Channel parameter calculation method of unmanned aerial vehicle simulation satellite

Abstract

The invention provides a channel parameter calculation method for an unmanned aerial vehicle simulation satellite, and belongs to the technical field of spaceflight measurement and control. The method comprises the following steps: constructing a system model for simulating satellite operation by the unmanned aerial vehicle, wherein the system model comprises a ground measurement and control station, the unmanned aerial vehicle and a to-be-simulated satellite; position information of a ground measurement and control station is determined, satellite track information of a satellite to be simulated is obtained, and meanwhile flight track information of the unmanned aerial vehicle is obtained; respectively calculating the satellite radial speed of the to-be-simulated satellite relative to the ground measurement and control station and the unmanned aerial vehicle radial speed of the unmanned aerial vehicle relative to the ground measurement and control station by using the position information, the satellite track information and the flight track information of the ground measurement and control station; and calculating channel parameters of the system model by using the satellite track information, the flight track information, the satellite radial speed and the unmanned aerial vehicle radial speed. According to the invention, the simulation effect of the satellite channel is more vivid, and the calculation error caused by the satellite operation deviation is effectively reduced.

Description

Technical Field

[0001] The present application relates to the field of aerospace measurement and control technology, and in particular to a method for calculating channel parameters of a UAV simulating a satellite. Background Art

[0002] In the field of aerospace tracking and control technology, ground tracking and control stations cannot systematically cooperate with ground tracking and control stations for long-term training and testing due to factors such as limited resources, high safety risks, and limited transit times of orbiting satellites. Therefore, it is necessary to use drones equipped with tracking and control transponders to simulate the transit of orbiting satellites and establish a tracking and control link with ground tracking and control stations that is similar to that of orbiting satellites. When a drone simulates an orbiting satellite, it must always be in the tracking and control link between the orbiting satellite and the ground tracking and control station. To ensure the simulation effect is realistic, velocity equivalence is required, so that the radial velocity of the drone measured by the ground tracking and control station is equal to the radial velocity of the actual orbiting satellite.

[0003] Currently, when performing velocity equivalence, a channel simulator is generally used to compensate for the uplink or downlink pseudo-Doppler values using the actual signal frequency offset. This allows the ground tracking station's calculated velocity to be consistent with that of the in-orbit satellite, thus achieving velocity equivalence. However, current channel simulators for various satellites are mostly static ground-based applications. When calculating channel parameters, they only consider the ground tracking station and the simulated satellite. In scenarios where drones are used to simulate satellites, the channel simulator moves with the drone. Therefore, this static ground-based application ignores the need to consider the drone's motion when calculating channel parameters.

[0004] Therefore, it is necessary to propose a solution to improve one or more problems existing in the above-mentioned related technical solutions.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0006] The present invention provides a method for calculating channel parameters of a simulated satellite using a drone, the method comprising the following steps:

[0007] Constructing a system model for the UAV to simulate satellite operation, the system model includes a ground tracking and control station, a UAV, and a satellite to be simulated; the UAV is always located on a tracking and control link between the ground tracking and control station and the satellite to be simulated, the tracking and control link including an uplink and a downlink;

[0008] Determine the location information of the ground measurement and control station, obtain the satellite trajectory information of the satellite to be simulated, and simultaneously obtain the flight trajectory information of the UAV;

[0009] Calculate the satellite radial velocity of the simulated satellite relative to the ground measurement and control station and the UAV radial velocity of the UAV relative to the ground measurement and control station using the position information of the ground measurement and control station, the satellite trajectory information, and the flight trajectory information;

[0010] Calculating channel parameters of the system model using the satellite trajectory information, the flight trajectory information, the satellite radial velocity, and the UAV radial velocity;

[0011] The channel parameters include a delay adjustment amount, an attenuation adjustment amount, and a Doppler frequency shift adjustment amount of the analog downlink signal from the UAV to the ground measurement and control station.

[0012] Furthermore, the UAV is equipped with a measurement and control transponder and a channel simulator; the uplink includes a simulated uplink signal from the ground measurement and control station to the UAV, and an actual uplink signal from the ground measurement and control station to the satellite to be simulated; the downlink includes the simulated downlink signal from the UAV to the ground measurement and control station, and an actual downlink signal from the satellite to be simulated to the ground measurement and control station.

[0013] Furthermore, the steps of determining the position information of the ground measurement and control station, obtaining the satellite trajectory information of the satellite to be simulated, and simultaneously obtaining the flight trajectory information of the UAV include:

[0014] Calculating the satellite trajectory information according to the orbital elements of the satellite to be simulated;

[0015] Acquiring the flight trajectory information according to the real-time positioning information of the UAV during flight, and performing smoothing processing on the flight trajectory information;

[0016] Determine the location information of the ground measurement and control station.

[0017] Furthermore, the satellite trajectory information includes position information and speed information of the satellite to be simulated; and the flight trajectory information includes position information and speed information of the UAV.

[0018] Furthermore, the step of calculating the satellite radial velocity of the satellite to be simulated relative to the ground measurement and control station and the UAV radial velocity of the UAV relative to the ground measurement and control station by using the position information of the ground measurement and control station, the satellite trajectory information, and the flight trajectory information includes:

[0019] Converting the satellite trajectory information, the flight trajectory information, and the position information of the ground measurement and control station into the same coordinate system;

[0020] Calculating the satellite radial velocity based on the satellite trajectory information and the position information of the ground measurement and control station;

[0021] The radial velocity of the UAV is calculated based on the flight trajectory information and the position information of the ground measurement and control station.

