阅读说明：本技术 一种基于时差测量的小型无人机信号定位系统及方法 (Small unmanned aerial vehicle signal positioning system and method based on time difference measurement ) 是由 李晋徽 刘阳 晋晓曦 常凯 赵健 牛余凯 于 2020-12-17 设计创作，主要内容包括：本发明属于电子信息技术技术领域,具体涉及一种基于时差测量的小型无人机信号定位系统及方法。本发明包括分布式基站型电子侦察设备组和定位处理设备,分布式基站型电子侦察设备组与定位处理设备通过网络连接；分布式基站型电子侦察设备组接收无人机的测控信号,并对接收的无人机测控信号提取到达时差；定位处理设备通过提取的到达时差完成定位处理和解算工作。本发明通过基于分布式多站侦收、信号相关、时差测量的方式,实现对目标信号的准确定位。(The invention belongs to the technical field of electronic information, and particularly relates to a small unmanned aerial vehicle signal positioning system and method based on time difference measurement. The system comprises a distributed base station type electronic reconnaissance equipment group and positioning processing equipment, wherein the distributed base station type electronic reconnaissance equipment group is connected with the positioning processing equipment through a network; the distributed base station type electronic reconnaissance equipment group receives the measurement and control signals of the unmanned aerial vehicle and extracts arrival time difference from the received measurement and control signals of the unmanned aerial vehicle; and the positioning processing equipment finishes positioning processing and resolving work through the extracted arrival time difference. The invention realizes the accurate positioning of the target signal by a mode based on distributed multi-station detection and reception, signal correlation and time difference measurement.)

1. The utility model provides a small unmanned aerial vehicle signal positioning system based on time difference is measured which characterized in that: the system comprises a distributed base station type electronic reconnaissance equipment group (1) and positioning processing equipment (2), wherein the distributed base station type electronic reconnaissance equipment group (1) is connected with the positioning processing equipment (2) through a network; the distributed base station type electronic reconnaissance equipment group (1) receives the measurement and control signals of the unmanned aerial vehicle (3) and extracts arrival time difference from the received measurement and control signals of the unmanned aerial vehicle; and the positioning processing equipment finishes positioning processing and resolving work through the extracted arrival time difference.

2. The system of claim 1, wherein the system comprises: the base station type electronic reconnaissance equipment group (1) comprises 2 pieces of electronic reconnaissance equipment which are respectively a first electronic reconnaissance equipment and a second electronic reconnaissance equipment, wherein each piece of first electronic reconnaissance equipment and each piece of second electronic reconnaissance equipment respectively comprise a receiver and a CPU board.

3. The system of claim 2, wherein the system comprises: in the same base station type electronic reconnaissance equipment group, the receivers of the two pieces of electronic reconnaissance equipment are the same, and the CPU boards are different in composition.

4. The system of claim 3, wherein the system comprises: the receiver is used for receiving, amplifying low-noise power, filtering, A/D converting and digital down-conversion of the received signals, and converting the signals into time domain IQ data of zero intermediate frequency.

5. The system of claim 3, wherein the system comprises: in the first electronic reconnaissance equipment, a CPU board comprises a positioning parameter estimation module and a sensor, and the sensor is used for realizing fine synchronization of the first electronic reconnaissance equipment and the second electronic reconnaissance equipment in each base station type electronic reconnaissance equipment group and coarse synchronization between the base station type electronic reconnaissance equipment groups; and the positioning parameter estimation module carries out positioning parameter estimation according to the signals of the first electronic reconnaissance equipment and the second electronic reconnaissance equipment in the same time period, so as to obtain the time difference of arrival.

6. The system of claim 3, wherein the system comprises: for the second electronic spy device, the CPU board contains a sensor for fine synchronization with the first electronic spy device.

7. The method for positioning a signal positioning system of a drone based on time difference measurement according to any one of claims 1 to 6, characterized in that: the method comprises the following steps:

step 1, each base station type electronic reconnaissance equipment group (1) respectively reconnaissance unmanned aerial vehicle measurement and control signals

The positioning processing equipment (2) issues a positioning instruction, wherein the positioning instruction comprises target signal frequency, bandwidth and working frequency range parameters, two electronic reconnaissance equipment of each base station type electronic reconnaissance equipment group (1) simultaneously receive a measurement and control signal of a target unmanned aerial vehicle (3), amplify low noise power, filter, convert A/D (analog to digital) and convert the measurement and control signal into zero intermediate frequency time domain IQ (in-phase quadrature) data, in each base station type electronic reconnaissance equipment group (1), second electronic reconnaissance equipment sends the IQ data to first electronic reconnaissance equipment, and the first electronic reconnaissance equipment is responsible for estimating arrival time difference of the two groups of received IQ data;

step 2, each base station type electronic reconnaissance equipment group (1) calculates positioning parameters by using a time-frequency difference detection algorithm based on a mutual fuzzy function

