阅读说明：本技术 一种基于无人机数据链的应急导航方法 (Emergency navigation method based on unmanned aerial vehicle data link ) 是由 耿炎 许瑞生 崔项飞 张俊凯 于 2020-11-20 设计创作，主要内容包括：本发明公开了一种基于无人机数据链的应急导航方法,属于无人机测控技术领域。本发明利用上、下行双向链路测量无人机到地面测控站的距离；地面测控站采用定向天线接收无人机下行信号,通过单脉冲自跟踪功能可测量无人机的方位角；通过对无人机实时测距、测角,推算出无人机的实时位置坐标,实现应急导航。本发明可在卫星导航信号受到干扰时为无人机提供应急导航信息。(The invention discloses an emergency navigation method based on an unmanned aerial vehicle data chain, and belongs to the technical field of unmanned aerial vehicle measurement and control. The invention uses the uplink and downlink bidirectional links to measure the distance from the unmanned aerial vehicle to the ground measurement and control station; the ground measurement and control station adopts a directional antenna to receive downlink signals of the unmanned aerial vehicle, and can measure the azimuth angle of the unmanned aerial vehicle through a monopulse self-tracking function; through to unmanned aerial vehicle real-time ranging, angle measurement, calculate unmanned aerial vehicle's real-time position coordinate, realize emergent navigation. The invention can provide emergency navigation information for the unmanned aerial vehicle when the satellite navigation signal is interfered.)

1. An emergency navigation method based on an unmanned aerial vehicle data chain is characterized by comprising the following steps:

(1) ranging the unmanned aerial vehicle by utilizing an uplink bidirectional link and a downlink bidirectional link of the unmanned aerial vehicle data link;

(2) measuring the angle of the unmanned aerial vehicle by utilizing the monopulse self-tracking function of the directional antenna of the ground measurement and control station of the unmanned aerial vehicle;

(3) and calculating the longitude and latitude coordinates of the unmanned aerial vehicle according to the known coordinates of the ground measurement and control station and the distance and azimuth information obtained by observing the unmanned aerial vehicle, so as to realize the navigation of the unmanned aerial vehicle.

2. The emergency navigation method based on the data chain of the unmanned aerial vehicle as claimed in claim 1, wherein the specific manner of step (1) is as follows:

(101) taking a remote control telemetering data frame head in an unmanned aerial vehicle data chain as a ranging pulse, and starting a first timer when a ground measurement and control station sends an uplink remote control data frame head;

(102) when the airborne measurement and control terminal receives the head of the uplink remote control data frame, a second timer is started;

(103) when the airborne measurement and control terminal sends a downlink telemetering data frame header, stopping the second timer, and simultaneously sending the timing time T2 of the second timer to the ground measurement and control station through downlink telemetering;

(104) when the ground measurement and control station receives the head of the downlink telemetry data frame, stopping the first timer and simultaneously outputting the timing time T1 of the first timer;

(105) taking the value of T1-T2 as the sum of the bidirectional transmission time of the telemetering radio signal and the processing time delay tau of the equipment; zero calibration is carried out on the distance measurement value, the equipment processing time delay tau is removed, and the distance r from the unmanned aerial vehicle to the ground measurement and control station is obtained:

r＝(T1-T2-τ)*C/2

wherein C is the speed of light;

(106) and acquiring a plurality of ranging values, analyzing and calculating according to the frame period of the remote control and telemetry data frame and the action distance of the link, eliminating fuzzy values, and smoothing the residual ranging values to obtain a ranging result.

