WO2017066915A1

WO2017066915A1 - Method and device for posture measurement in satellite navigation and unmanned aerial vehicle

Info

Publication number: WO2017066915A1
Application number: PCT/CN2015/092243
Authority: WO
Inventors: 林灿龙; 张伟
Original assignee: 深圳市大疆创新科技有限公司
Priority date: 2015-10-20
Filing date: 2015-10-20
Publication date: 2017-04-27
Also published as: CN107003386A; CN107003386B

Abstract

A method and device for posture measurement in satellite navigation and an unmanned aerial vehicle, which are used to improve the accuracy of obtained posture data and simplify the method for posture measurement. The method comprises: obtaining original observations of a satellite signal, an ephemeris and the position of an antenna, wherein the original observations comprise a carrier observation value and a pseudorange observation value (110); according to the ephemeris and the position of the antenna, obtaining a unit vector from the antenna to a satellite; obtaining a carrier double difference based on the carrier observation value, and obtaining a unit vector double difference from the antenna to the satellite based on the ephemeris and the position of the antenna (120); solving an integer ambiguity based on the carrier double difference, the unit vector double difference from the antenna to the satellite, and the baseline length between two antennas (130); obtaining a baseline vector between three antennas based on the integer ambiguity, the unit vector double difference from the antenna to the satellite and the carrier double difference (140); and obtaining a posture angle based on the position of the antenna and the baseline vector between the three antennas (150).

Description

Satellite navigation attitude measuring method and device and drone

Technical field

The invention relates to the field of satellite navigation technology, and in particular to a satellite navigation attitude measuring method and device and a drone.

Background technique

Aircraft such as small drones are generally used to obtain heading information based on volume, cost, weight, etc., and use INS (Inertial Navigation System) to obtain aircraft attitude information. Among them, the compass achieves the pointing effect through the action of the earth's magnetic field, but the compass's measured heading includes the magnetic declination and cannot be used in the presence of magnetic field interference. The accuracy of the INS is not high, and the acquired pose data is difficult to use directly.

Summary of the invention

The embodiment of the invention provides a satellite navigation attitude measuring method and device and a drone to improve the accuracy of the obtained attitude data, and to simplify the attitude measuring method and reduce the cost.

A first aspect of the present invention provides a satellite navigation attitude determining method for testing a posture of a drone, wherein the drone is provided with three antennas not on the same straight line, and the method includes:

Obtaining raw observations of satellite signals, ephemeris, and locations of antennas, the raw observations including carrier observations and pseudorange observations;

Deriving the unit vector between the antenna and the satellite according to the position of the ephemeris and the antenna;

Based on the carrier observation, the carrier double difference is obtained, and the unit vector double difference of the antenna to the satellite is obtained based on the position of the ephemeris and the antenna;

The whole-circumference ambiguity is obtained based on the carrier double difference, the antenna-to-satellite unit vector double difference, and the baseline length between the two antennas;

Determining a baseline vector between the three antennas based on the whole-circumference ambiguity, antenna-to-satellite unit vector double difference, and carrier double difference;

The attitude angle is derived based on the position of the antenna and the baseline vector between the three antennas.

A second aspect of the present invention provides a satellite navigation apparatus for testing a posture of a drone, wherein the drone is provided with three antennas not on the same straight line, and the apparatus includes:

An acquisition module, configured to obtain a raw observation of a satellite signal, an ephemeris, and a position of an antenna, the original observation including a carrier observation and a pseudorange observation;

a calculation module for deriving a unit vector between the antenna and the satellite according to the position of the ephemeris and the antenna; deriving a carrier double difference based on the carrier observation, and obtaining a unit vector double difference of the antenna to the satellite based on the position of the ephemeris and the antenna; The whole-circumference ambiguity is obtained based on the carrier double difference, the antenna-to-satellite unit vector double difference, and the baseline length between the two antennas; based on the whole-circumference ambiguity, the antenna-to-satellite unit vector double difference, and the carrier double difference A baseline vector between the three antennas; the attitude angle is derived based on the position of the antenna and the baseline vector between the three antennas.