[0022] Furthermore, the step of calculating the channel parameters of the system model using the satellite trajectory information, the flight trajectory information, the satellite radial velocity, and the UAV radial velocity includes:

[0023] Calculating the delay adjustment amount of the simulated downlink signal according to the difference between the distance between the simulated satellite and the ground measurement and control station and the distance between the UAV and the ground measurement and control station;

[0024] Calculating the attenuation adjustment amount of the simulated downlink signal by using the transmission power of the actual downlink signal and the simulated downlink signal;

[0025] Setting the frequency of the simulated downlink signal to be equivalent to the frequency of the actual downlink signal, and calculating the coherent Doppler frequency shift adjustment amount of the simulated downlink signal when the ground measurement and control station performs coherent velocity measurement;

[0026] Making the speed information of the UAV measured by the ground measurement and control station equivalent to the speed information of the simulated satellite measured by the ground measurement and control station, and calculating the incoherent Doppler frequency shift adjustment amount of the simulated downlink signal when the ground measurement and control station performs incoherent speed measurement;

[0027] The Doppler frequency shift adjustment amount includes the coherent Doppler frequency shift adjustment amount and the incoherent Doppler frequency shift adjustment amount.

[0028] Furthermore, the step of calculating the delay adjustment amount of the simulated downlink signal according to the difference between the distance between the simulated satellite and the ground measurement and control station and the distance between the UAV and the ground measurement and control station includes:

[0029] Calculating a first distance from the satellite to be simulated to the ground measurement and control station according to the position information of the satellite to be simulated in the coordinate system and the position information of the ground measurement and control station;

[0030] Calculating a second distance from the UAV to the ground measurement and control station based on the position information of the UAV in the coordinate system and the position information of the ground measurement and control station;

[0031] Calculating a distance difference between the first distance and the second distance;

[0032] Making the ranging result of the ground measurement and control station for the UAV equivalent to the ranging result of the ground measurement and control station for the simulated satellite, and calculating the delay adjustment amount of the simulated downlink signal using the distance difference;

[0033] The expression of the delay adjustment amount of the simulated downlink signal is:

[0034]

[0035] Among them, Δt represents the delay adjustment of the analog downlink signal, R Satellite Indicates the first distance from the simulated satellite to the ground tracking station, R UAV represents the second distance from the UAV to the ground tracking and control station, and c represents the speed of light.

[0036] Furthermore, the step of calculating the attenuation adjustment amount of the simulated downlink signal by using the transmission power of the actual downlink signal and the simulated downlink signal includes:

[0037] Calculating a first transmission power of the actual downlink signal;

[0038] The expression of the first transmission power is:

[0039] P 1-Ground =P Satellite -L Los_Satellite -L Air_Satellite (2)

[0040] Among them, P 1-Ground Indicates the first transmission power of the actual downlink signal, P Satellite Indicates the equivalent radiated power of the actual downlink signal, L Los_Satellite Indicates the propagation loss of the satellite signal to be simulated in free space, L Los_Satellite =32.44+20lgf 实际 +20lgR Satellite , f 实际 Indicates the frequency of the equivalent signal of the actual downlink signal, R Satellite Indicates the first distance from the simulated satellite to the ground tracking station, L Air_Satellite represents the atmospheric loss of the signal from the satellite to be simulated as it passes through the atmosphere;

[0041] Calculating a second transmission power of the simulated downlink signal;

[0042] The expression of the second transmission power is:

[0043] P 2-Ground =P UAV -ΔL-L Los_UAV -L Air R UAV (3)

[0044] Among them, P 2-Ground represents the second transmission power of the simulated downlink signal, P UAV It represents the equivalent radiated power of the simulated downlink signal, ΔL represents the attenuation adjustment of the simulated downlink signal, L Los_UAV represents the propagation loss of the UAV signal in free space, L Los_UAV =32.44+20lgf 模拟 +20lgR UAV , f 模拟 Represents the frequency of the equivalent signal of the analog downlink signal, R UAV Indicates the second distance from the UAV to the ground control station, L Air Indicates the propagation loss of the drone’s signal in the air;

[0045] Let the first transmission power be equivalent to the second transmission power, that is, let P 1-Ground =P 2-Ground , calculating the attenuation adjustment amount of the analog downlink signal;

[0046] The expression of the attenuation adjustment amount is:

[0047] ΔL=P UAV -P Satellite +20lgR Satellite -20lgR UAV +L Air_Satellite -L Air R UAV (4)

[0048] Among them, f 实际 =f 模拟 .

[0049] Furthermore, the step of making the frequency of the simulated downlink signal equivalent to the frequency of the actual downlink signal and calculating the coherent Doppler frequency shift adjustment amount of the simulated downlink signal when the ground measurement and control station performs coherent velocity measurement includes:

[0050] Calculating a first frequency of the actual downlink signal when the ground measurement and control station directly performs coherent velocity measurement on the satellite to be simulated;

[0051] The expression of the first frequency is:

[0052]

[0053] Among them, f R_Satellite Indicates the frequency of the actual uplink signal reaching the satellite to be simulated, f up Indicates the frequency of the transmission signal of the ground tracking and control station, v Satelliterepresents the radial velocity of the satellite to be simulated relative to the ground tracking station, c represents the speed of light, and f Down_Satellite represents the actual frequency of downlink signal transmission, ρ represents the coherent forwarding ratio, f R_Ground Indicates the first frequency at which the actual downlink signal arrives at the ground tracking and control station;

