A method, device and system for automatic multi-channel switching of an aircraft measurement and control station

Abstract

The present invention discloses a method, device and system for automatic multi-channel switching of an aircraft measurement and control station, including the following steps: taking the relative position relationship between the aircraft and the ground measurement and control station as a reference, dividing the flight attitude of the aircraft into three states; formulating a reasonable and feasible ground antenna channel receiving and transmitting combination scheme according to the flight trajectory of the aircraft at each stage, the functions and performance characteristics of various ground antennas, and the environmental factors around the station site, and automatically switching to the ground antenna channel receiving and transmitting combination in the corresponding flight state to complete the measurement and control task when performing the measurement and control task. The present invention can realize the advanced configuration, reasonable layout, no signal blind spot, automatic switching and seamless relay of signal channels of multiple sets of aircraft ground antennas or terminals, meet the uplink and downlink signal transmission or communication requirements between the aircraft and the ground measurement and control station, and improve the operating efficiency of the ground telemetry and remote control system.

Description

Technical Field

[0001] The present invention belongs to the technical field of aviation vehicle telemetry and remote control, and in particular relates to a multi-channel automatic switching method, device and system for an aviation vehicle measurement and control station. Background Art

[0002] The application of ground telemetry and remote control of aircraft is to understand and grasp the flight parameters and status of aircraft in real time and ensure uninterrupted signal transmission between aircraft and ground. On the other hand, it can ensure the safety of aircraft and personnel at critical moments. As the telemetry and remote control technology of aircraft becomes more and more mature, various advanced technologies and equipment have been widely used, but there are still signal blind spots, low system integration and automation.

[0003] Through investigation, it is found that in the application cases using a single antenna or a single terminal, in order to transmit and interact more information with the flying target, the only antenna of the ground tracking and control station is usually set up on a platform with a certain height, such as: on the roof of a building or on the roof of a car. Therefore, the tracking and control station antenna has a very low pitch angle for the tracking and control of the aircraft, and the lowest pitch angle can generally reach about -5°. For the high-gain transmitting and receiving antennas of the needle beam, a too low pitch angle will produce multipath effects, deteriorate the signal quality, and affect the tracking and control effect. When the target flies over the head of the tracking and control station, if the tracking and control station antenna does not have the ability to track over the top, it will not be able to receive the signal normally, resulting in serious consequences such as signal interruption and target loss. Different buildings near the tracking and control station will also cause signal obstruction, and there will be antenna radiation blind spots, resulting in signal interruption. In addition, due to the single type and limited number of antennas, the overall function of the system will be imperfect. Therefore, in the application environment using a single antenna or a single terminal, there are problems such as signal radiation blind spots, signal interruption, target loss, and imperfect system functions. In application cases using multiple antennas or multiple terminals, although some problems existing in single antennas or single terminals are avoided, there are still problems such as poor selection of antenna types, insufficient quantity ratio, unreasonable installation location, extended signal transmission time and low system automation. Summary of the invention

[0004] In order to completely solve the problems arising in the above two application modes and meet the needs of daily measurement and control business, the present invention discloses a multi-channel automatic switching method, device and system for an aircraft measurement and control station. The technical problem to be solved is achieved through the following technical solution.

[0005] The present invention discloses a multi-channel automatic switching method for an aircraft measurement and control station, comprising the following steps:

[0006] S1, based on the relative position relationship between the aircraft and the ground control station, the flight attitude of the aircraft is divided into three states;

[0007] S2, according to the flight trajectory of the aircraft at each stage, the functions and performance characteristics of various ground antennas, and the environmental factors around the site, formulate a reasonable and feasible ground antenna channel reception and transmission combination plan, so that when performing measurement and control tasks, it can automatically switch to the ground antenna channel reception and transmission combination under the corresponding flight state to complete the measurement and control tasks.

[0008] Preferably, in S1, the flight attitude of the aircraft is divided into three states, namely: take-off and landing stage, level flight stage, and overhead stage.

[0009] Preferably, in S2, according to the flight trajectory of the aircraft at each stage, the functions and performance characteristics of various ground antennas, and the environmental factors around the site, a reasonable and feasible ground antenna channel receiving and transmitting combination scheme is formulated as follows:

[0010] ⑴ The aircraft is in the take-off and landing phase

[0011] In this state, the wide beam directional antenna unit A and the wide beam directional antenna unit B receive telemetry data, and simultaneously amplify and compare the signals, and select the strongest one of the two signals for output; when the flight elevation angle ≤ α1, and the flight distance ≤ L kilometers, the wide beam directional antenna unit A or the wide beam directional antenna unit B works; when the flight elevation angle > α1, or the flight distance > L kilometers, the wide beam directional antenna unit A or B switches with the single reflector antenna unit;

[0012] While the downlink channel is working, the uplink channel is switched to the corresponding wide beam directional antenna unit A or wide beam directional antenna unit B or single reflector antenna unit, the uplink channel is officially opened, and the remote control command is transmitted;