A third aspect of the present invention provides a drone, comprising: a body, at least three antennas disposed on the body and not on a same straight line, and the at least three antennas are respectively connected to at least three receivers, The at least three receivers are coupled to a flight control system, the flight control system for:

Obtaining the original observation of the satellite signal, the ephemeris, and the position of the antenna through the at least three receivers and the at least three antennas, the raw observations including carrier observations and pseudorange observations; according to ephemeris and antennas The position derives the unit vector between the antenna and the satellite; based on the carrier observation, the carrier double difference is obtained, and the unit vector double difference of the antenna to the satellite is obtained based on the position of the ephemeris and the antenna; the unit vector based on the carrier double difference and the antenna to the satellite Double-difference and baseline length between two antennas to obtain full-circumference ambiguity; base vector between three antennas based on the whole-circumference ambiguity, antenna-to-satellite unit vector double difference, and carrier double difference; The position and the baseline vector between the three antennas yield the attitude angle.

As can be seen from the above, the satellite navigation attitude measurement method according to the embodiment of the present invention uses data such as carrier double difference obtained from satellite signals to solve the whole-circumference ambiguity and the baseline vector between the antennas, and calculates the attitude angle according to the baseline vector. The following technical effects:

First, the satellite signal is used to test the attitude of the drone. Compared with the INS positioning, the accuracy of the attitude data is improved, and the problems of the magnetic declination and magnetic field interference of the compass pointing are avoided.

Second, by constructing the carrier phase double-difference equation, the least squares search method based on the baseline distance constraint is used to solve the whole-circumference ambiguity. On the one hand, it is suitable for the single-frequency receiver, which is lower than the dual-frequency receiver used in the prior art. On the other hand, the calculation method is simplified and the computational complexity is reduced.

DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following describes the embodiments and the prior art. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in FIG. Other drawings can be obtained from these figures.

1 is a flowchart of a satellite navigation attitude measurement method according to an embodiment of the present invention;

2 is a schematic diagram showing the relationship between a baseline vector and a satellite distance;

Figure 3 is a schematic diagram of a drone and an antenna;

4 is a schematic diagram of a UAV attitude solving process;

FIG. 5 is a schematic diagram of a satellite navigation apparatus according to a second embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is an embodiment of the invention, but not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of the present invention.

The technical solution of the embodiment of the invention is applicable to various unmanned aerial vehicles, such as unmanned aerial vehicles, unmanned vehicles, etc., especially the navigation and attitude measurement of various small unmanned aerial vehicles. The unmanned aerial vehicle may be a helicopter drone or a fixed-wing drone. Detailed description will be made below through specific embodiments.

A first embodiment of the present invention provides a satellite navigation attitude measurement method for testing a posture of a drone. In the embodiment of the present invention, GPS (Global Positioning System) is used to locate the attitude information of an aircraft such as a drone. At least three antennas not on the same straight line may be disposed on the drone, and each antenna is connected to one receiver. Taking three antennas on the drone as an example, three antennas are respectively connected to three receivers, three receivers are connected to one satellite navigation device, and the satellite navigation device is connected to a flight control system. Wherein, the receiver receives the satellite signal through the antenna, obtains the original observation, the ephemeris and the position of the antenna, and transmits the position to the satellite navigation device. The satellite navigation device may include an attitude solving processor for decomposing the attitude data of the drone according to the original observation of the acquired satellite signal, the ephemeris and the position of the antenna, and transmitting the attitude data to the flight control system. The flight control system can control the drone flight based on the obtained attitude data. Among them, the satellite navigation device can also be regarded as part of the flight control system. The method of the embodiment of the present invention may be performed by the satellite navigation device, or by the posture The state solver executes the processor.

Please refer to FIG. 1. The specific process of the satellite navigation attitude measurement method provided by the embodiment of the present invention may include:

101. Obtain original observations of satellite signals, ephemeris, and positions of antennas, the original observations including carrier observations and pseudorange observations.

Satellite navigation attitude measurement is based on carrier relative positioning technology. Carrier relative positioning uses two antennas to simultaneously receive GPS signals, and then calculates the baseline vectors (position vectors) of the two antennas through a relative positioning algorithm. Installing three GPS antennas can calculate two baseline vectors at specific locations to calculate the attitude of the carrier. The carrier error is in the millimeter level, so the accuracy of the baseline vector is also in the millimeter level. Under the premise of guaranteeing a certain baseline length (ie, the antenna distance), the GPS attitude can achieve high precision.