In each base station type electronic reconnaissance equipment group (1), the first electronic reconnaissance equipment is a reference station, two-dimensional matching correlation processing of time difference and frequency difference is carried out on the two received signals by utilizing a mutual fuzzy function, and TDOA and FDOA estimated values, namely arrival time difference and arrival frequency difference, are obtained by searching the positions of peak values;

step 3, each base station type electronic reconnaissance equipment group (1) sends the measured time difference to the positioning processing equipment (2), and the positioning processing equipment (2) constructs a TDOA (time difference of arrival) positioning equation group and a solution equation to realize target positioning

The positioning processing equipment (2) firstly establishes a TDOA positioning equation by using the arrival time difference transmitted by each base station type electronic reconnaissance equipment group (1) at the same time, and the positions of two pieces of electronic reconnaissance equipment in each base station type electronic reconnaissance equipment group (1) are respectively expressed as s₁＝[x₁,y₁,z₁]And s₂＝[x₂,y₂,z₂]The position of the target drone to be estimated is denoted as u ═ x, y, z]The above positions all adopt a geocentric rectangular coordinate system, and the distance difference of the unmanned aerial vehicle signal reaching two electronic reconnaissance devices is as follows:

the above equation is the TDOA positioning equation, i represents the number of the scout group, i is 1,2, 3, c is the speed of the electromagnetic wave propagating in the medium, the positioning equations of the 3 base station type electronic scout device groups (1) form a positioning equation group,

assuming that the longitude of a point on the earth surface is L, the latitude is B and the elevation is H, under the WGS-84 ellipsoid model, the relationship between the geocentric rectangular coordinate of the point and the geodetic longitude and latitude height coordinates is

Wherein e is the first eccentricity of the ellipsoid, e²＝(a²-b²)/a²；

a is the major semi-axis of the ellipsoid, 6378.137 km; b is the minor semi-axis of the ellipsoid 6356.752314 km;

n is the curvature radius of the prime circle of the ellipsoid, and N is a/[1-e ]²(sinB)²]^1/2；

Reasonably estimating the height value of the unmanned aerial vehicle to be H ^ 300 meters; suppose the latitude range of the monitoring area is [ B ]₁,B₂]If so, the average longitude and latitude B ^ of the monitoring area is equal to (B)₁+B₂) 2; b ^ and H ^ are converted into a geocentric rectangular coordinate system by using formula 4, the obtained value is used as the estimated value of the z coordinate of the unmanned aerial vehicle, the time difference positioning equation set is simplified into a two-dimensional equation set, and finally the equation is solved, so that the target position u ═ x, y and z can be solved]。

8. The positioning method according to claim 7, characterized in that: in the step 2, specifically:

let the measurement and control signal of the unmanned aerial vehicle (3) be s (n), and the received signals of the first electronic reconnaissance equipment and the second electronic reconnaissance equipment in any base station type electronic reconnaissance equipment group (1) can be expressed as

In the formula, mu₁And mu₂Representing the path gain complex coefficients of the signal to the two electronic scout devices; k and v respectively represent the time delay and the Doppler frequency difference of signals received by the two electronic reconnaissance devices; n is₁(n) and n₂(n) the mutual fuzzy functions of the signals received by the two electronic scout devices are defined as follows

In the formula (f)_sFor the sampling rate, N is the number of sampling points

When A (k, v) reaches the peak value, the arrival time difference and the arrival frequency difference can be obtained through k and v, and the total sampling duration is T, the number of sampling points N is Tf_sThe time difference of arrival τ is k/f_sSum-arrival frequency difference f ═ vf_s。

Technical Field

The invention belongs to the technical field of electronic information, and particularly relates to a small unmanned aerial vehicle signal positioning system and method based on time difference measurement.

Background

The target is found by reconnaissance of the measurement and control signals of the small unmanned aerial vehicle, and the method is an important means for preventing and controlling the small unmanned aerial vehicle. Because the signal communication of the unmanned aerial vehicle usually adopts spread spectrum and frequency hopping technology, when the electromagnetic environment is more complicated, the existing electronic reconnaissance and direction finding means face the problem that the measurement and control signals are difficult to reconnaissance and find; and the problems of poor direction finding precision and low positioning accuracy exist under the influence of multipath and the like.

