frequency signal of the transponder to generate ranging, speed, angle measurement, and communication information. The radar antenna adopts a one-dimensional mechanical scanning plus one-dimensional phase scanning antenna mode to meet the system's requirements for large-angle and long-range operation, while using a single-pulse angle tracking method to obtain the angle measurement value. Transponder antennas can form wide-angle coverage, and angle values ​​are obtained through interferometric angle measurement.

2. The remote microwave rendezvous radar system of claim 1, wherein, The ranging value is obtained by transmitting and receiving time-division coherent relay ranging method at both ends of the aircraft; the velocity value is obtained by transmitting and receiving time-division coherent relay Doppler velocity measurement method at both ends.

3. The remote microwave rendezvous radar system of claim 1, wherein, Communication is achieved at both ends through an integrated measurement and communication signal format; the long-range microwave rendezvous radar system can perform ranging, speed measurement, angle measurement and communication on both ends of the aircraft.

4. The remote microwave rendezvous radar system of claim 1, wherein, This long-range microwave rendezvous radar system employs a time-division coherent ranging method for ranging, as detailed below: Assume that the microwave radar is installed on aircraft A and the microwave transponder is installed on aircraft B; The inter-vehicle ranging signal between aircraft A and aircraft B includes a transmission time slot and a reception time slot. The basic unit of each time slot is one spreading code period. One spreading code period is greater than twice the maximum inter-vehicle signal transmission delay T. Each aircraft's transmission time slot consists of N spreading code periods, and each aircraft's reception time slot consists of N+1 spreading code periods. The extra spreading code period in the reception time slot is used to wait for the inter-vehicle transmission delay. When spacecraft A acts as the active ranging terminal, it transmits a forward inter-range ranging frame consisting of N spreading code cycles. After an inter-vehicle signal transmission delay T, spacecraft B receives the forward inter-range ranging frame from spacecraft A. Spacecraft B performs spreading code tracking and demodulation. After receiving the forward inter-range ranging frame consisting of N spreading code cycles, it enters the transmission time slot, maintains open-loop spreading code tracking during the transmission time slot, and forwards the tracked and regenerated spreading code. It then transmits a reverse inter-range ranging frame consisting of N spreading code cycles. After an inter-vehicle transmission delay T, spacecraft A receives the reverse inter-range ranging frame transmitted by spacecraft B. According to the inter-vehicle transmission process, the time difference between the end of the forward inter-range ranging frame from spacecraft A and the beginning of the reverse inter-range ranging frame from spacecraft B is... The inter-vehicle transmission delay T is twice that of spacecraft A, measured at the A end. The inter-vehicle transmission delay T can then be calculated, thus yielding the distance R between the two aircraft. The basic calculation formula is shown below: wherein denotes the speed of light, denotes the inter-device transmission delay, denotes the time difference between the emission of the frame tail and the reception of the frame head.

5. The remote microwave rendezvous radar system of claim 4, wherein, The ranging value R obtained by spacecraft A is used as inter-space communication data. After data modulation, it is transmitted to spacecraft B along with the inter-space ranging frame. Spacecraft B performs spread spectrum tracking demodulation on the spreading code, thereby solving the inter-space distance in spacecraft B.

6. The remote microwave rendezvous radar system of claim 1, wherein, This long-range microwave rendezvous radar system uses a time-division multiplexing coherent relay Doppler velocity measurement method for velocity measurement, as detailed below: Assume that the microwave radar is installed on aircraft A and the microwave transponder is installed on aircraft B; When aircraft A acts as an active velocity measuring terminal, it transmits a carrier-modulated signal with the same duration as the ranging frame between the forward probes, at a frequency of [frequency value missing]. After the inter-device transmission delay T and the added velocity Doppler frequency shift Subsequently, spacecraft B received a forward ranging frame from spacecraft A at a frequency of [frequency missing]. The B-type aircraft tracks and demodulates the carrier modulation signal. After receiving a signal with the same duration as the ranging frame between the forward probes, it enters the transmission time slot. During the transmission time slot, it maintains open-loop carrier tracking and forwards the regenerated carrier at a transmission frequency of [frequency missing]. The transmission duration is the same as the inter-reverse ranging frame, after which an inter-reverse transmission delay T is added and a velocity Doppler frequency shift is applied again. Subsequently, spacecraft A received the inter-reverse ranging frame transmitted by spacecraft B, with a receiving frequency of [frequency missing]. According to the inter-vehicle transmission procedure, the frequency difference between the frequency of the forward inter-vehicle ranging frame transmitted by spacecraft A and the frequency of the received reverse inter-vehicle ranging frame is... At the A aircraft end, frequency difference Duration is The points, every time The first Doppler integral phase value is obtained. By taking the difference between them, the speed between the two aircraft can be calculated. .

7. The remote microwave rendezvous radar system of claim 6, wherein, The speed value obtained by the aircraft As inter-vehicle communication data, the data is modulated and transmitted to the B aircraft with the inter-vehicle ranging frame, the B aircraft performs spread spectrum code tracking demodulation, and thus the inter-vehicle speed is solved at the B aircraft.

8. The remote microwave rendezvous radar system of claim 1, wherein, This long-range microwave rendezvous radar system adopts a time-division multiplexing measurement and communication integrated signal format, specifically: The inter-device transmission signal adopts orthogonal dual-channel BPSK modulation. The I channel is a low-speed data frame, which adopts spread spectrum plus BPSK modulation and is used for spread spectrum ranging and velocity measurement, and also for transmitting low-speed measurement data. The Q channel is a high-speed data frame, which adopts BPSK modulation and is used for transmitting high-speed communication data between the devices. No independent additional synchronization word is set at the beginning of the high-speed data frame. During this period, the received data of the Q channel is invalid until the additional synchronization word of the I channel ends, and the demodulation of the Q channel data begins. The I and Q carrier phases are orthogonal to each other, the frame headers are aligned, and the data rates are integer multiples of each other.

9. The remote microwave rendezvous radar system of any one of claims 1 to 8, wherein, Assume the microwave radar is installed on aircraft A, and the microwave transponder is installed on aircraft B; when aircraft C needs to be added during the flight mission, the following method will be used: Based on the antenna configuration of aircraft C, one of four configurations can be formed: A with radar antenna-C with transponder antenna, A with radar antenna-C with radar antenna, B with transponder antenna-C with transponder antenna, and B with transponder antenna-C with radar antenna. The configurations of A with radar antenna - C with transponder antenna and B with transponder antenna - C with radar antenna are the same as those of A with radar antenna - B with transponder antenna. When configuring the radar antenna configuration A-C, one end is defined as the transponder. Before the link is established, the radar processor sends servo control and beam control signals to form a broadened beam on the phased array antenna at the defined transponder end, which is then scanned, captured, and tracked by the radar at the other end. After the tracking link is established, time-division multiplexing measurement and communication can be performed. When configuring transponder antenna B-C, one end is defined as the radar end, and time-division multiplexing measurement and communication are performed directly.

10. A measurement and communication method based on a long-range microwave rendezvous radar system according to any one of claims 1 to 8, characterized in that, include: Microwave radar uses a single-pulse angle tracking method to obtain angle measurement values; Microwave transponders obtain angle values ​​through interferometric angle measurement; The two aircraft acquire ranging values ​​through a time-division coherent relay ranging method. The two aircraft obtained velocity values ​​through a time-division coherent relay Doppler velocity measurement method.

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