The GPS receiver can acquire satellite pseudorange observations, carrier observations, and satellite ephemeris. The satellite position can be calculated from the received ephemeris. As long as there are more than 4 satellite pseudoranges, the receiver's time, position and speed can be calculated. Therefore, the satellite navigation device can acquire the carrier observation value and the pseudorange observation value of the satellite signal, the position of the ephemeris and the antenna, and the time and speed of the receiver from the GPS receiver.

102. Obtain a unit vector between the antenna and the satellite according to the position of the ephemeris and the antenna; based on the carrier observation, the carrier double difference is obtained, and the unit vector double difference of the antenna to the satellite is obtained based on the position of the ephemeris and the antenna.

The carrier observation has higher measurement accuracy. After the receiver stably tracks the satellite signal, the fractional part of the carrier period and the subsequent carrier variation value can be obtained. However, the number of fixed carriers can not be determined and cannot be directly used. Single point positioning. The number of undetermined carriers in the whole week is called the full-circumference ambiguity. Since the pseudorange and carrier measurements contain errors, to achieve high-precision baseline vector measurements, carrier differential positioning must be used. The key to carrier differential positioning is to determine the full-circumference ambiguity.

The pseudorange and carrier observations contain three types of errors, listed below:

1. Satellite-related errors, including satellite ephemeris error, satellite clock error, satellite antenna phase center deviation, and relativistic effect error;

Second, errors related to signal propagation, including ionospheric delay error, tropospheric delay error, and signal multipath error;

Third, the error related to the receiving device, including the receiver clock difference, the antenna phase center deviation and the connection Receive noise measurement.

In the single point positioning, the first type of error can only correct the relativistic effect error, the second type of error can repair part of the ionospheric delay error and partial tropospheric delay error, and the third type of error is reduced by the hardware and software design of the receiver. The error of single point positioning can only guarantee the accuracy within 10m. The distance between two antennas installed by the drone will not exceed 10m. The coordinates of the two antennas cannot be determined by single point positioning, and then the direction is calculated.

For the two antennas not far apart, the first type and the second type of error have strong spatial correlation, and the error effects at the same time are basically the same. The difference in measured value is obtained by taking the difference between the measured values to obtain a new observation value, so as to eliminate the error. Differential relative positioning is the use of differential observations to calculate the vector between the antennas, including pseudorange differential positioning and carrier differential positioning. Since the measurement accuracy of the pseudorange is not high, it is the meter level, so the error of the pseudorange differential positioning is also the meter level. To achieve high-precision baseline vector measurements, carrier differential positioning is required.

The carrier difference observation is a new combined observation obtained by deriving the carrier phase observations of the same frequency in a certain way. Generally, the carrier phase double difference observation value is used, that is, the difference between the antennas is one time, the satellite related error and the signal propagation error can be eliminated, and the difference between the satellites can be eliminated, and the receiver clock difference can be eliminated.

103. Perform full-circumference ambiguity based on carrier double difference, antenna-to-satellite unit vector double difference, and baseline length between two antennas.

In the embodiment of the present invention, the whole-circumference ambiguity can be obtained based on the carrier double difference, the antenna-to-satellite unit vector double difference, and the baseline length between the two antennas. Preferably, the full-circumference ambiguity is solved by a least squares search method with a baseline distance constraint. This method is suitable for short-range fixed-length baseline attitudes and can be used with single-frequency receivers. Compared to the use of dual-frequency receivers, the use of a single-frequency receiver can effectively reduce costs.

104. Obtain a baseline vector between the three antennas based on the whole-circumference ambiguity, antenna-to-satellite unit vector double difference, and carrier double difference.

The whole-circumference ambiguity, the antenna-to-satellite unit vector double difference and the carrier double-difference are substituted into the constructed carrier phase double-difference equation to solve, and the baseline vector between the three antennas can be obtained.

105. Obtain an attitude angle based on the position of the antenna and a baseline vector between the three antennas.

Combine the position of the antenna with the baseline vector between the three antennas to obtain the attitude angle of the drone. The stated attitude angles include heading and pitch angles as well as roll angles.