[0013] Among them, α1 refers to the pitch angle between the aircraft and the wide beam directional antenna unit of the tracking and control station, and L refers to the maximum distance between the aircraft and the tracking and control station when the wide beam directional antenna unit is working and the tracking and control system can normally receive and analyze telemetry data;

[0014] ⑵The aircraft is in level flight

[0015] In this state, the wide beam directional antenna unit A, the wide beam directional antenna unit B, and the single reflector antenna unit can all receive telemetry data, and simultaneously amplify and compare the signals, and select the strongest one of the three signals for output; when β1>flight elevation angle>α1, the single reflector antenna unit mainly works to perform GPS guidance and tracking; when the flight elevation angle ≥ψ, the tracking mode of the single reflector antenna unit can be switched from GPS guidance and tracking to single pulse self-tracking mode;

[0016] While the downlink channel is working, the uplink channel is switched to the corresponding single reflector antenna unit, the uplink channel is officially opened, and the remote control command is transmitted;

[0017] Among them, β1 refers to the elevation angle of the single reflector antenna unit of the aircraft and the tracking and control station, ψ is θ+Φ, θ refers to the elevation beam angle of the radiation pattern of the single reflector antenna unit, and Φ refers to the safe angle at which the single reflector antenna unit can operate in the single pulse self-tracking mode;

[0018] ⑶ The aircraft is in the overhead phase

[0019] When the flight elevation angle is ≥β1, the single reflector antenna unit continues to work and the low noise amplifier in the antenna high frequency box works in low gain mode. At the same time, the signal level of the single reflector antenna unit and the hemispherical antenna unit are compared. By default, the single reflector antenna unit channel signal output is selected, and it is determined whether the single reflector antenna unit works abnormally when the aircraft is flying over the top. If the single reflector antenna unit works abnormally, the hemispherical antenna unit channel signal output is selected;

[0020] While the downlink channel is working, the uplink channel is switched to the corresponding single reflector antenna unit or hemispherical antenna unit, the uplink channel is officially opened, and the remote control command is transmitted.

[0021] Preferably, the threshold value L of the real-time distance between the aircraft and the tracking and control station needs to be determined in combination with the aircraft transmission EIRP, electromagnetic wave free space attenuation, receiving antenna G / T value and intermediate frequency receiver Eb / N0 system link budget.

[0022] The present invention discloses a multi-channel automatic switching device for an aircraft measurement and control station, the device comprising: a wide beam directional antenna unit A, a wide beam directional antenna unit B, a single reflector antenna unit, a hemispherical antenna unit, an optical fiber / optical terminal unit, a terminal selection unit, a down-conversion unit, an up-conversion unit, and a modulation and demodulation unit, wherein:

[0023] Wide beam directional antenna unit A and wide beam directional antenna unit B are used to complete the remote control command transmission and telemetry signal reception of low elevation angle and close-range targets;

[0024] The single reflector antenna unit is used to transmit remote control commands and receive telemetry signals for targets at long distances, high elevation angles, and overhead targets;

[0025] The hemispherical antenna unit is used to take over the single reflector antenna unit to complete the telemetry signal reception and remote control command transmission of the overhead target signal when the single reflector antenna unit malfunctions during the overhead flight of the target;

[0026] Optical fiber / optical terminal unit, used to realize remote deployment and signal transmission of various antenna units;

[0027] Terminal selection unit, used to complete the automatic selection and switching of uplink and downlink measurement and control signal channels;

[0028] A down-conversion unit, used for down-converting the radio frequency telemetry signal into an intermediate frequency telemetry signal and outputting the signal;

[0029] An up-conversion unit, used for up-converting the intermediate frequency remote control signal into a radio frequency remote control signal and outputting the signal;

[0030] The modulation and demodulation unit is used to complete the coding modulation of the uplink remote control commands and the demodulation and extraction of the downlink effective telemetry data.

[0031] Preferably, the wide beam directional antenna unit A and the wide beam directional antenna unit B are the same, are installed at different positions according to measurement and control requirements, and serve as backup units for each other.

[0032] Preferably, the single reflector antenna unit has an antenna mount in the form of a tilt-axis azimuth and elevation three-axis mount according to the requirements of antenna over-the-top measurement and control.

[0033] The present invention discloses a multi-channel automatic switching system for an aircraft measurement and control station, the system comprising the multi-channel automatic switching device for an aircraft measurement and control station as described above and a control center, wherein:

[0034] The control center is used to parse the GPS digital information in the telemetry data packet and obtain the target location information; output the antenna pointing command to complete GPS guidance tracking; output the channel selector channel switching command to complete the channel selection; execute the control instructions issued by the superior control center.

[0035] Preferably, the channel switching command of the control center has the channel switching instruction judgment criterion priority as follows: the flight pitch angle judgment level is higher than the flight distance, and the flight distance judgment level is higher than the signal level judgment level.