[0054] Calculating a second frequency of the simulated downlink signal when the ground measurement and control station performs coherent speed measurement on the UAV and adds a Doppler spectrum shift to the simulated downlink signal;

[0055] The expression of the second frequency is:

[0056]

[0057] Among them, f R_UAV represents the frequency of the simulated uplink signal reaching the drone, v UAV represents the radial velocity of the UAV relative to the ground tracking station, f Down_UAV Indicates the frequency of the simulated downlink signal transmission, f′ Down_UAV represents the frequency of the simulated downlink signal after adding the Doppler spectrum shift, Δf represents the coherent Doppler frequency shift adjustment, and f′ R_Ground Indicates the second frequency at which the analog downlink signal arrives at the ground tracking and control station;

[0058] Let the first frequency and the second frequency be equivalent, that is, let f R_Ground =f′ R_Ground , calculating the coherent Doppler frequency shift adjustment amount;

[0059] The expression of the coherent Doppler frequency shift adjustment amount is:

[0060]

[0061] Furthermore, the step of making the speed information of the UAV measured by the ground measurement and control station equivalent to the speed information of the simulated satellite measured by the ground measurement and control station, and calculating the incoherent Doppler frequency shift adjustment amount of the simulated downlink signal when the ground measurement and control station performs incoherent speed measurement includes:

[0062] respectively calculating a first uplink pseudo-Doppler measurement value and a first downlink pseudo-Doppler measurement value when the ground measurement and control station directly performs incoherent speed measurement on the UAV and the simulated downlink signal does not add the Doppler spectrum shift;

[0063] The expression of the first uplink pseudo-Doppler measurement value is:

[0064]

[0065] Among them, f上行1 represents the first uplink pseudo-Doppler measurement value, f up represents the frequency of the transmission signal of the ground tracking and control station, σ g (t1) represents the clock error of the drone at time t1, v UAV represents the radial velocity of the UAV relative to the ground control station, c represents the speed of light, σ s (t2) represents the clock error of the ground tracking and control station at time t2;

[0066] The expression of the first downlink pseudo-Doppler measurement value is:

[0067]

[0068] Among them, f 下行1 represents the first downlink pseudo-Doppler measurement value, f down represents the frequency of the received signal of the ground tracking and control station, σ g (t3) represents the UAV’s clock error at time t3;

[0069] Calculating respectively the second uplink pseudo-Doppler measurement value, the second downlink pseudo-Doppler measurement value, and the radial velocity measurement value of the UAV when the ground measurement and control station directly performs incoherent velocity measurement on the UAV and the Doppler spectrum shift is added to the simulated downlink signal;

[0070] The expression of the second uplink pseudo-Doppler measurement value is:

[0071]

[0072] Among them, f 上行2 Indicates the second uplink pseudo-Doppler measurement value;

[0073] The expression of the second downlink pseudo-Doppler measurement value is:

[0074]

[0075] Among them, f 下行2 represents the second downlink pseudo-Doppler measurement value, Δ′ f Indicates the incoherent Doppler frequency shift adjustment;

[0076] The expression of the measured value of the radial velocity of the UAV is:

[0077]

[0078] Among them, v m It represents the radial velocity of the UAV measured by the ground tracking and control station;

[0079] Calculating a first correlation between the first uplink pseudo-Doppler measurement value and the second uplink pseudo-Doppler measurement value, and calculating a second correlation between the first downlink pseudo-Doppler measurement value and the second downlink pseudo-Doppler measurement value;

[0080] The expression of the first mutual relationship is:

[0081] f 上行1 =f 上行2 (13)

[0082] The expression of the second mutual relationship is:

[0083]

[0084] Among them, Δ′ f Indicates the incoherent Doppler frequency shift adjustment;

[0085] Let the measured value of the UAV radial velocity be equivalent to the satellite radial velocity, that is, let v m =v Satellite , and calculating the incoherent Doppler frequency shift adjustment amount by using the first mutual relationship, the second mutual relationship, the first uplink pseudo-Doppler measurement value, and the first downlink pseudo-Doppler measurement value;

[0086] The expression of the incoherent Doppler frequency shift adjustment amount is:

[0087]

[0088] Among them, v Satellite It represents the radial velocity of the satellite to be simulated relative to the ground tracking and control station.

[0089] Beneficial effects:

[0090] This application provides a method for calculating channel parameters of a UAV simulating a satellite, which has at least the following beneficial effects:

[0091] (1) This application constructs a system model for the UAV to simulate satellite operation. When calculating the channel parameters such as the delay adjustment, attenuation adjustment, and Doppler frequency shift adjustment of the simulated downlink signal from the UAV to the ground tracking and control station, the positional relationship between the UAV, the satellite to be simulated, and the ground tracking and control station is taken into account. The measurement results of the UAV by the ground tracking and control station are equated with the measurement results of the satellite to be simulated, and the channel parameters are compensated, thereby making the simulation effect of the satellite channel more realistic.