Further, in some embodiments of the present invention, the least squares search method using a baseline distance constraint to solve the whole-circumference ambiguity may include: dividing the tracked satellite into a main star and a redundant star, where the main star includes Four, and one of the four main stars is used as a reference star, and the reference star has the highest elevation angle; constructing a double-difference equation of the reference star and other main stars to determine the double-difference ambiguity search range of the main star carrier double difference equation Calculating a possible solution of the baseline vector; constructing a carrier double difference equation of the reference star and the redundant star, and substituting the baseline vector possible solution into the redundant star carrier double difference equation to determine the double difference ambiguity of the redundant star; The double-difference ambiguity of the satellite determines the ambiguity of the whole week.

In some embodiments of the present invention, determining the whole-circumference ambiguity according to the double-difference ambiguity of all satellites may include: substituting the double-difference ambiguities of all satellites into a medium-carrier double-difference equation, and calculating a sum of squared residuals of the equations, In all possible solutions, the whole-circumference ambiguity corresponding to the sum of squares of the minimum residuals is taken as the solution to be determined. When multiple epochs obtain the same to-be-determined solution, it is confirmed that the to-be-determined solution is a fixed solution.

In some embodiments of the present invention, the baseline vector includes: a first baseline vector from a first antenna to a second antenna of the three antennas, and a second baseline vector of the first antenna to the third antenna; Deriving the attitude angle based on the position of the antenna and the baseline vector between the three antennas includes calculating a heading angle and a pitch of the drone based on the positions of the first antenna and the second antenna and the first baseline vector An angle of the drone of the drone is calculated based on the positions of the first and third antennas and the second baseline vector.

In some embodiments of the present invention, before the obtaining the original observation of the received satellite signal, the method further comprises: receiving, by the single frequency receiver, the satellite signal through the antenna.

In some embodiments of the present invention, the method further includes: fusing the obtained attitude angle and the inertial navigation data to obtain an optimized estimation of the attitude angle for performing the attitude control of the drone.

In some embodiments of the invention, the drone further includes an inertial measurement device, the inertial navigation data being measured by the inertial measurement device.

As can be seen from the above, the embodiment of the present invention discloses a satellite navigation attitude measurement method, which uses data such as carrier double difference obtained based on satellite signals to solve the whole-circumference ambiguity and the baseline vector between the antennas, and calculates the attitude angle according to the baseline vector. The technical solution has achieved the following technical effects:

1. Using satellite signals to test the attitude of the drone, improving the accuracy of the attitude data relative to the INS positioning. Degree, and avoid the problem that the compass points to the existing magnetic declination and magnetic field interference;

The technical solutions of the embodiments of the present invention are further described in detail below.

First, explain the column of the carrier phase difference equation.

1. Carrier phase single difference equation

As shown in Figure 2, the unit vector between antenna 1 and satellite k is

The unit vector between antenna 2 and satellite k is

For the distance from antenna 1 to satellite k minus the distance from antenna 2 to satellite k, b is the vector between the two antennas. When the distance between the two antennas is less than 40Km, it is much smaller than the distance from the antenna to the satellite (about 20000Km). It can be considered

then

Let the clock difference between antenna 1 and antenna 2 be Δt, then the single difference measurement model can be expressed as

(Formula 1)

Where λ ^k is the carrier wavelength of satellite k, f ^k is the carrier frequency, λ ^k ·f ^k =c, and c is the speed of light.

It is a single difference ambiguity. Consider b = (Δx ₁₂ , Δy ₁₂ ,, Δz ₁₂ ,),

Equation 1 can be rewritten as

(Formula 2)

2. Carrier phase double difference equation

The reference star is set to j. For the GPS system, the frequency of the same frequency point is the same, and the frequency change caused by Doppler influence is negligible, then the double difference observation model can be expressed as

(Formula 3)

among them

It is a double difference ambiguity.

Carrier phase double difference equation in the form of a matrix if there are multiple stars

y=Bb+Aa+e (4)

Where y is the double difference observation, which can be obtained based on the original observation, a is the whole week ambiguity, e is the noise, A and B can be understood as the coefficient matrix, specifically, A is the ambiguity weight matrix.

The main part of the noise e is the observation error. When the tracking loop is stable, it can be considered to be less than 1 mm, and it is unbiased white noise, and can be taken as 0 in the calculation. When the receiver keeps continuously observation of the satellite carrier, each element in the vector a is an integer and does not change with time and remains unchanged. The key to solving equation (4) is to solve the whole-circumference ambiguity a. After solving a solution, the baseline vector b can be calculated with an error of millimeters.