The small unmanned aerial vehicle has low fund threshold, is easy and convenient to operate and easy to learn, the safety performance of the unmanned aerial vehicle is imperfect, the operation standard degree of an operator of the unmanned aerial vehicle is difficult to guarantee, and the like, so that the huge supervision difficulty is brought to the unmanned aerial vehicle industry. The illegal sensitive area that gets into of unmanned aerial vehicle, "flies" and scrambles events such as civil aviation order, unmanned aerial vehicle trouble/fall are rare often, have triggered a series of moral, law, safety problem, and unmanned aerial vehicle's supervision problem is waited to solve urgently, and the prerequisite of control can realize accurate positioning to the unmanned aerial vehicle signal.

Therefore, a system and a method for positioning signals of a small unmanned aerial vehicle are needed to realize accurate positioning of signals of the unmanned aerial vehicle.

Disclosure of Invention

The invention aims to: the invention provides a small unmanned aerial vehicle signal positioning system and method based on time difference measurement, which can realize accurate positioning of a target signal through a mode based on distributed multi-station detection and reception, signal correlation and time difference measurement.

The technical scheme adopted by the invention is as follows:

a small unmanned aerial vehicle signal positioning system based on time difference measurement comprises a distributed base station type electronic reconnaissance equipment group and positioning processing equipment, wherein the distributed base station type electronic reconnaissance equipment group is connected with the positioning processing equipment through a network; the distributed base station type electronic reconnaissance equipment group receives the measurement and control signals of the unmanned aerial vehicle and extracts arrival time difference from the received measurement and control signals of the unmanned aerial vehicle; and the positioning processing equipment finishes positioning processing and resolving work through the extracted arrival time difference.

The base station type electronic reconnaissance equipment group comprises 2 pieces of electronic reconnaissance equipment which are respectively a first electronic reconnaissance equipment and a second electronic reconnaissance equipment, wherein each piece of first electronic reconnaissance equipment and each piece of second electronic reconnaissance equipment respectively comprise a receiver and a CPU board.

In the same base station type electronic reconnaissance equipment group, the receivers of the two pieces of electronic reconnaissance equipment are the same, and the CPU boards are different in composition.

The receiver is used for receiving, amplifying low-noise power, filtering, A/D converting and digital down-conversion of the received signals, and converting the signals into time domain IQ data of zero intermediate frequency.

In the first electronic reconnaissance equipment, a CPU board comprises a positioning parameter estimation module and a sensor, and the sensor is used for realizing fine synchronization of the first electronic reconnaissance equipment and the second electronic reconnaissance equipment in each base station type electronic reconnaissance equipment group and coarse synchronization between the base station type electronic reconnaissance equipment groups; and the positioning parameter estimation module carries out positioning parameter estimation according to the signals of the first electronic reconnaissance equipment and the second electronic reconnaissance equipment in the same time period, so as to obtain the time difference of arrival.

For the second electronic spy device, the CPU board contains a sensor for fine synchronization with the first electronic spy device.

The positioning method of the small unmanned aerial vehicle signal positioning system based on time difference measurement comprises the following steps:

step 1, each base station type electronic reconnaissance equipment group respectively reconnaissance unmanned aerial vehicle measurement and control signals

The method comprises the steps that positioning processing equipment issues a positioning instruction, wherein the positioning instruction comprises target signal frequency, bandwidth and working frequency range parameters, two electronic reconnaissance equipment of each base station type electronic reconnaissance equipment group simultaneously receive a measurement and control signal of a target unmanned aerial vehicle, amplify low-noise power, filter, convert A/D (analog/digital) and carry out digital down-conversion, and convert the measurement and control signal into zero-intermediate-frequency time domain IQ (in-phase quadrature) data, in each base station type electronic reconnaissance equipment group, second electronic reconnaissance equipment sends the IQ data to first electronic reconnaissance equipment, and the first electronic reconnaissance equipment is responsible for carrying out arrival time difference estimation on the two;

step 2, each base station type electronic reconnaissance equipment group calculates positioning parameters by using time-frequency difference detection algorithm based on mutual fuzzy function