3. The emergency navigation method based on the data chain of the unmanned aerial vehicle as claimed in claim 1, wherein the specific manner of step (2) is as follows:

(201) performing initial calibration on the ground measurement and control station to determine the latitude B of the ground measurement and control station₀Longitude L, longitude₀And height H₀(ii) a Obtaining initial azimuth angle A of antenna zero position₀Performing distance zero calibration, and reading the height H of the target airplane from remote measurement;

(202) a directional antenna of the ground measurement and control station receives downlink radio frequency signals of the unmanned aerial vehicle, wherein the amplitude-comparing monopulse antenna receives signals through two offset feed horns, and the phase-comparing monopulse antenna receives signals through two sub-arrays arranged at intervals; the two paths of signals generate a sum path signal and a difference path signal through a high-frequency sum and difference device;

(203) performing 0-pi modulation on the difference signal by using a low-frequency square wave of 1-10 kHz;

(204) synthesizing the modulated difference path signal and the modulated sum path signal by a coupler, wherein the coupling degree is selected to be-6 to-14 dB, and forming a single-channel carrier signal;

(205) the synthesized single-channel signal is subjected to low-noise amplification and frequency conversion to become an intermediate-frequency signal with stronger amplitude, and then the intermediate-frequency signal is sent to a tracking receiver;

(206) the tracking receiver carries out coherent amplitude detection on the signal and takes out a low-frequency modulation signal; then, carrying out synchronous detection by using a reference square wave signal to separate an azimuth angle error voltage signal;

(207) sending the azimuth angle error signal to an antenna servo to carry out closed-loop control, and driving a directional antenna to track and align a target; servo system reports azimuth angle A when directional antenna tracks alignment target₁；

(208) The azimuth reported by an initial azimuth superposition servo system of the antenna zero is used as a geographical azimuth A of the airplane:

A＝A₀+A₁。

4. the emergency navigation method based on the data chain of the unmanned aerial vehicle as claimed in claim 1, wherein the specific manner of step (3) is as follows:

(301) calculating coordinates (x, y and z) of the target unmanned aerial vehicle under a station center coordinate system of the ground measurement and control station:

in the formula: q is the elevation angle of the target unmanned aerial vehicle, the initial value is 0, r is the distance from the target unmanned aerial vehicle to the ground measurement and control station, and A is the azimuth angle of the target unmanned aerial vehicle;

(302) calculating coordinates (X, Y, Z) of the target unmanned aerial vehicle under a space rectangular coordinate system:

in the formula:is the radius of curvature of the prime;is the square of the first eccentricity, a is the ellipsoid major semi-axis, and b is the ellipsoid minor semi-axis; B. l, H the initial value is latitude B of ground measurement and control station₀Longitude L, longitude₀And height H₀；

(303) Eyes of calculationGeodetic coordinates of the drone (B)_T、L_T、H_T)：

(304) Judgment of H-H_TIf the value is less than the threshold value, go to step (306) if yes, otherwise go to step (305);

(305) calculating the correction d of the elevation angle_q＝(H-H_T) R, and let q be q + d_q，B＝B_T，L＝L_T，H＝H_TRepeating the steps (301) to (304) to perform iterative calculation;

(306) outputting geodetic coordinates (B) of the target drone under WGS84_T、L_T) And emergency navigation data are provided for the unmanned aerial vehicle.

Technical Field

The invention relates to the technical field of unmanned aerial vehicle measurement and control, in particular to an emergency navigation method based on an unmanned aerial vehicle data chain.

Background

In modern information war, unmanned aerial vehicle can satisfy zero casualties and the high requirement of reuse rate, can carry out the task of high risk to provide investigation information for the military, assist and acquire the electromagnetism right, have the position of playing a vital role in modern battlefield. The basic task of the navigation system is to control the unmanned aerial vehicle to fly according to a predetermined task route.

Navigation systems typically employ a variety of navigation approaches, primarily satellite navigation. The satellite navigation has the characteristics of omnibearing, all-weather, all-time and high precision, but is easy to be interfered. Because the signal transmitting power of the navigation satellite is limited to a certain extent, the distance from the satellite to the earth surface is about more than twenty thousand meters, and the strength of the signal is very small when the navigation signal reaches the earth, the navigation receiver is very easy to be interfered by the outside world, so that the unmanned aerial vehicle gets lost.