Second, solve the whole week ambiguity.

The key to solving the carrier-phase double-difference equation is to determine the full-circumference ambiguity. According to the invention, the installation position of the UAV antenna is fixed, and the baseline length is short, and the least square search method based on the baseline distance constraint is used to solve the whole-circumference ambiguity, which is suitable for the short-distance fixed-length baseline attitude measurement, and the single frequency can be used. Receiver.

In the carrier phase double difference observation equation, only three double difference ambiguity parameters are independent. Solving these three double-difference ambiguities can determine the baseline vector and then reverse the other unknown ambiguities. The least squares search method divides the observation satellite into four main stars and redundant stars, the four main stars include one reference star, and the other satellites construct a double difference equation with the reference star. After determining the ambiguity search range of the main star carrier phase double difference equation, the calculation base The line may be solved, and then substituted into the redundant star observation equation to determine the double-difference ambiguity of the redundant satellite.

The selection of the four main stars is very critical. The reference star generally selects the satellite with the highest elevation angle, and the other three select satellites with a certain elevation angle and carrier-to-noise ratio, and the GDOP (Geometric Dilution Precision) value is small.

Assuming that the baseline vector points from antenna 1 to antenna 2, the baseline length ranges from [d _min , d _max ], antenna 2 is constrained to a hollow sphere, the inner radius of the sphere is d _min , and the radius of the outer shell is d _max . The following analysis of the main star double difference ambiguity search range. The carrier phase double difference observation equation of the four main stars is as follows:

Formula (5)

Where λ is the carrier wavelength, the baseline vector b = (Δx, Δy, Δz) ^T _, (x _i , y _i , z _i ) ^T is the unit vector double difference of the antenna to the satellite, and N _i is the double difference ambiguity,

Is the carrier phase double difference observation in cycles, where i = 1, 2, 3. The baseline vector and the double difference ambiguity are unknown, and the rest are known quantities.

The matrix of equation (5) is expressed as follows:

Bb+W=0 (6)

among them,

_{_{W = (w 1, w 2}} , w 3) T,

i=1, 2, 3.

Available from formula (6)

b=-B ^-1 W (7)

Assuming the baseline length is d, according to equation (7)

d ² =b ^T b=W ^T (BB ^T ) ^-1 W=W ^T QW Equation (8)

Where Q is a third-order symmetric positive definite matrix. Do Jorishsky decomposition on matrix Q, ie Q=L ^T L, substituting equation (8)

d ² =W ^T L ^T LW=(LW) ^T (LW) Equation (9)

L is the lower triangular matrix and can be expressed as

Formula (10)

definition

l ₁ =l ₁₁ w ₁ ,l ₂ =l ₂₁ w ₁ +l ₂₂ w ₂ ,l ₃ =l ₃₁ w ₁ +l ₃₂ w ₂ +l ₃₃ w ₃ (11)

Substitute (9)

Formula (12)

Constrained by baseline length

Formula (13)

Can be derived from the above formula

-d _max <l ₁ <d _max (14)

Formula (15)

Available from formula (14)

Formula (16)

Of formula (16) is a double-difference ambiguity search range N _1. After N ₁ selects a specific value, w ₁ and l ₁ are determined, and the search range of N ₂ is obtained according to formula (12).

Formula (17)

After both N ₁ and N ₂ are determined, w ₁ and w _{2 are} also determined, thereby calculating the values of l ₁ and l ₂ . According to formula (13)

Equation (18)

If

Then the search range of N ₃ includes two intervals

Formula (19)

If

Then the search range of N ₃ is

Formula (20)

Thus, the entire circumference ambiguity N _{3 is obtained} .

This method is effective at short baselines, and the whole-circumference ambiguity is limited to the range of baseline limits, which is suitable for UAV attitude measurement.

Further, to obtain ambiguity after N _3, to calculate the baseline vector B, excluding incompatible with solutions baseline length requirement, would be consistent with the observation equation length requirements may baseline vector solution substituting redundant star, substituting redundant star carrier The phase double-difference equation is used to calculate the full-circumference ambiguity of the redundant star immediately. Then, based on the full-circumference ambiguity of all satellites, the sum of squared residuals of the carrier-phase double-difference equation is calculated, and the sum of the smallest residuals is summed among all possible solutions. The corresponding whole-circumference ambiguity is taken as the solution to be determined. When multiple epochs obtain the same to-be-determined solution, it can be considered that the to-be-determined solution is a fixed solution.