In each base station type electronic reconnaissance equipment group, the first electronic reconnaissance equipment is a reference station, two-dimensional matching correlation processing of time difference and frequency difference is carried out on the two received signals by using a mutual fuzzy function, and TDOA and FDOA estimated values, namely arrival time difference and arrival frequency difference, are obtained by searching the positions of peak values;

step 3, each base station type electronic reconnaissance equipment group sends the measured time difference to positioning processing equipment, and the positioning processing equipment constructs a TDOA positioning equation group and a solving equation to realize target positioning

The positioning processing equipment firstly establishes a TDOA positioning equation by using the arrival time difference sent by each base station type electronic reconnaissance equipment group at the same time, and the positions of two pieces of electronic reconnaissance equipment in each base station type electronic reconnaissance equipment group are respectively expressed as s₁＝[x₁,y₁,z₁]And s₂＝[x₂,y₂,z₂]The position of the target drone to be estimated is denoted as u ═ x, y, z]The above positions all adopt a geocentric rectangular coordinate system, and the distance difference of the unmanned aerial vehicle signal reaching two electronic reconnaissance devices is as follows:

the above equation is the TDOA positioning equation, i represents the number of the scout group, i is 1,2, 3, c is the speed of the electromagnetic wave propagating in the medium, the positioning equations of the 3 base station type electronic scout device groups form a positioning equation group,

assuming that the longitude of a point on the earth surface is L, the latitude is B and the elevation is H, under the WGS-84 ellipsoid model, the relationship between the geocentric rectangular coordinate of the point and the geodetic longitude and latitude height coordinates is

Wherein e is the first eccentricity of the ellipsoid, e²＝(a²-b²)/a²；

a is the major semi-axis of the ellipsoid, 6378.137 km; b is the minor semi-axis of the ellipsoid 6356.752314 km;

n is the curvature radius of the prime circle of the ellipsoid, and N is a/[1-e ]²(sinB)²]^1/2。

Reasonably estimating the height value of the unmanned aerial vehicle to be H ^ 300 meters; suppose the latitude range of the monitoring area is [ B ]₁,B₂]If so, the average longitude and latitude B ^ of the monitoring area is equal to (B)₁+B₂) 2; b ^ and H ^ are converted into a geocentric rectangular coordinate system by using formula 4, the obtained value is used as the estimated value of the z coordinate of the unmanned aerial vehicle, the time difference positioning equation set is simplified into a two-dimensional equation set, and finally the equation is solved, so that the target position u ═ x, y and z can be solved]。

In the step 2, specifically:

let the unmanned aerial vehicle measure and control signal be s (n), and the signals received by the first electronic reconnaissance equipment and the second electronic reconnaissance equipment in any base station type electronic reconnaissance equipment group can be expressed as

In the formula, mu₁And mu₂Representing the path gain complex coefficients of the signal to the two electronic scout devices; k and v respectively represent the time delay and the Doppler frequency difference of signals received by the two electronic reconnaissance devices; n is₁(n) and n₂(n) the mutual fuzzy functions of the signals received by the two electronic scout devices are defined as follows

In the formula (f)_sFor the sampling rate, N is the number of sampling points

When A (k, v) reaches the peak value, the arrival time difference and the arrival frequency difference can be obtained through k and v, and the total sampling duration is T, the number of sampling points N is Tf_sThe time difference of arrival τ is k/f_sSum-arrival frequency difference f ═ vf_s。

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention provides a small unmanned aerial vehicle signal positioning system and a method based on time difference measurement.A distributed base station type electronic reconnaissance device is used for reconnaissance of a small unmanned aerial vehicle measurement and control signal and is connected to a positioning processing device through a network, the positioning processing device comprehensively adopts a time-frequency difference detection and time difference positioning technology based on a mutual fuzzy function to intensively complete positioning processing and resolving work, and the detection capability, the positioning precision and the accuracy of the small unmanned aerial vehicle measurement and control signal are improved;

(2) the invention provides a small-sized unmanned aerial vehicle signal positioning system and method based on time difference measurement.A positioning parameter extraction technology adopts a mutual fuzzy function (CAF) method to carry out TDOA and FDOA combined parameter estimation on a received signal, and can obtain a time difference of arrival and a frequency difference of arrival with higher accuracy;

(3) the invention provides a small unmanned aerial vehicle signal positioning system and method based on time difference measurement, which utilize the arrival time difference calculated by a distributed base station to construct a positioning equation set and solve the positioning equation set, thereby realizing target positioning;

(4) the invention provides a small unmanned aerial vehicle signal positioning system and method based on time difference measurement, which can effectively solve the multipath problem faced by signal positioning in urban environment, can realize continuous positioning, have high positioning precision and strong anti-interference capability, and are very suitable for positioning an unmanned aerial vehicle;

(5) the invention provides a small unmanned aerial vehicle signal positioning system and method based on time difference measurement, which can be widely applied to the field of unmanned aerial vehicle control.