[0036] The beneficial effects of the present invention are: rationally designing the composition of the entire measurement and control system, scientifically arranging the installation location, improving the functions and optimizing the indicators of each main unit, so as to achieve an effect that both the single-machine capacity and the system capacity are superior to the existing ground measurement and control station system, among which:

[0037] The wide-beam directional antenna unit has the characteristics of wide bandwidth, wide beam, high gain, low standing wave and anti-interference; the antenna units A and B are reasonably laid out and back up each other, which greatly improves the measurement and control reliability of the measurement and control station at low elevation angles and close distances;

[0038] Single reflector antenna unit: It can realize the functions of transmitting and receiving multiple frequencies simultaneously, and has the capabilities of single pulse tracking, GPS data guidance, and memory tracking; it has the capabilities of 360° infinite rotation in azimuth and pitch over-the-top tracking of targets without losing them; it has the capabilities of high pointing accuracy and high tracking accuracy; it also has the characteristics of low standing waves, high gain, and low side lobes;

[0039] Terminal selection unit: It has the characteristics of high degree of channel switching automation and short switching time;

[0040] Measurement and control system: It has the characteristics of automatic switching between the uplink remote control signal channel and the downlink telemetry signal channel, seamless relay and uninterrupted signal transmission, high transmission efficiency and no target loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a flow chart of the steps of the method of the present invention;

[0042] Figure 2 A top view showing the types, quantities and installation positions of antenna units in the ground measurement and control station of the present invention;

[0043] Figure 3 It is a schematic diagram of the working principle of the tilt-axis azimuth / elevation triaxial mount of the single reflector antenna of the present invention;

[0044] Figure 4 It is the up / down air-to-ground signal link diagram of the present invention;

[0045] Figure 5 This is the system composition and signal flow diagram of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the present invention clearer and more understandable, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0047] The present invention discloses a multi-channel automatic switching method for an aircraft measurement and control station. Figure 1 As shown, the following steps are included:

[0048] S1, based on the relative position relationship between the aircraft and the ground control station, the flight attitude of the aircraft is divided into three states.

[0049] Based on the relative position relationship between the aircraft and the ground measurement and control station, the flight attitude of the aircraft is divided into three states: take-off and landing stage, level flight stage, and overhead stage.

[0050] S2, according to the flight trajectory of the aircraft at each stage, the functions and performance characteristics of various ground antennas, and the environmental factors around the site, formulate a reasonable and feasible ground antenna channel reception and transmission combination plan, so that when performing measurement and control tasks, it can automatically switch to the ground antenna channel reception and transmission combination under the corresponding flight state to complete the measurement and control tasks.

[0051] Under various flight conditions of the aircraft, a reasonable and feasible ground antenna channel receiving and transmitting combination scheme is formulated as follows:

[0052] ⑴ The aircraft is in the take-off and landing phase

[0053] In this state, wide beam directional antenna unit A and wide beam directional antenna unit B receive telemetry data, and simultaneously amplify and compare the signals, and select the strongest of the two signals for output; when the flight elevation angle ≤α1 and the flight distance ≤L kilometers, wide beam directional antenna unit A or wide beam directional antenna unit B works; when the flight elevation angle >α1, or the flight distance >L kilometers, wide beam directional antenna unit A or B switches with the single reflector antenna unit.

[0054] While the downlink channel is working, the uplink channel is switched to the corresponding wide beam directional antenna unit A or wide beam directional antenna unit B or single reflector antenna unit, the uplink channel is officially opened, and the remote control command is transmitted.

[0055] Among them, α1 refers to the pitch angle between the aircraft and the wide beam directional antenna unit of the tracking and control station. The specific threshold value of the switching angle needs to be determined in combination with the directional gain of the wide beam directional antenna. L refers to the maximum distance between the aircraft and the tracking and control station when the wide beam directional antenna unit is working and the tracking and control system can normally receive and analyze telemetry data. The threshold value of this distance needs to be determined in combination with the system link budget such as the aircraft's transmit EIRP, electromagnetic wave free space attenuation, receiving antenna G / T value and intermediate frequency receiver Eb / N0. The system link budget involves the free space loss formula: 32.4+20log(F)+20log(D), F is the frequency, unit: MHz, D is the straight-line distance between the target aircraft and the tracking and control station, unit: Km.

[0056] ⑵The aircraft is in level flight

[0057] In this state, the wide beam directional antenna unit A, the wide beam directional antenna unit B, and the single reflector antenna unit can all receive telemetry data, and simultaneously amplify and compare the signals, and select the strongest of the three signals for output; when β1>flight elevation angle>α1, the single reflector antenna unit mainly works to perform GPS guided tracking; when the flight elevation angle ≥ψ, the tracking mode of the single reflector antenna unit can be switched from GPS guided tracking to single pulse self-tracking mode.