Further, the baseline vector includes: a first baseline vector from a first antenna to a second antenna of the three antennas, and a second baseline vector of the first antenna to the third antenna; Calculating the attitude data of the drone according to the vector includes: calculating a heading angle and a pitch angle of the drone according to the first baseline vector; calculating a roll angle of the drone according to the second baseline vector . The following examples illustrate:

As shown in Figures 3 and 4, the solution uses three GPS antennas, mounted on the nose, tail and wing (or arm), where the center of the drone is at the midpoint of antenna 1 and antenna 2. The azimuth angle of the antenna 1 and the antenna 2 is the yaw angle of the drone, and the tilt angle is the pitch angle. The tilt angle of the antenna 3 to the center is the roll angle. If the coordinates of the two points are known, the azimuth and tilt angle can be solved according to the formula. Therefore, it is only necessary to have the position of the antenna 1 and calculate the exact vector of the antenna 2, the antenna 3 and the center relative to the antenna 1 to calculate an accurate Gesture information.

As shown in FIG. 4, the receiver receives the antenna signal, calculates the antenna position, and transmits the position information and the raw observation to the attitude solving processor. The attitude calculation processor calculates the antenna 1 to antenna 2 vector, the antenna 1 to the antenna 3 vector based on the coordinates of the antenna 1, and finally calculates the heading angle, the elevation angle and the roll angle of the drone by the formula. The attitude information can be used as the measurement information of the optimal estimation algorithm such as Kalman filter, and is combined with other attitude data such as inertial navigation to obtain the optimal estimation value of the attitude, and further improve the attitude estimation accuracy. The calculated flight control data is transmitted to the flight control system.

It should be noted that in addition to GPS, the current global satellite navigation system includes Russia's GLONASS, China's Beidou, and Europe's GALILEO. In addition to using GPS to implement this solution, other satellite navigation systems can be used, or multiple satellite navigation systems can be used to implement the solution.

It can be seen from the above that the embodiment of the present invention provides an implementation scheme of satellite navigation and attitude measurement on a drone, which improves the accuracy of flight attitude estimation, solves the magnetic field interference problem of the compass, and can be used for flight control of the drone. Providing more reliable attitude data; the embodiment of the present invention uses a least squares search method with a baseline distance constraint to solve the whole-circumference ambiguity and carrier phase double difference equation, which is suitable for single-frequency and dual-frequency receivers, when using a single-frequency receiver It can effectively reduce the cost of the product, and at the same time simplify the calculation method and reduce the computational complexity.

In order to better implement the above solution of the embodiments of the present invention, related devices for cooperating to implement the above solutions are also provided below.

Referring to FIG. 5, a second embodiment of the present invention provides a satellite navigation device for testing a posture of a drone, and the drone is provided with three antennas that are not on the same straight line. It should be noted that the number of antennas installed on the UAV can also be more than three, and more than three antennas can be used as redundancy, and can also participate in the attitude calculation processing. The device can include:

An obtaining module 510, configured to obtain an original observation of a satellite signal, an ephemeris, and a position of an antenna, where the raw observation includes a carrier observation value and a pseudorange observation value;

The calculation module 520 is configured to obtain a unit vector between the antenna and the satellite according to the position of the ephemeris and the antenna; the carrier double difference is obtained based on the carrier observation, and the unit vector double difference of the antenna to the satellite is obtained based on the position of the ephemeris and the antenna ; based on carrier double difference, antenna-to-satellite unit vector double difference and baseline length between two antennas to obtain full-circumference ambiguity; based on the whole-circumference ambiguity, antenna-to-satellite unit vector double difference The carrier double difference results in a baseline vector between the three antennas; the attitude angle is derived based on the position of the antenna and the baseline vector between the three antennas.

In some embodiments of the present invention, the calculating module 520 includes:

The ambiguity calculation unit is configured to solve the whole-circumference ambiguity by a least squares search method using a baseline distance constraint.