Drawings

Fig. 1 is a structural diagram of a signal positioning system of a small unmanned aerial vehicle based on time difference measurement, provided by the invention;

FIG. 2 is a block diagram of the components and the working principle of a signal positioning system of a small unmanned aerial vehicle based on time difference measurement provided by the invention;

FIG. 3 is a flow chart of a signal positioning method for a small unmanned aerial vehicle based on time difference measurement according to the present invention;

in the figure: 1-base station type electronic reconnaissance equipment group, 2-positioning processing equipment and 3-unmanned aerial vehicle.

Detailed Description

The following describes a signal positioning system and method of a drone based on time difference measurement in detail with reference to the accompanying drawings and specific embodiments.

As shown in fig. 1, the small-sized unmanned aerial vehicle signal positioning system based on time difference measurement provided by the invention comprises a distributed base station type electronic reconnaissance equipment group 1 and a positioning processing device 2, wherein the distributed base station type electronic reconnaissance equipment group 1 is connected with the positioning processing device 2 through a network; the distributed base station type electronic reconnaissance equipment group 1 receives the measurement and control signals of the unmanned aerial vehicle 3, and extracts arrival time difference from the received measurement and control signals of the unmanned aerial vehicle through a time-frequency difference detection technology based on a mutual fuzzy function; the positioning processing equipment completes positioning processing and resolving work through a time difference positioning technology.

As a specific embodiment, as shown in fig. 2, in the small-sized unmanned aerial vehicle signal positioning system based on time difference measurement provided by the present invention, the distributed base station includes 3 base station type electronic reconnaissance device groups, each base station type electronic reconnaissance device group includes 2 electronic reconnaissance devices, which are a first electronic reconnaissance device and a second electronic reconnaissance device, respectively, each of the first electronic reconnaissance device and the second electronic reconnaissance device includes a receiver and a CPU board, respectively, in the same base station type electronic reconnaissance device group, the receivers of the two electronic reconnaissance devices are the same, and the compositions of the CPU boards are slightly different, where:

the receiver is used for receiving, amplifying low noise power, filtering, A/D converting, digital down-conversion and other processing of the received signal, and converting the signal into time domain IQ data of zero intermediate frequency.

For the first electronic reconnaissance equipment, the CPU board mainly comprises a positioning parameter estimation module and a sensor, and the sensor is used for realizing fine synchronization of the first electronic reconnaissance equipment and the second electronic reconnaissance equipment in each base station type electronic reconnaissance equipment group and coarse synchronization between the base station type electronic reconnaissance equipment groups; the positioning parameter estimation module carries out positioning parameter estimation according to signals of the first electronic reconnaissance device and the second electronic reconnaissance device in the same time period, and arrival time difference is obtained; for the second electronic scout device, the CPU board mainly contains sensors for fine synchronization with the first electronic scout device.

The positioning processing equipment 2 is responsible for inquiring the equipment state of each base station type electronic reconnaissance equipment group 1, controlling each base station type electronic reconnaissance equipment group 1 to perform reconnaissance and positioning parameter extraction on the measurement and control signals of the target unmanned aerial vehicle 3, establishing an equation set and solving an equation according to the positioning parameter estimation result, and acquiring and displaying the target position; the operator can input information such as frequency, bandwidth, working frequency band and the like of the measurement and control signal of the target unmanned aerial vehicle in the display and control software of the positioning processing equipment 2.

As shown in fig. 3, in the method for positioning a signal of a small unmanned aerial vehicle based on time difference measurement provided by the present invention, each base station type electronic reconnaissance device group 1 performs TDOA and FDOA joint parameter estimation on a received measurement and control signal of the unmanned aerial vehicle 3; then, the positioning processing device 2 constructs a TDOA positioning equation set according to the time difference measurement result, and calculates to obtain the target position after solving. The positioning process is as follows:

step 1, each base station type electronic reconnaissance equipment group 1 respectively reconnaissance unmanned aerial vehicle measurement and control signals.