[0092] (2) When calculating the channel parameters of the satellite to be simulated by the drone, the present application utilizes the real-time positioning information of the drone to calculate its position information and speed information, thereby effectively reducing the calculation error of the position information and speed information caused by the flight deviation of the drone. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0094] Figure 1 A schematic diagram showing the steps of a method for calculating channel parameters of a UAV simulating a satellite in an exemplary embodiment of the present application;

[0095] Figure 2 A schematic diagram showing a system model of a UAV simulating satellite operation in an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0096] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0097] In addition, the accompanying drawings are merely schematic illustrations of the present application and are not necessarily drawn to scale. Identical reference numerals in the figures denote identical or similar parts, and thus repetitive descriptions thereof will be omitted. Some of the blocks shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically separate entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0098] To this end, this example embodiment provides a method for calculating channel parameters of a UAV simulating a satellite, such as Figure 1 and Figure 2 As shown, the method may include the following steps:

[0099] Step S101: Constructing a system model for the UAV to simulate satellite operation, the system model includes a ground tracking and control station, a UAV, and a satellite to be simulated; the UAV is always in the tracking and control link between the ground tracking and control station and the satellite to be simulated, and the tracking and control link includes an uplink and a downlink;

[0100] Step S102: Determine the location information of the ground tracking and control station, obtain the satellite trajectory information of the satellite to be simulated, and simultaneously obtain the flight trajectory information of the UAV;

[0101] Step S103: using the position information, satellite trajectory information, and flight trajectory information of the ground tracking and control station, respectively calculate the satellite radial velocity of the simulated satellite relative to the ground tracking and control station, and the UAV radial velocity of the UAV relative to the ground tracking and control station;

[0102] Step S104: Calculate the channel parameters of the system model using the satellite trajectory information, flight trajectory information, satellite radial velocity, and UAV radial velocity;

[0103] Among them, the channel parameters include the delay adjustment, attenuation adjustment and Doppler frequency shift adjustment of the analog downlink signal from the UAV to the ground measurement and control station.

[0104] The present application provides a method for calculating channel parameters of a UAV simulating a satellite, which has at least the following beneficial effects:

[0105] (1) This application constructs a system model for the UAV to simulate satellite operation. When calculating the channel parameters such as the delay adjustment, attenuation adjustment, and Doppler frequency shift adjustment of the simulated downlink signal from the UAV to the ground tracking and control station, the positional relationship between the UAV, the satellite to be simulated, and the ground tracking and control station is taken into account. The measurement results of the UAV by the ground tracking and control station are equated with the measurement results of the satellite to be simulated, and the channel parameters are compensated, thereby making the simulation effect of the satellite channel more realistic.

[0106] (2) When calculating the channel parameters of the satellite to be simulated by the drone, the present application utilizes the real-time positioning information of the drone to calculate its position information and speed information, thereby effectively reducing the calculation error of the position information and speed information caused by the flight deviation of the drone.

[0107] The following is a more detailed description of the channel parameter calculation method for a UAV simulating a satellite proposed in this example embodiment.

[0108] In step S101 of this embodiment, a system model for a UAV to simulate satellite operation is constructed.

[0109] Furthermore, the system model includes a ground tracking and control station, a UAV and a satellite to be simulated; wherein the UAV is always located on the tracking and control link between the ground tracking and control station and the satellite to be simulated, and the tracking and control link includes an uplink and a downlink.

[0110] Furthermore, the UAV is equipped with a measurement and control transponder and a channel simulator; the uplink includes a simulated uplink signal from the ground measurement and control station to the UAV, and an actual uplink signal from the ground measurement and control station to the satellite to be simulated; the downlink includes a simulated downlink signal from the UAV to the ground measurement and control station, and an actual downlink signal from the satellite to be simulated to the ground measurement and control station.

[0111] In step S102 of this embodiment, the position information of the ground tracking and control station is determined, the satellite trajectory information of the satellite to be simulated is obtained, and the flight trajectory information of the UAV is obtained at the same time. Step S102 of this embodiment may include the following sub-steps:

[0112] Sub-step S1021: Calculate satellite trajectory information according to the orbital elements of the satellite to be simulated.

[0113] Furthermore, the satellite trajectory information includes position information and speed information of the satellite to be simulated.

[0114] Sub-step S1022: Acquire flight trajectory information based on the real-time positioning information of the UAV during flight, and smooth the flight trajectory information, thereby improving the accuracy and reliability of the flight trajectory information, making the flight trajectory information smoother and easier to analyze.

[0115] Furthermore, the flight trajectory information includes the position information and speed information of the UAV.

[0116] Sub-step S1023: Determine the location information of the ground measurement and control station.

[0117] In step S103 of this embodiment, the position information of the ground tracking and control station, the satellite trajectory information, and the flight trajectory information are used to calculate the satellite radial velocity of the simulated satellite relative to the ground tracking and control station, and the UAV radial velocity of the UAV relative to the ground tracking and control station. In this embodiment, step S103 may include the following sub-steps:

[0118] Sub-step S1031: converting the satellite trajectory information, flight trajectory information and the position information of the ground tracking and control station into the same coordinate system.

[0119] Sub-step S1032: Calculate the satellite radial velocity based on the satellite trajectory information and the position information of the ground tracking and control station.

[0120] Sub-step S1033: Calculate the radial velocity of the UAV based on the flight trajectory information and the position information of the ground measurement and control station.

[0121] In step S104 of this embodiment, the channel parameters of the system model are calculated using the satellite trajectory information, flight trajectory information, satellite radial velocity, and UAV radial velocity. Step S104 of this embodiment may include the following sub-steps:

[0122] Sub-step S1041: Figure 2 It can be seen that the delay adjustment of the simulated downlink signal is calculated based on the difference between the distance between the simulated satellite and the ground tracking and control station and the distance between the drone and the ground tracking and control station. The specific process is as follows:

[0123] First, a first distance between the satellite to be simulated and the ground measurement and control station is calculated based on the position information of the satellite to be simulated and the position information of the ground measurement and control station in the same coordinate system.