In some embodiments of the present invention, the ambiguity calculation unit is specifically configured to:

The tracked satellites are divided into a main star and a redundant star, the main star includes four, and one of the four main stars serves as a reference star, and the reference star has the highest elevation angle;

Constructing a carrier double difference equation of the reference star and other main stars, determining a double difference ambiguity search range of the main star carrier double difference equation, and calculating a possible solution of the baseline vector;

Constructing a carrier double difference equation of the reference star and the redundant star, and substituting the baseline vector possible solution into a redundant star carrier double difference equation to determine a double difference ambiguity of the redundant star;

The full-circumference ambiguity is determined based on the double-difference ambiguity of all satellites.

In some embodiments of the present invention, the ambiguity calculation unit is further configured to:

Substituting the double-difference ambiguity of all satellites into the medium-carrier double-difference equation, calculating the sum of squared residuals of the equations, taking the whole-circumference ambiguity corresponding to the sum of squares of the smallest residuals as the to-be-determined solution in all possible solutions, when multiple calendars The element obtains the same pending solution, confirming that the to-be-determined solution is a fixed solution.

In some embodiments of the present invention, the baseline vector includes: a first baseline vector from a first antenna to a second antenna of the three antennas, and a second baseline vector of the first antenna to the third antenna; The calculation module 520 includes: an attitude data calculation unit, configured to calculate a heading angle and a pitch angle of the drone based on the positions of the first antenna and the second antenna and the first baseline vector; The position of the first antenna and the third antenna and the second baseline vector calculate the roll angle of the drone.

In some embodiments of the invention, the apparatus further includes:

The fusion module 530 is configured to fuse the obtained attitude angle and the inertial navigation data to obtain an optimized estimation of the attitude angle for performing the attitude control of the drone.

In some embodiments of the present invention, the obtaining module 510 is configured to receive a satellite signal through the antenna by using a single frequency receiver.

It is to be understood that the functions of the various functional modules of the satellite navigation device in the embodiments of the present invention may be specifically implemented according to the method in the foregoing method embodiments. For the specific implementation process, refer to the related description in the foregoing method embodiments, and details are not described herein again.

It can be seen that, in some feasible implementation manners of the embodiments of the present invention, a satellite navigation apparatus is provided, which is based on data such as carrier double difference obtained by satellite signals, and solves the whole-circumference ambiguity and the baseline between the antennas. The vector, the technical solution for calculating the attitude angle from the baseline vector, achieves the following technical effects:

Second, by constructing the carrier phase double-difference equation positioning, the least squares search method based on the baseline distance constraint is used to solve the whole-circumference ambiguity. On the one hand, it is suitable for the single-frequency receiver, compared with the dual-frequency receiver used in the prior art. Reduced costs; on the other hand, simplified calculation methods and reduced computational complexity.

A fourth embodiment of the present invention further provides a drone, the drone comprising:

a body, at least three antennas disposed on the body and not on the same straight line, the at least three antennas being respectively connected to at least three receivers, the at least three receivers being connected to a flight control system, The flight control system is used to:

It is easy to understand that the drone can also include a power system and an electrical system.

In some embodiments of the invention, the drone is a fixed wing drone, a helicopter drone, or an unmanned vehicle.

In some embodiments of the present invention, as shown in FIG. 3, the airframe includes a central portion, an arm on both sides of the central portion, a nose and a tail; three antennas are respectively disposed on the nose and the machine Tail and one arm.

In some embodiments of the invention, the flight control system is also used to minimize the baseline distance constraint The two-square search method solves the whole-circumference ambiguity.

In some embodiments of the present invention, the flight control system is further specifically configured to:

In some embodiments of the present invention, the flight control system is further configured to: substitute the double-difference ambiguity of all satellites into the medium-carrier double-difference equation, calculate the sum of squared residuals of the equation, and minimize the residual in all possible solutions. The whole-circumference ambiguity corresponding to the difference square sum is taken as the solution to be determined. When multiple epochs obtain the same to-be-determined solution, it is confirmed that the to-be-determined solution is a fixed solution.

In some embodiments of the present invention, the baseline vector includes: a first baseline vector from a first antenna to a second antenna of the three antennas, and a second baseline vector of the first antenna to the third antenna; The flight control system is further configured to calculate a heading angle and a pitch angle of the drone based on the positions of the first antenna and the second antenna and the first baseline vector; based on the first antenna and the third The position of the antenna and the second baseline vector calculate the roll angle of the drone.