As shown in fig. 2, a positioning instruction is issued by the positioning processing device 2, wherein the positioning instruction includes target signal frequency, bandwidth, and operating frequency band parameters. The two electronic reconnaissance devices of each base station type electronic reconnaissance device group 1 simultaneously receive the measurement and control signals of the target unmanned aerial vehicle 3, amplify the low-noise power, filter, convert the A/D conversion, convert the digital down-conversion and the like, and convert the signals into time domain IQ data of zero intermediate frequency. In each base station type electronic scout equipment group 1, the second electronic scout equipment sends the IQ data to the first electronic scout equipment 1, and the first electronic scout equipment is responsible for estimating the arrival time difference of the two groups of received IQ data.

And 2, calculating positioning parameters by each base station type electronic reconnaissance equipment group 1 by using a time-frequency difference detection algorithm based on a mutual fuzzy function.

In each base station type electronic reconnaissance equipment group 1, the first electronic reconnaissance equipment is a reference station, two-dimensional matching correlation processing of time difference and frequency difference is carried out on the two received signals by using a mutual fuzzy function (CAF), and TDOA and FDOA estimated values, namely arrival time difference and arrival frequency difference, are obtained by searching the positions of peak values.

Let the measurement and control signal of the unmanned aerial vehicle 3 be s (n), and the received signals of the first electronic reconnaissance equipment and the second electronic reconnaissance equipment in any base station type electronic reconnaissance equipment group 1 can be expressed as

In the formula, mu₁And mu₂Representing the path gain complex coefficients of the signal to the two electronic scout devices; k and v respectively represent the time delay and the Doppler frequency difference of signals received by the two electronic reconnaissance devices; n is₁(n) and n₂And (n) the observation noises of the two electronic reconnaissance devices respectively. The mutual ambiguity function (CAF) of the signals received by the two electronic spy devices is defined as follows

In the formula (f)_sAnd N is the number of sampling points.

When A (k, v) reaches the peak value, the arrival time difference and the arrival frequency difference can be obtained through k and v. If the total sampling duration is T, the number of sampling points N is Tf_sThe time difference of arrival τ is k/f_sSum-arrival frequency difference f ═ vf_s。

And 3, each base station type electronic reconnaissance equipment group 1 sends the measured time difference to the positioning processing equipment 2, and the positioning processing equipment 2 constructs a TDOA positioning equation set and a solution equation to realize target positioning.

The location processing device 2 first establishes a TDOA location equation using the arrival time difference transmitted at the same time by each base station type electronic reconnaissance device group 1. In each base station type electronic scout equipment group 1, the positions of two electronic scout equipments are respectively indicated as s₁＝[x₁,y₁,z₁]And s₂＝[x₂,y₂,z₂]The position of the target drone to be estimated is denoted as u ═ x, y, z]And all the positions adopt a geocentric rectangular coordinate system. Unmanned aerial vehicleThe difference in the distances from the number to the two electronic scout devices is as follows:

the above equation is the TDOA positioning equation, i represents the number of the scout group, i is 1,2, 3, c is the speed of electromagnetic wave propagating in the medium, and the positioning equations of the 3 base station type electronic scout device groups 1 form a positioning equation group.

Assuming that the longitude of a point on the earth surface is L, the latitude is B and the elevation is H, under the WGS-84 ellipsoid model, the relationship between the geocentric rectangular coordinate of the point and the geodetic longitude and latitude height coordinates is

Wherein e is the first eccentricity of the ellipsoid, e²＝(a²-b²)/a²；

a is the major semi-axis of the ellipsoid, 6378.137 km; b is the minor semi-axis of the ellipsoid 6356.752314 km;

n is the curvature radius of the prime circle of the ellipsoid, and N is a/[1-e ]²(sinB)²]^1/2。

The maximum flying height of the civil light unmanned aerial vehicle in the current market is below 500 meters, so the height value of the unmanned aerial vehicle is reasonably estimated to be H ^ 300 meters. Suppose the latitude range of the monitoring area is [ B ]₁,B₂]If so, the average longitude and latitude B ^ of the monitoring area is equal to (B)₁+B₂)/2. B ^ and H ^ are converted into a geocentric rectangular coordinate system by using formula 4, the obtained value is used as the estimated value of the z coordinate of the unmanned aerial vehicle, the time difference positioning equation set is simplified into a two-dimensional equation set, and finally the equation is solved, so that the target position u ═ x, y and z can be solved]。

The time difference measurement-based small unmanned aerial vehicle signal positioning system and method provided by the invention can continuously receive unmanned aerial vehicle measurement and control signals, extract positioning parameters, construct and solve positioning equations, and can realize continuous positioning on the premise of ensuring high positioning accuracy.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the technical scope of the present invention.