Disclosure of Invention

In view of the above, the invention provides an emergency navigation method based on an unmanned aerial vehicle data chain, and aims to provide navigation information for an unmanned aerial vehicle under the condition that a satellite navigation signal is interfered.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

an emergency navigation method based on an unmanned aerial vehicle data chain comprises the following steps:

(1) ranging the unmanned aerial vehicle by utilizing an uplink bidirectional link and a downlink bidirectional link of the unmanned aerial vehicle data link;

(2) measuring the angle of the unmanned aerial vehicle by utilizing the monopulse self-tracking function of the directional antenna of the ground measurement and control station of the unmanned aerial vehicle;

(3) and calculating the longitude and latitude coordinates of the unmanned aerial vehicle according to the known coordinates of the ground measurement and control station and the distance and azimuth information obtained by observing the unmanned aerial vehicle, so as to realize the navigation of the unmanned aerial vehicle.

Further, the specific mode of the step (1) is as follows:

(101) taking a remote control telemetering data frame head in an unmanned aerial vehicle data chain as a ranging pulse, and starting a first timer when a ground measurement and control station sends an uplink remote control data frame head;

(102) when the airborne measurement and control terminal receives the head of the uplink remote control data frame, a second timer is started;

(103) when the airborne measurement and control terminal sends a downlink telemetering data frame header, stopping the second timer, and simultaneously sending the timing time T2 of the second timer to the ground measurement and control station through downlink telemetering;

(104) when the ground measurement and control station receives the head of the downlink telemetry data frame, stopping the first timer and simultaneously outputting the timing time T1 of the first timer;

(105) taking the value of T1-T2 as the sum of the bidirectional transmission time of the telemetering radio signal and the processing time delay tau of the equipment; zero calibration is carried out on the distance measurement value, the equipment processing time delay tau is removed, and the distance r from the unmanned aerial vehicle to the ground measurement and control station is obtained:

r＝(T1-T2-τ)*C/2

wherein C is the speed of light;

(106) and acquiring a plurality of ranging values, analyzing and calculating according to the frame period of the remote control and telemetry data frame and the action distance of the link, eliminating fuzzy values, and smoothing the residual ranging values to obtain a ranging result.

Further, the specific mode of the step (2) is as follows:

(201) performing initial calibration on the ground measurement and control station to determine the latitude B of the ground station₀Longitude L, longitude₀And height H₀(ii) a Obtaining initial azimuth angle A of antenna zero position₀Performing distance zero calibration, and reading the height H of the target airplane from remote measurement;

(202) a directional antenna of the ground measurement and control station receives downlink radio frequency signals of the unmanned aerial vehicle, wherein the amplitude-comparing monopulse antenna receives signals through two offset feed horns, and the phase-comparing monopulse antenna receives signals through two sub-arrays arranged at intervals; the two paths of signals generate a sum path signal and a difference path signal through a high-frequency sum and difference device;

(203) performing 0-pi modulation on the difference signal by using a low-frequency square wave of 1-10 kHz;

(204) synthesizing the modulated difference path signal and the modulated sum path signal by a coupler, wherein the coupling degree is selected to be-6 to-14 dB, and forming a single-channel carrier signal;

(205) the synthesized single-channel signal is subjected to low-noise amplification and frequency conversion to become an intermediate-frequency signal with stronger amplitude, and then the intermediate-frequency signal is sent to a tracking receiver;

(206) the tracking receiver carries out coherent amplitude detection on the signal and takes out a low-frequency modulation signal; then, carrying out synchronous detection by using a reference square wave signal to separate an azimuth angle error voltage signal;

(207) sending the azimuth angle error signal to an antenna servo to carry out closed-loop control, and driving a directional antenna to track and align a target; servo system reports azimuth angle A when directional antenna tracks alignment target₁；

(208) The azimuth reported by an initial azimuth superposition servo system of the antenna zero is used as a geographical azimuth A of the airplane:

A＝A₀+A₁。

further, the specific mode of the step (3) is as follows:

(301) calculating coordinates (x, y and z) of the target unmanned aerial vehicle under a station center coordinate system of the ground measurement and control station:

in the formula: q is the elevation angle of the target unmanned aerial vehicle, the initial value is 0, r is the distance from the target unmanned aerial vehicle to the ground measurement and control station, and A is the azimuth angle of the target unmanned aerial vehicle;

(302) calculating coordinates (X, Y, Z) of the target unmanned aerial vehicle under a space rectangular coordinate system:

in the formula:is the radius of curvature of the prime;is the square of the first eccentricity, a is the ellipsoid major semi-axis, and b is the ellipsoid minor semi-axis; B. l, H the initial value is latitude B of ground measurement and control station₀Longitude L, longitude₀And height H₀；

(303) Calculating geodetic coordinates (B) of the target drone_T、L_T、H_T)：

(304) Judgment of H-H_TIf the value is less than the threshold value, go to step (306) if yes, otherwise go to step (305);

(305) calculating the correction d of the elevation angle_q＝(H-H_T) R, and let q be q + d_q，B＝B_T，L＝L_T，H＝H_TRepeating the steps (301) to (304) to perform iterative calculation;

(306) outputting geodetic coordinates (B) of the target drone under WGS84_T、L_T) And emergency navigation data are provided for the unmanned aerial vehicle.

The invention has the beneficial effects that:

1. the method is simple, convenient for programming execution and easy to realize.

2. The invention can provide emergency navigation information for the unmanned aerial vehicle when the satellite navigation signal is interfered.

Drawings

Fig. 1 is a flowchart of an emergency navigation method according to an embodiment of the present invention.

Fig. 2 is a processing flow chart of a single-pulse tracking angle measurement signal of the ground measurement and control station in the embodiment of the invention.

Fig. 3 is a flowchart of resolving a target latitude and longitude in an embodiment of the present invention.

Detailed Description

The technical scheme of the invention is further explained by combining the attached drawings and the detailed implementation mode.

As shown in fig. 1, an emergency navigation method based on a data link of an unmanned aerial vehicle includes the following steps:

(1) and the ranging of the unmanned aerial vehicle is realized by utilizing an uplink bidirectional link and a downlink bidirectional link of the unmanned aerial vehicle data link. The concrete mode is as follows:

(1.1) in the data chain of the unmanned aerial vehicle, a remote telemetry data frame head is generally adopted as a ranging pulse. And starting the timer 1 when the ground measurement and control station sends the head of the uplink remote control data frame.

And (1.2) starting the timer 2 when the airborne measurement and control terminal receives the head of the uplink remote control data frame.

And (1.3) stopping the timer 2 when the airborne measurement and control terminal sends the downlink telemetering data frame header, and simultaneously sending the timing time T2 of the timer 2 to the ground measurement and control station through downlink telemetering.

And (1.4) when the ground measurement and control station receives the head of the downlink telemetry data frame, stopping the timer 1 and simultaneously outputting the timing time T1 of the timer 1.

And (1.5) (T1-T2) correcting the ranging value to zero and removing the processing time delay of the equipment for the two-way transmission time of the remote control and telemetry radio signal and the processing time delay tau of the equipment. Knowing the transmission speed C of the electric wave in the free space, the distance from the unmanned aerial vehicle to the ground measurement and control station can be obtained:

r＝(T1-T2-τ)*C/2。

and (1.6) analyzing and calculating according to the frame period of the remote control and telemetry data frame and the action distance of the link, eliminating a fuzzy value and smoothing the ranging value.

(2) The single-pulse self-tracking function of the directional antenna of the ground measurement and control station of the unmanned aerial vehicle is utilized to realize the angle measurement of the unmanned aerial vehicle. The concrete mode is as follows:

(2.1) carrying out initial calibration on the ground measurement and control station, and determining the latitude, longitude and altitude coordinates (B) of the ground station₀、L₀、H₀) Initial azimuth A of antenna null₀Distance zeroing and reading the target aircraft altitude H from the telemetry.