[0058] While the downlink channel is working, the uplink channel is switched to the corresponding single reflector antenna unit, the uplink channel is officially opened, and the remote control command is transmitted.

[0059] Among them, β1 refers to the pitch angle of the single reflector antenna unit of the aircraft and the tracking and control station. The specific threshold value of the switching angle is determined by the working angle of the third axis tilt axis of the single reflector. ψ is θ+Φ, θ refers to the pitch angle (normal angle) of the radiation pattern of the single reflector antenna unit, and Φ refers to the safe angle at which the single reflector antenna can work in the single pulse self-tracking mode. Its value is greater than α1 and can be manually preset according to the actual tracking effect during the joint test of the aircraft and the tracking and control station.

[0060] ⑶ The aircraft is in the overhead phase

[0061] When the flight elevation angle is ≥β1, the single reflector antenna unit continues to work and the low noise amplifier in the antenna high frequency box works in low gain mode. At the same time, the signal level of the single reflector antenna unit and the hemispherical antenna unit are compared, and the single reflector antenna unit channel signal output is selected by default. It is also determined whether the single reflector antenna unit works abnormally when the aircraft is flying over the top. If the single reflector antenna unit works abnormally, the hemispherical antenna unit channel signal output is selected.

[0062] While the downlink channel is working, the uplink channel is switched to the corresponding single reflector antenna unit or hemispherical antenna unit, the uplink channel is officially opened, and the remote control command is transmitted.

[0063] The invention discloses a multi-channel automatic switching device for an aircraft measurement and control station. The device comprises: a wide beam directional antenna unit A, a wide beam directional antenna unit B, a single reflector antenna unit, a hemispherical antenna unit, an optical fiber / optical terminal unit, a terminal selection unit, a down-conversion unit, an up-conversion unit, and a modulation and demodulation unit.

[0064] In the ground control station, the types, quantity and installation positions of the antenna units of the device are as follows: Figure 2 As shown, wide beam directional antenna unit A and wide beam directional antenna unit B are products of the same model with the same functions and performances. They are installed in different positions according to measurement and control requirements and can serve as backup units for each other to complete remote control command transmission and telemetry signal reception for low elevation angle and close-range targets.

[0065] The single reflector antenna unit of the device of the present invention is a 1.8-meter single reflector antenna unit, which is used to complete the transmission of remote control commands and the reception of telemetry signals for targets at long distances, high elevation angles, and overhead targets. It is also used to display and report information on the antenna's azimuth / pitch / tilt axis working angle, tracking mode, and working status; display information on the distance and pitch angle between the target and the measurement and control station; display and report the tracking receiver's working frequency, AGC value, and locking status; display and report alarm information when the antenna is working abnormally; and execute various control commands issued by the control center. According to the requirements of overhead measurement and control of the antenna, the antenna mount is in the form of a tilt-axis azimuth and pitch three-axis mount, and its working principle diagram is shown in the figure. Figure 3As shown, since the direction of the target passing overhead is unknown, the tilt axis can achieve 360° azimuth rotation.

[0066] The hemispherical antenna unit is used to take over the single reflector antenna unit to complete the reception of telemetry signals and the transmission of remote control commands for overhead target signals when the single reflector antenna unit malfunctions during overhead flight.

[0067] Optical fiber / optical terminal unit is used to realize the remote deployment of various antenna units, complete the transmission of uplink and downlink signals between the wide-beam directional antenna unit and the control room; complete the transmission of uplink and downlink signals between the single-reflector antenna unit and the control room; complete the transmission of uplink and downlink signals between the hemispherical antenna unit and the control room.

[0068] The terminal selection unit is used to complete the automatic switching of four downlink telemetry signal channels; complete the automatic switching of four uplink remote control signal channels; complete the information reporting of channel switching status; realize the reporting of alarm information when the uplink and downlink channel signals are abnormal; and execute the switching control instructions issued by the control center.

[0069] The down-conversion unit is used to down-convert the radio frequency telemetry signal into an intermediate frequency telemetry signal and output it.

[0070] The up-conversion unit is used to up-convert the intermediate frequency remote control signal into a radio frequency remote control signal and output it.

[0071] The modulation and demodulation unit is used to complete the coding modulation of the uplink remote control commands and the demodulation and extraction of the downlink effective telemetry data.

[0072] The present invention discloses a multi-channel automatic switching system for an aircraft measurement and control station, the system comprising the multi-channel automatic switching device for the measurement and control station as described above and a control center.

[0073] The control center is used to parse the GPS digital information in the telemetry data packet and obtain the target location information; output antenna pointing commands to complete GPS guidance tracking; output channel selector channel switching commands to complete channel selection; and execute control instructions issued by the superior control center.

[0074] The key point of the multi-channel automatic switching system of the aircraft measurement and control station lies in the parameter selection of important equipment, mainly to clarify the pitch beam coverage range of each antenna unit.