[0124] Next, a second distance from the UAV to the ground measurement and control station is calculated based on the position information of the UAV in the coordinate system and the position information of the ground measurement and control station.

[0125] Then, a distance difference between the first distance and the second distance is calculated.

[0126] Finally, the ranging result of the UAV by the ground tracking and control station is made equivalent to the ranging result of the simulated satellite by the ground tracking and control station, and the delay adjustment of the simulated downlink signal is calculated using the distance difference.

[0127] Furthermore, the delay adjustment value of the simulated downlink signal is expressed as:

[0128]

[0129] Among them, Δt represents the delay adjustment of the analog downlink signal, R Satellite Indicates the first distance between the simulated satellite and the ground tracking station, R UAV represents the second distance from the UAV to the ground tracking and control station, and c represents the speed of light.

[0130] Sub-step S1042: Calculate the attenuation adjustment of the simulated downlink signal using the transmission power of the actual downlink signal and the simulated downlink signal. The specific process is as follows:

[0131] First, the first transmission power of the actual downlink signal is calculated.

[0132] According to the free space propagation theory, the propagation loss of a known signal in free space can be expressed as:

[0133] L Los =32.44+20lgf+20lgd

[0134] Among them, L Los It represents the propagation loss of a known signal in free space in km, f represents the frequency of the known signal in MHz, and d represents the distance between the transmitter and the receiver.

[0135] Furthermore, the expression of the first transmission power is:

[0136] P 1-Ground =P Satellite -L Los_Satellite -L Air_Satellite (2)

[0137] Among them, P 1-Ground Indicates the first transmission power of the actual downlink signal, PSatellite Indicates the equivalent radiated power of the actual downlink signal, L Los_Satellite Indicates the propagation loss of the satellite signal to be simulated in free space, L Los_Satellite =32.44+20lgf 实际 +20lgR Satellite , f 实际 Indicates the frequency of the equivalent signal of the actual downlink signal, R Satellite Indicates the first distance from the simulated satellite to the ground tracking station, L Air_Satellite It represents the atmospheric loss of the satellite signal to be simulated when it passes through the atmosphere.

[0138] Here, at frequency f 实际 When the atmospheric loss L of the signal from the satellite to be simulated passing through the atmosphere is determined, Air_Satellite It is related to the real-time elevation angle of the simulated satellite relative to the ground tracking station and can be obtained by table lookup. Taking into account the propagation loss in free space and the atmospheric absorption loss, we can get formula (2).

[0139] Next, the second transmission power of the simulated downlink signal is calculated.

[0140] Furthermore, the expression of the second transmission power is:

[0141] P 2-Ground =P UAV -ΔL-L Los_UAV -L Air R UAV (3)

[0142] Among them, P 2-Ground represents the second transmission power of the simulated downlink signal, P UAV It represents the equivalent radiated power of the simulated downlink signal, ΔL represents the attenuation adjustment of the simulated downlink signal, L Los_UAV represents the propagation loss of the UAV signal in free space, L Los_UAV =32.44+20lgf 模拟 +20lgR UAV , f 模拟 Represents the frequency of the equivalent signal of the analog downlink signal, R UAV Indicates the second distance from the UAV to the ground control station, L Air Indicates the propagation loss of the drone’s signal in the air.

[0143] Finally, let the first transmission power be equivalent to the second transmission power, that is, let P 1-Ground =P 2-Ground , calculate the attenuation adjustment of the analog downlink signal.

[0144] Furthermore, the expression of the attenuation adjustment amount is:

[0145] ΔL=P UAV -P Satellite +20lgR Satellite -20lgR UAV +L Air_Satellite -L Air R UAV (4)

[0146] Among them, f 实际 =f 模拟 .

[0147] Sub-step S1043: The frequency of the simulated downlink signal is made equivalent to the frequency of the actual downlink signal, and the coherent Doppler frequency shift adjustment of the simulated downlink signal is calculated when the ground tracking and control station performs coherent velocity measurement. The specific process is as follows:

[0148] First, the first frequency of the actual downlink signal when the ground tracking and control station directly performs coherent velocity measurement on the simulated satellite is calculated.

[0149] Furthermore, the expression of the first frequency is:

[0150]

[0151] Among them, f R_Satellite Indicates the frequency of the actual uplink signal reaching the satellite to be simulated, f up Indicates the frequency of the transmission signal of the ground tracking and control station, v Satellite represents the radial velocity of the satellite to be simulated relative to the ground tracking station, c represents the speed of light, and f Down_Satellite represents the actual frequency of downlink signal transmission, ρ represents the coherent forwarding ratio, f R_Ground Indicates the first frequency at which the actual downlink signal arrives at the ground tracking and control station.

[0152] Next, the second frequency of the simulated downlink signal is calculated when the ground measurement and control station performs coherent speed measurement on the UAV and adds a Doppler spectrum shift to the simulated downlink signal.

[0153] Furthermore, the expression of the second frequency is:

[0154]

[0155] Among them, f R_UAV Indicates the frequency at which the simulated uplink signal reaches the drone, v UAV represents the radial velocity of the UAV relative to the ground tracking station, f Down_UAV Indicates the frequency of the simulated downlink signal transmission, f′ Down_UAV represents the simulated downlink signal after adding Doppler spectrum shift, Δf represents the coherent Doppler frequency shift adjustment, and f′ R_GroundIndicates the second frequency at which the analog downlink signal arrives at the ground tracking and control station.