And (2.2) receiving the downlink radio frequency signal of the unmanned aerial vehicle by the directional antenna of the ground measurement and control station. The amplitude comparison monopulse antenna receives signals through two bias feed horns, and the phase comparison monopulse antenna receives signals through two sub-arrays arranged at a certain interval; the two paths of signals generate a sum path signal and a difference path signal through a high-frequency sum and difference device.

And (2.3) carrying out 0-pi modulation on the difference signal by using a low-frequency (1-10) kHz square wave.

And (2.4) synthesizing the modulated difference path signal and the modulated sum path signal through a coupler, and selecting the coupling degree between (-6 to-14) dB to form a single-channel carrier signal.

And (2.5) carrying out low-noise amplification and frequency conversion on the synthesized single-channel signal to obtain an intermediate-frequency signal with a sufficiently strong amplitude, and then sending the intermediate-frequency signal to a tracking receiver.

(2.6) carrying out coherent amplitude detection on the signal by the tracking receiver, and taking out a low-frequency modulation signal; and then, carrying out synchronous detection on the reference square wave signal to separate the azimuth angle error voltage signal.

And (2.7) sending the azimuth angle error signal to an antenna servo to carry out closed-loop control, and driving a directional antenna to track and align the target. Servo system reports azimuth angle A when directional antenna tracks alignment target₁；

(2.8) the geographical azimuth A of the airplane is the initial azimuth A reported by the antenna null position superposition servo system₀+A₁。

(3) And calculating the longitude and latitude coordinates of the unmanned aerial vehicle by using the known coordinates of the ground measurement and control station and the distance and azimuth angle for observing the unmanned aerial vehicle. The concrete mode is as follows:

(3.1) solving the longitude and latitude of the target airplane, as shown in figure 2. Assuming that the elevation angle q of the target point is 0, the data is known: geodetic coordinate B of measurement and control station under WGS84 coordinate system₀、L₀、H₀Distance r, azimuth A, and ground height H of the target point.

And (3.2) according to the formula (1), the coordinates (x, y and z) of the target point in the station center coordinate system of the measurement and control station can be obtained.

In the formula: q is the elevation of the target, r is the distance, and A is the azimuth.

(3.3) obtaining the target compound from the formula (2)Coordinates (X) of output target point under space rectangular coordinate system_T、Y_T、Z_T)。

In the formula: b is₀、L₀、H₀The latitude, longitude and altitude of the ground measurement and control station.

Is the radius of curvature of the prime;is the square of the first eccentricity, a is the ellipsoid major semi-axis, and b is the ellipsoid minor semi-axis.

(3.4) obtaining the geodetic coordinate B of the target point according to the formula (3)_T、L_T、H_T

(3.5) judgment of (H-H)_T) And (4) whether the iteration precision eps is smaller than the iteration precision eps (0.000001 can be taken), if so, outputting the coordinates, namely the finally obtained geodetic coordinates, and otherwise, turning to the next step.

(3.6) calculating the correction number d of the elevation angle_q＝(H-H_T) R, then q is q + d_qThe iterative calculation is continued by the equation (2).

Finally, the output target aircraft is geodetic (B) under WGS84_T、L_T) And providing emergency navigation data for the aircraft.

The unmanned aerial vehicle data link is the kite line of unmanned aerial vehicle, provides the unmanned aerial vehicle and goes upward remote control, down telemetering measurement and reconnaissance information transmission function. The invention uses the uplink and downlink bidirectional links to measure the distance from the unmanned aerial vehicle to the ground measurement and control station; the ground measurement and control station adopts a directional antenna to receive downlink signals of the unmanned aerial vehicle, and can measure the azimuth angle of the unmanned aerial vehicle through a monopulse self-tracking function; through to unmanned aerial vehicle real-time range finding, angle measurement, calculate unmanned aerial vehicle's real-time longitude and latitude coordinate, can provide emergent navigation information for unmanned aerial vehicle when satellite navigation signal receives the interference.

It should be noted that the above-described embodiments are intended to enable any person skilled in the art to make or use the invention, and that various modifications to these embodiments will be apparent to those skilled in the art. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.