[0075] The signal coverage range (working status) of wide beam directional antenna unit A and wide beam directional antenna unit B is: ±α (horizontal angle) in the elevation direction and within 360° in the azimuth direction. Among them, α refers to the elevation angle (horizontal angle) of the radiation pattern of wide beam directional antenna unit A and wide beam directional antenna unit B.

[0076] The signal coverage range (working status) of the single reflector antenna unit is: ±β (normal angle) in the elevation direction, within 360° in the azimuth direction, where β refers to the elevation angle achievable by the servo turntable.

[0077] The signal coverage range (working status) of the hemispherical antenna unit is: ±γ° (normal angle) in the elevation direction and 360° in the azimuth direction. Among them, γ refers to the elevation angle (normal angle) of the radiation pattern of the hemispherical antenna unit.

[0078] Combination Figure 4 The up / down air-to-ground signal link diagram shown and Figure 5 The system composition and signal flow diagram shown in the figure describe in detail the working process of the multi-channel automatic switching system of the aircraft measurement and control station:

[0079] Receiving telemetry signals and transmission process:

[0080] Wide beam directional antenna unit A and wide beam directional antenna unit B receive telemetry signals sent by aircraft through wide beam directional antennas with large angle and high gain. After filtering, limiting and amplification, the telemetry signals are transmitted from the far-end optical terminal to the near-end optical terminal in the control room.

[0081] The single reflector antenna unit receives the telemetry data packets sent by the aircraft, obtains the target's location information after being parsed by the control software of the control center, and calculates the antenna pointing information in combination with the local location information of the measurement and control station. The antenna control unit issues control instructions, and uses GPS guidance tracking or single pulse self-tracking or manual tracking to drive the azimuth, pitch and third-axis motors to drive the antenna to aim at the target, receive the telemetry signal sent by the target, and after filtering, limiting and amplifying, the telemetry signal is transmitted by the remote optical terminal to the near-end optical terminal in the control room;

[0082] The hemispherical antenna unit receives the telemetry signal sent by the target through a hemispherical antenna with a radiating hemispherical beam characteristic. After filtering, limiting and amplification, the telemetry signal is transmitted from the far-end optical terminal to the near-end optical terminal in the control room.

[0083] The optical fiber / optical terminal unit receives the downlink telemetry signal output by the antenna, converts the electrical signal into an optical signal through the optoelectronic module of the remote optical terminal, and transmits it to the near-end optical terminal through the N-core armored optical fiber. In the near-end optical terminal, the optical signal is converted into an electrical signal through the optoelectronic conversion module;

[0084] The terminal selection unit receives the four-channel telemetry signal output by the near-end optical terminal in the control room and enters the terminal selector. The selector judges the level value of the four-channel signal through its own detection and amplification circuit, and selects the maximum signal channel to output to the down converter. When the control center issues a channel level comparison control instruction, the channel level comparison control instruction is executed; when the control center issues a channel switching control instruction, the channel switching control instruction is executed;

[0085] The down-conversion unit receives the downlink RF telemetry signal output from the terminal selection unit, filters, amplifies and mixes the RF signal, and outputs the intermediate frequency telemetry signal to the modulation and demodulation unit;

[0086] The modem unit receives the intermediate frequency signal output from the down converter and performs matching filtering, clock recovery, carrier recovery and channel equalization.

[0087] Transmitting remote control signal and transmission process:

[0088] The modem unit performs interface data conversion, framing, encoding, intermediate frequency modulation and other processes on the uplink remote control command and outputs it to the upconverter;

[0089] The up-conversion unit receives the intermediate frequency modulation signal output from the modulation and demodulation unit, filters, amplifies and mixes the intermediate frequency modulation signal, and outputs the uplink radio frequency remote control signal to the terminal selection unit;

[0090] After the receiving channel of the terminal selection unit determines the antenna working unit, the transmitting channel switch component will automatically switch to the antenna unit channel with the same name as the receiving channel, receive the uplink remote control signal from the up-converted transmission, and output it to the near-end optical terminal;

[0091] The optical fiber / optical terminal unit receives the uplink remote control signal output by the terminal selector, converts the electrical signal into an optical signal through the optoelectronic module of the near-end optical terminal, and transmits it to the far-end optical terminal through the N-core armored optical fiber. In the far-end optical terminal, the optical signal is converted into an electrical signal through the optoelectronic conversion module;

[0092] Wide beam directional antenna unit A and wide beam directional antenna unit B receive the uplink remote control command signal transmitted from the remote optical terminal, amplify it through the power amplifier, and then radiate it through the wide beam directional antenna;

[0093] The single reflector antenna unit receives the uplink remote control command signal transmitted from the remote optical terminal, amplifies it through the power amplifier, and then radiates it through the feed source and the reflector in turn;

[0094] The hemispherical antenna unit receives the uplink remote control command signal transmitted from the remote optical terminal, amplifies it through the power amplifier, and then radiates it through the hemispherical antenna unit.