[0156] Finally, let the first frequency and the second frequency be equivalent, that is, let f R_Ground =f′ R_Ground , calculate the coherent Doppler frequency shift adjustment.

[0157] Furthermore, the expression of the coherent Doppler frequency shift adjustment amount is:

[0158]

[0159] Sub-step S1044: The speed information of the UAV measured by the ground tracking and control station is made equivalent to the speed information of the simulated satellite measured by the ground tracking and control station, and the incoherent Doppler frequency shift adjustment amount of the simulated downlink signal is calculated when the ground tracking and control station performs incoherent speed measurement. The specific process is as follows:

[0160] Firstly, the first uplink pseudo-Doppler measurement value and the first downlink pseudo-Doppler measurement value are calculated respectively when the ground tracking and control station directly performs incoherent speed measurement on the UAV and simulates the downlink signal without adding Doppler spectrum shift.

[0161] Furthermore, the expression of the first uplink pseudo-Doppler measurement value is:

[0162]

[0163] Among them, f 上行1 represents the first uplink pseudo-Doppler measurement value, f up represents the frequency of the transmission signal of the ground tracking and control station, σ g (t1) represents the clock error of the drone at time t1, v UAV represents the radial velocity of the UAV relative to the ground control station, c represents the speed of light, σ s (t2) represents the clock error of the ground tracking and control station at time t2.

[0164] Furthermore, the expression of the first downlink pseudo-Doppler measurement value is:

[0165]

[0166] Among them, f 下行1 represents the first downlink pseudo-Doppler measurement value, f down represents the frequency of the received signal of the ground tracking and control station, σ g (t3) represents the clock error of the drone at time t3.

[0167] Then, the second uplink pseudo-Doppler measurement value, the second downlink pseudo-Doppler measurement value, and the radial velocity measurement value of the UAV are calculated respectively when the ground tracking and control station directly performs incoherent velocity measurement on the UAV and simulates the downlink signal adding Doppler spectrum shift.

[0168] Furthermore, the expression of the second uplink pseudo-Doppler measurement value is:

[0169]

[0170] Among them, f 上行2 Indicates the second uplink pseudo-Doppler measurement value;

[0171] The expression of the second downlink pseudo-Doppler measurement value is:

[0172]

[0173] Among them, f 下行2 represents the second downlink pseudo-Doppler measurement value, Δ′ f Indicates the incoherent Doppler frequency shift adjustment;

[0174] The expression for the measured value of the UAV radial velocity is:

[0175]

[0176] Among them, v m It represents the radial velocity of the UAV measured by the ground tracking and control station.

[0177] Then, a first correlation between the first uplink pseudo-Doppler measurement value and the second uplink pseudo-Doppler measurement value is calculated, and a second correlation between the first downlink pseudo-Doppler measurement value and the second downlink pseudo-Doppler measurement value is calculated.

[0178] Furthermore, the expression of the first mutual relationship is:

[0179] f 上行1 =f 上行2 (13)

[0180] The expression of the second mutual relationship is:

[0181]

[0182] Among them, Δ′ f Indicates the incoherent Doppler shift adjustment amount.

[0183] Finally, let the measured value of the UAV radial velocity be equivalent to the satellite radial velocity, that is, let v m =v Satellite, and calculating the incoherent Doppler frequency shift adjustment amount using the first correlation, the second correlation, the first uplink pseudo-Doppler measurement value, and the first downlink pseudo-Doppler measurement value.

[0184] Furthermore, v m =v Satellite , formula (13) and formula (14) into formula (12), we can get:

[0185]

[0186] Substituting equations (8) and (9) into the above equations, we can obtain the expression of the incoherent Doppler frequency shift adjustment:

[0187]

[0188] Among them, v Satellite It represents the radial velocity of the satellite to be simulated relative to the ground tracking and control station.

[0189] Here, the Doppler frequency shift adjustment amount includes a coherent Doppler frequency shift adjustment amount and an incoherent Doppler frequency shift adjustment amount.

[0190] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of this application, the meaning of "plurality" is two or more, unless otherwise clearly specified.

[0191] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0192] The above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with this technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the scope of protection of the present application.

[0193] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of this application and include common knowledge or customary techniques in the art that are not disclosed herein.

Claims

1. A method for calculating channel parameters of a UAV simulating a satellite, characterized in that: The method comprises the following steps: Constructing a system model for the UAV to simulate satellite operation, the system model includes a ground tracking and control station, a UAV, and a satellite to be simulated; the UAV is always located on a tracking and control link between the ground tracking and control station and the satellite to be simulated, the tracking and control link including an uplink and a downlink; Determine the location information of the ground measurement and control station, obtain the satellite trajectory information of the satellite to be simulated, and simultaneously obtain the flight trajectory information of the UAV; Calculate the satellite radial velocity of the simulated satellite relative to the ground measurement and control station and the UAV radial velocity of the UAV relative to the ground measurement and control station using the position information of the ground measurement and control station, the satellite trajectory information, and the flight trajectory information; Calculating channel parameters of the system model using the satellite trajectory information, the flight trajectory information, the satellite radial velocity, and the UAV radial velocity; The channel parameters include a delay adjustment amount, an attenuation adjustment amount, and a Doppler frequency shift adjustment amount of the analog downlink signal from the UAV to the ground measurement and control station.