[0095] The control process of sending and receiving measurement and control signals:

[0096] The control center receives telemetry data packets and parses the target's location information, combines it with local location information, and calculates and outputs the working angles of the azimuth / pitch / tilt axes of the single reflector antenna, and issues instructions to drive the antenna to point to the target; the real-time distance between the station and the target is calculated based on the target's location information and the station's location information, and a channel switching instruction is given through background calculation and judgment; the pitch angle between the station and the target is calculated based on the target's location information and the station's location information, and a channel switching instruction is given through background calculation and judgment. The priority of the channel switching instruction judgment criteria is: the flight pitch angle judgment level is higher than the flight distance, and the flight distance judgment level is higher than the signal level judgment level.

[0097] There are two common forms of ground measurement and control stations for aircraft, namely fixed and mobile. The fixed type means that the antenna is installed on a fixed platform without displacement, and the mobile type means that the antenna is installed on a platform such as a cart or trailer. According to mission requirements, the antenna will be moved with the platform to a designated site. The present invention is applicable to both application environments.

[0098] Based on the fixed ground measurement and control station, the specific process of automatic switching of the signal channel of the ground measurement and control station when performing measurement and control tasks is described in detail:

[0099] ⑴ The aircraft is in the take-off and landing phase

[0100] The aircraft is powered on and sends telemetry data, and all equipment in the ground control station system is powered on. At this time, the terminal selector only performs detection and amplification comparison on the signals in the channels of the wide beam directional antenna unit A and the wide beam directional antenna unit B, and the single reflector antenna unit and the hemispherical antenna unit do not participate in the channel signal level comparison.

[0101] Observe whether there is a signal passing through the two channels of wide beam directional antenna unit A and wide beam directional antenna unit B in the terminal selector (set the signal threshold). If there is no signal in one of the channels, a warning will be issued (the indicator light flashes). If there is no signal in both channels, an alarm will be issued (the indicator light flashes + beeps), and the operator will check the test system. When at least one channel has a signal passing through, the signal levels of the two channels are compared, and the maximum signal is output to the modem. By checking the value of Eb / N0 on the modem display and the color change of the bar graph (green, yellow and red), it is determined whether the output signal of the channel is valid. At the same time, the terminal selector feeds back the channel status to the control center.

[0102] The control software of the control center parses the telemetry data packet to obtain the target location information. Combined with the location information of the local station, it guides the 1.8-meter single-reflector antenna unit to point to the target through calculation (the antenna is in GPS guidance and tracking mode). The operator monitors and checks whether the 1.8-meter single-reflector antenna unit is aligned with the target.

[0103] The measurement and control system is normal, the aircraft starts to take off, the terminal selector receives and outputs telemetry signals in real time, and reports the channel working status to the control center at the same time. The control center analyzes the target information and switches and judges based on the target pitch angle and distance:

[0104] When the target flight elevation angle ≤ α1 and the flight distance ≤ L kilometers, the wide beam directional antenna unit A or the wide beam directional antenna unit B works.

[0105] When the target flight elevation angle> α1, or the flight distance> L kilometers, the control center first calculates the target elevation angle or distance, determines that it should switch to the 1.8-meter single reflector antenna unit channel and executes the switching instruction, and sends the 1.8-meter single reflector antenna unit channel to the terminal selector to participate in the signal level comparison instruction. The three channel level values ​​of the wide beam directional antenna unit A, wide beam directional antenna unit B and 1.8-meter single reflector antenna unit in the terminal selector are compared, and the maximum signal is output (theoretically it should be the 1.8-meter single reflector antenna unit). At the same time, the channel status is reported to the control center, and the control center compares the terminal selector report result and the control center control software calculation result. If the two results are inconsistent, an alarm message is issued to attract the operator's attention to the antenna pointing and signal locking status, and the operation log is saved.

[0106] While the downlink channel is working, the terminal selector uplink switch automatically switches the uplink channel to the corresponding antenna, wide beam directional antenna unit A or wide beam directional antenna unit B. The uplink channel is officially opened and the remote control command is transmitted. If the uplink channel is abnormal, the fault is reported at the same time.

[0107] ⑵The aircraft is in level flight

[0108] In this state, the wide beam directional antenna unit A, wide beam directional antenna unit B and 1.8m single reflector antenna unit can all receive telemetry data sent by the aircraft, and enter the terminal selector at the same time to detect, amplify and compare the three signals, and select the strongest one of the three signals for output (theoretically, it should be the 1.8m single reflector antenna unit). At this time, the channel status of the channel selector will also be fed back to the control center, and the control center will judge the reported channel working status with the resolved target elevation angle. The control center compares the terminal selector report result with the control center calculation result. If the two results are inconsistent, an alarm message will be issued to attract the operator's attention to the antenna pointing and signal locking status, and the operation log will be saved.

[0109] When β1>flight elevation angle>α1, the 1.8-meter single reflector antenna unit works, and the GPS data packet is received by the 1.8-meter single reflector antenna unit and sent to the control room.

[0110] When the flight elevation angle is ≥ψ, the tracking mode of the 1.8-meter single-reflector antenna unit can be switched from GPS-guided tracking to single-pulse self-tracking mode.

[0111] While the downlink channel is working, the terminal selector uplink switch automatically switches the uplink channel to the corresponding 1.8m single reflector antenna unit, and the uplink channel is officially opened to transmit remote control commands. If the uplink channel is abnormal, the fault will be reported at the same time.

[0112] ⑶ The aircraft is in the overhead phase

[0113] When the target's flight elevation angle is ≥ β1, the 1.8-meter single reflector antenna unit continues to work and ensures stable tracking of the target and data reception without loss when the target passes overhead. At this time, the control software of the control center calculates that the target's flight elevation angle is ≥ β1, and the distance between the aircraft and the measurement and control station is relatively close. In order to avoid excessive antenna reception signals, the control center immediately issues a gain shift instruction to the low noise amplifier in the high-frequency box of the 1.8-meter single reflector antenna unit, and makes the low noise amplifier work in a low gain state. At the same time, the control center will issue a hemispherical antenna unit channel signal level calculation instruction to the terminal selector to complete the comparison calculation of the signal level of the hemispherical antenna unit channel in the terminal selector and the signal level of the 1.8-meter single reflector antenna unit channel when the target passes overhead. The 1.8-meter single reflector antenna unit is selected by default. The two channel level values ​​of the wide beam directional antenna unit A and the wide beam directional antenna unit B are not involved in the comparison.

[0114] The control center first calculates the target elevation angle, determines based on the channel switching priority that the terminal selector should switch to the 1.8-meter single reflector antenna unit channel, and executes the switching command. Since the 1.8-meter single reflector antenna unit is already working when the target flight elevation angle>α1, the original state of the channel is maintained and no new switching command is executed. When the aircraft is working in the overhead state, the signal level value of the 1.8-meter single reflector antenna unit channel is less than the hemispherical antenna unit channel level value or there is no signal, the 1.8-meter single reflector antenna unit is judged to be abnormal. At this time, the control center issues a command to switch the hemispherical antenna unit channel, the hemispherical antenna unit works, and the control center issues an alarm message to attract the attention of the operator, and checks the antenna pointing and signal locking status, and saves the operation log.

[0115] While the downlink channel is working, the terminal selector uplink switch automatically switches the uplink channel to the corresponding antenna, 1.8m single reflector antenna unit or hemispherical antenna unit, and the uplink channel is officially opened to transmit remote control commands. If the uplink channel is abnormal, the fault will be reported at the same time.

Claims

1. A multi-channel automatic switching method for an aircraft measurement and control station, characterized in that: The following steps are involved: S1, based on the relative position relationship between the aircraft and the ground control station, the flight attitude of the aircraft is divided into three states: take-off and landing stage, level flight stage, and overhead stage; S2. According to the flight trajectory of the aircraft in the three stages, the functions and performance characteristics of various ground antennas, and the environmental factors around the site, a reasonable and feasible ground antenna channel receiving and transmitting combination plan is formulated. When performing measurement and control tasks, it can automatically switch to the ground antenna channel receiving and transmitting combination in the corresponding flight state to complete the measurement and control tasks. The reasonable and feasible ground antenna channel receiving and transmitting combination plan is formulated as follows: ⑴ The aircraft is in the take-off and landing phase In this state, the wide beam directional antenna unit A and the wide beam directional antenna unit B receive telemetry data, and simultaneously amplify and compare the signals, and select the strongest one of the two signals for output; when the flight elevation angle ≤ α1, and the flight distance ≤ L kilometers, the wide beam directional antenna unit A or the wide beam directional antenna unit B works; when the flight elevation angle > α1, or the flight distance > L kilometers, the wide beam directional antenna unit A or B switches with the single reflector antenna unit; While the downlink channel is working, the uplink channel is switched to the corresponding wide beam directional antenna unit A or wide beam directional antenna unit B or single reflector antenna unit, the uplink channel is officially opened, and the remote control command is transmitted; Among them, α1 refers to the pitch angle between the aircraft and the wide beam directional antenna unit of the tracking and control station, and L refers to the maximum distance between the aircraft and the tracking and control station when the wide beam directional antenna unit is working and the tracking and control system can normally receive and analyze telemetry data; ⑵The aircraft is in level flight In this state, the wide beam directional antenna unit A, the wide beam directional antenna unit B, and the single reflector antenna unit can all receive telemetry data, and simultaneously amplify and compare the signals, and select the strongest one of the three signals for output; when β1>flight elevation angle>α1, the single reflector antenna unit works and performs GPS guidance tracking; when the flight elevation angle ≥ψ, the tracking mode of the single reflector antenna unit can be switched from GPS guidance tracking to single pulse self-tracking mode; While the downlink channel is working, the uplink channel is switched to the corresponding single reflector antenna unit, the uplink channel is officially opened, and the remote control command is transmitted; Among them, β1 refers to the elevation angle of the single reflector antenna unit of the aircraft and the tracking and control station, ψ is θ+Φ, θ refers to the elevation beam angle of the radiation pattern of the single reflector antenna unit, and Φ refers to the safety angle of the single reflector antenna unit working in the single pulse self-tracking mode; ⑶ The aircraft is in the overhead phase When the flight elevation angle is ≥β1, the single reflector antenna unit continues to work and the low noise amplifier in the antenna high frequency box works in low gain mode. At the same time, the signal level of the single reflector antenna unit and the hemispherical antenna unit are compared. By default, the single reflector antenna unit channel signal output is selected, and it is determined whether the single reflector antenna unit works abnormally when the aircraft is flying over the top. If the single reflector antenna unit works abnormally, the hemispherical antenna unit channel signal output is selected; While the downlink channel is working, the uplink channel is switched to the corresponding single reflector antenna unit or hemispherical antenna unit, the uplink channel is officially opened, and the remote control command is transmitted.