2. The method for calculating channel parameters of a UAV simulating a satellite according to claim 1, characterized in that: The UAV is equipped with a measurement and control transponder and a channel simulator; the uplink includes a simulated uplink signal from the ground measurement and control station to the UAV, and an actual uplink signal from the ground measurement and control station to the satellite to be simulated; the downlink includes the simulated downlink signal from the UAV to the ground measurement and control station, and an actual downlink signal from the satellite to be simulated to the ground measurement and control station.

3. The method for calculating channel parameters of a UAV simulating a satellite according to claim 2, wherein: The steps of determining the position information of the ground measurement and control station, obtaining the satellite trajectory information of the satellite to be simulated, and simultaneously obtaining the flight trajectory information of the UAV include: Calculating the satellite trajectory information according to the orbital elements of the satellite to be simulated; Acquiring the flight trajectory information according to the real-time positioning information of the UAV during flight, and performing smoothing processing on the flight trajectory information; Determine the location information of the ground measurement and control station.

4. The method for calculating channel parameters of a UAV simulating a satellite according to claim 3, wherein: The satellite trajectory information includes the position information and speed information of the satellite to be simulated; the flight trajectory information includes the position information and speed information of the UAV.

5. The method for calculating channel parameters of a UAV simulating a satellite according to claim 4, characterized in that: The step of respectively calculating the satellite radial velocity of the satellite to be simulated relative to the ground measurement and control station and the UAV radial velocity of the UAV relative to the ground measurement and control station by using the position information of the ground measurement and control station, the satellite trajectory information, and the flight trajectory information comprises: Converting the satellite trajectory information, the flight trajectory information, and the position information of the ground measurement and control station into the same coordinate system; Calculating the satellite radial velocity based on the satellite trajectory information and the position information of the ground measurement and control station; The radial velocity of the UAV is calculated based on the flight trajectory information and the position information of the ground measurement and control station.

6. The method for calculating channel parameters of a UAV simulating a satellite according to claim 5, characterized in that: The step of calculating the channel parameters of the system model using the satellite trajectory information, the flight trajectory information, the satellite radial velocity, and the UAV radial velocity includes: Calculating the delay adjustment amount of the simulated downlink signal according to the difference between the distance between the simulated satellite and the ground measurement and control station and the distance between the UAV and the ground measurement and control station; Calculating the attenuation adjustment amount of the simulated downlink signal by using the transmission power of the actual downlink signal and the simulated downlink signal; Setting the frequency of the simulated downlink signal to be equivalent to the frequency of the actual downlink signal, and calculating the coherent Doppler frequency shift adjustment amount of the simulated downlink signal when the ground measurement and control station performs coherent velocity measurement; Making the speed information of the UAV measured by the ground measurement and control station equivalent to the speed information of the simulated satellite measured by the ground measurement and control station, and calculating the incoherent Doppler frequency shift adjustment amount of the simulated downlink signal when the ground measurement and control station performs incoherent speed measurement; The Doppler frequency shift adjustment amount includes the coherent Doppler frequency shift adjustment amount and the incoherent Doppler frequency shift adjustment amount.

7. The method for calculating channel parameters of a UAV simulating a satellite according to claim 6, characterized in that: The step of calculating the delay adjustment amount of the simulated downlink signal according to the difference between the distance between the simulated satellite and the ground measurement and control station and the distance between the UAV and the ground measurement and control station includes: Calculating a first distance from the satellite to be simulated to the ground measurement and control station according to the position information of the satellite to be simulated in the coordinate system and the position information of the ground measurement and control station; Calculating a second distance from the UAV to the ground measurement and control station based on the position information of the UAV in the coordinate system and the position information of the ground measurement and control station; Calculating a distance difference between the first distance and the second distance; Making the ranging result of the ground measurement and control station for the UAV equivalent to the ranging result of the ground measurement and control station for the simulated satellite, and calculating the delay adjustment amount of the simulated downlink signal using the distance difference; The expression of the delay adjustment amount of the simulated downlink signal is: Among them, Δt represents the delay adjustment of the analog downlink signal, R Satellite Indicates the first distance from the simulated satellite to the ground tracking station, R UAV represents the second distance from the UAV to the ground tracking and control station, and c represents the speed of light.

8. The method for calculating channel parameters of a UAV simulating a satellite according to claim 6, characterized in that: The step of calculating the attenuation adjustment amount of the simulated downlink signal by using the transmission power of the actual downlink signal and the simulated downlink signal includes: Calculating a first transmission power of the actual downlink signal; The expression of the first transmission power is: P 1-Ground =P Satellite -L Los_Satellite -L Air_Satellite (2) Among them, P 1-Ground Indicates the first transmission power of the actual downlink signal, P Satellite Indicates the equivalent radiated power of the actual downlink signal, L Los_Satellite Indicates the propagation loss of the satellite signal to be simulated in free space, L Los_Satellite =32.44+20lgf 实际 +20lgR Satellite , f 实际 Indicates the frequency of the equivalent signal of the actual downlink signal, R Satellite Indicates the first distance from the simulated satellite to the ground tracking station, L Air_Satellite represents the atmospheric loss of the signal from the satellite to be simulated as it passes through the atmosphere; Calculating a second transmission power of the simulated downlink signal; The expression of the second transmission power is: P 2-Ground =P UAV -ΔL-L Los_UAV -L Air R UAV (3) Among them, P 2-Ground represents the second transmission power of the simulated downlink signal, P UAV It represents the equivalent radiated power of the simulated downlink signal, ΔL represents the attenuation adjustment of the simulated downlink signal, L Los_UAV represents the propagation loss of the UAV signal in free space, L Los_UAV =32.44+20lgf 模拟 +20lgR UAV , f 模拟 Represents the frequency of the equivalent signal of the analog downlink signal, R UAV Indicates the second distance from the UAV to the ground control station, L Air Indicates the propagation loss of the drone’s signal in the air; Let the first transmission power be equivalent to the second transmission power, that is, let P 1-Ground =P 2-Ground , calculating the attenuation adjustment amount of the analog downlink signal; The expression of the attenuation adjustment amount is: ΔL=P UAV -P Satellite +20lgR Satellite -20lgR UAV +L Air_Satellite -L Air R UAV (4) Among them, f 实际 =f 模拟 .