2. An automatic multi-channel switching device for an aircraft measurement and control station, characterized in that: The device includes: a wide beam directional antenna unit A, a wide beam directional antenna unit B, a single reflector antenna unit, a hemispherical antenna unit, an optical fiber, a remote optical terminal and a near-end optical terminal in a control room, a terminal selection unit, a down-conversion unit, an up-conversion unit, and a modulation and demodulation unit, wherein: Wide beam directional antenna unit A and wide beam directional antenna unit B are used to complete the remote control command transmission and telemetry signal reception of low elevation angle and close-range targets; The single reflector antenna unit is used to transmit remote control commands and receive telemetry signals for targets at long distances, high elevation angles, and overhead targets; The hemispherical antenna unit is used to take over the single reflector antenna unit to complete the telemetry signal reception and remote control command transmission of the overhead target signal when the single reflector antenna unit malfunctions during the overhead flight of the target; Optical fiber, remote optical terminal and control room near-end optical terminal are used to realize remote deployment and signal transmission of various antenna units; The terminal selection unit is used to automatically select and switch uplink and downlink measurement and control signal channels during the take-off and landing phases, level flight phase, and overhead phase of the aircraft; A down-conversion unit, used for down-converting the radio frequency telemetry signal into an intermediate frequency telemetry signal and outputting the signal; An up-conversion unit, used for up-converting the intermediate frequency remote control signal into a radio frequency remote control signal and outputting the signal; The modulation and demodulation unit is used to complete the coding and modulation of the uplink remote control commands and the demodulation and extraction of the downlink effective telemetry data; The connection relationship of the above devices from top to bottom is: the wide beam directional antenna unit A, the wide beam directional antenna unit B, the single reflector antenna unit and the hemispheric antenna unit are connected to the remote optical terminal through the RF cable, the remote optical terminal is connected to the near-end optical terminal in the control room through the optical fiber, the near-end optical terminal in the control room is connected to the terminal selection unit through the RF cable, the terminal selection unit is connected to the down-conversion unit and the up-conversion unit respectively through the RF cable, and the down-conversion unit and the up-conversion unit are connected to the modulation and demodulation unit through the RF cable.

3. The multi-channel automatic switching device for an aircraft control station according to claim 2, characterized in that: The wide beam directional antenna unit A and the wide beam directional antenna unit B are the same, are installed at different positions according to measurement and control requirements, and serve as backup units for each other.

4. The multi-channel automatic switching device for an aircraft control station according to claim 2, characterized in that: The single reflector antenna unit has an antenna mount in the form of a tilt-axis azimuth and elevation three-axis mount according to the antenna over-the-top measurement and control requirements.

5. An automatic multi-channel switching system for an aircraft measurement and control station, characterized in that: It comprises the multi-channel automatic switching device of the aircraft control station as described in any one of claims 2-4, which enables the control station to automatically switch to the corresponding signal channel for signal transmission and reception when the aircraft is in different flight phases.

6. The multi-channel automatic switching system of an aircraft control station according to claim 5, characterized in that: The system also includes a control center, wherein: The control center is connected to the terminal selection unit to parse the GPS digital information in the telemetry data packet and obtain the target location information; output antenna pointing commands to complete GPS guidance tracking; output channel switching commands to complete the selection of different antenna channels of the terminal selection unit; and execute the control instructions issued by the superior control center.

7. The multi-channel automatic switching system of an aircraft measurement and control station according to claim 6, characterized in that: The channel switching command judgment criterion priority output by the control center is: the flight pitch angle judgment level is higher than the flight distance, and the flight distance judgment level is higher than the signal level judgment level.

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