9. The method for calculating channel parameters of a UAV simulating a satellite according to claim 6, characterized in that: The step of making the frequency of the simulated downlink signal equivalent to the frequency of the actual downlink signal and calculating the coherent Doppler frequency shift adjustment amount of the simulated downlink signal when the ground measurement and control station performs coherent velocity measurement includes: Calculating a first frequency of the actual downlink signal when the ground measurement and control station directly performs coherent velocity measurement on the satellite to be simulated; The expression of the first frequency is: Among them, f R_Satellite Indicates the frequency of the actual uplink signal reaching the satellite to be simulated, f up Indicates the frequency of the transmission signal of the ground tracking and control station, v Satellite represents the radial velocity of the satellite to be simulated relative to the ground tracking station, c represents the speed of light, and f Down_Satellite represents the actual frequency of downlink signal transmission, ρ represents the coherent forwarding ratio, f R_Ground Indicates the first frequency at which the actual downlink signal arrives at the ground tracking and control station; Calculating a second frequency of the simulated downlink signal when the ground measurement and control station performs coherent speed measurement on the UAV and adds a Doppler spectrum shift to the simulated downlink signal; The expression of the second frequency is: Among them, f R_UAV represents the frequency of the simulated uplink signal reaching the drone, v UAV represents the radial velocity of the UAV relative to the ground tracking station, f Down_UAV Indicates the frequency of the simulated downlink signal transmission, f′ Down_UAV represents the frequency of the simulated downlink signal after adding the Doppler spectrum shift, Δf represents the coherent Doppler frequency shift adjustment, and f′ R_Ground Indicates the second frequency at which the analog downlink signal arrives at the ground tracking and control station; Let the first frequency and the second frequency be equivalent, that is, let f R_Ground =f′ R_Ground , calculating the coherent Doppler frequency shift adjustment amount; The expression of the coherent Doppler frequency shift adjustment amount is:

10. The method for calculating channel parameters of a UAV simulating a satellite according to claim 6, characterized in that: The step of making the speed information of the UAV measured by the ground measurement and control station equivalent to the speed information of the simulated satellite measured by the ground measurement and control station, and calculating the incoherent Doppler frequency shift adjustment amount of the simulated downlink signal when the ground measurement and control station performs incoherent speed measurement comprises: respectively calculating a first uplink pseudo-Doppler measurement value and a first downlink pseudo-Doppler measurement value when the ground measurement and control station directly performs incoherent speed measurement on the UAV and the simulated downlink signal does not add the Doppler spectrum shift; The expression of the first uplink pseudo-Doppler measurement value is: Among them, f 上行1 represents the first uplink pseudo-Doppler measurement value, f up represents the frequency of the transmission signal of the ground tracking and control station, σ g (t1) represents the clock error of the drone at time t1, v UAV represents the radial velocity of the UAV relative to the ground control station, c represents the speed of light, σ s (t2) represents the clock error of the ground tracking and control station at time t2; The expression of the first downlink pseudo-Doppler measurement value is: Among them, f 下行1 represents the first downlink pseudo-Doppler measurement value, f down represents the frequency of the received signal of the ground tracking and control station, σ g (t3) represents the UAV’s clock error at time t3; Calculating respectively the second uplink pseudo-Doppler measurement value, the second downlink pseudo-Doppler measurement value, and the radial velocity measurement value of the UAV when the ground measurement and control station directly performs incoherent velocity measurement on the UAV and the Doppler spectrum shift is added to the simulated downlink signal; The expression of the second uplink pseudo-Doppler measurement value is: Among them, f 上行2 Indicates the second uplink pseudo-Doppler measurement value; The expression of the second downlink pseudo-Doppler measurement value is: Among them, f 下行2 represents the second downlink pseudo-Doppler measurement value, Δ′ f Indicates the incoherent Doppler frequency shift adjustment; The expression of the measured value of the radial velocity of the UAV is: Among them, v m It represents the radial velocity of the UAV measured by the ground tracking and control station; Calculating a first correlation between the first uplink pseudo-Doppler measurement value and the second uplink pseudo-Doppler measurement value, and calculating a second correlation between the first downlink pseudo-Doppler measurement value and the second downlink pseudo-Doppler measurement value; The expression of the first mutual relationship is: f 上行1 =f 上行2 (13) The expression of the second mutual relationship is: Among them, Δ′ f Indicates the incoherent Doppler frequency shift adjustment; Let the measured value of the UAV radial velocity be equivalent to the satellite radial velocity, that is, let v m =v Satellite , and calculating the incoherent Doppler frequency shift adjustment amount by using the first mutual relationship, the second mutual relationship, the first uplink pseudo-Doppler measurement value, and the first downlink pseudo-Doppler measurement value; The expression of the incoherent Doppler frequency shift adjustment amount is: Among them, v Satellite It represents the radial velocity of the satellite to be simulated relative to the ground tracking and control station.

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