In some embodiments of the invention, the flight control system is further configured to receive satellite signals through the antenna using a single frequency receiver.

In some embodiments of the present invention, the flight control system is configured to fuse the derived attitude angle and the inertial navigation data to obtain an optimized estimate of the attitude angle for performing the attitude control of the drone.

It can be seen that, in some feasible implementation manners of the embodiments of the present invention, a drone is provided, and the drone achieves the following technical effects:

The fifth embodiment of the present invention further provides a processor for testing the posture of the drone, wherein the drone is provided with three antennas not on the same straight line, and the processor can perform the following steps:

In some embodiments of the invention, the processor is further configured to: solve the whole-circumference ambiguity by a least squares search method with a baseline distance constraint.

In some embodiments of the invention, the processor is further configured to:

Substituting the double-difference ambiguity of all satellites into the medium-carrier double-difference equation, calculating the sum of the residuals of the equations, and taking the whole-circumference ambiguity corresponding to the sum of the squares of the smallest residuals as the to-be-determined solution in all possible solutions, when multiple The epoch obtains the same pending solution, confirming that the pending solution is a fixed solution.

In some embodiments of the present invention, the baseline vector includes: a first baseline vector from a first antenna to a second antenna of the three antennas, and a second baseline vector of the first antenna to the third antenna; The processor is further configured to: calculate a heading angle and a pitch angle of the drone based on the positions of the first antenna and the second antenna and the first baseline vector; based on the first antenna and the third The position of the antenna and the second baseline vector calculate the roll angle of the drone.

The processor is further configured to receive a satellite signal through the antenna using a single frequency receiver.

The processor is further configured to: fuse the obtained attitude angle and the inertial navigation data to obtain an optimized estimation of the attitude angle, and perform the attitude control of the drone.

A sixth embodiment of the present invention further provides a computer storage medium, wherein the computer storage medium can store a program, and the program includes some or all of the steps of the satellite navigation attitude measurement method described in the foregoing method embodiments.

In the above embodiments, the descriptions of the various embodiments are different, and the parts that are not described in detail in a certain embodiment can be referred to the related description of other embodiments.

It should be noted that, for the foregoing method embodiments, for the sake of brevity, they are all described as a series of action combinations, but those skilled in the art should understand that the present invention is not limited by the described action sequence, because In accordance with the present invention, certain steps may be performed in other sequences or concurrently. In addition, those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

A person skilled in the art may understand that all or part of the various steps of the foregoing embodiments may be performed by a program to instruct related hardware. The program may be stored in a computer readable storage medium, and the storage medium may include: ROM, RAM, disk or CD.

The satellite navigation attitude determining method and device and the drone provided by the embodiments of the present invention are described in detail. The principles and implementation manners of the present invention are described in the following. The description of the above embodiments is only used for To help understand the method of the present invention and its core idea; at the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in specific embodiments and application scopes. It should not be construed as limiting the invention.

Claims

A satellite navigation attitude measuring method, characterized in that it is used for testing a posture of a drone, and the drone is provided with three antennas not on the same straight line, and the method includes:

Obtaining raw observations of satellite signals, ephemeris, and locations of antennas, the raw observations including carrier observations and pseudorange observations;

Deriving the unit vector between the antenna and the satellite according to the position of the ephemeris and the antenna;

Based on the carrier observation, the carrier double difference is obtained, and the unit vector double difference of the antenna to the satellite is obtained based on the position of the ephemeris and the antenna;

The whole-circumference ambiguity is obtained based on the carrier double difference, the antenna-to-satellite unit vector double difference, and the baseline length between the two antennas;

Determining a baseline vector between the three antennas based on the whole-circumference ambiguity, antenna-to-satellite unit vector double difference, and carrier double difference;

The attitude angle is derived based on the position of the antenna and the baseline vector between the three antennas.
The method according to claim 1, wherein said quadratic difference based on carrier double difference, antenna to satellite unit vector difference, and baseline length between two antennas comprises:

The whole-circumference ambiguity is solved using a least squares search method with baseline distance constraints.
The method according to claim 2, wherein said solving the whole-circumference ambiguity by using a least squares search method with a baseline distance constraint comprises:

The tracked satellites are divided into a main star and a redundant star, the main star includes four, and one of the four main stars serves as a reference star, and the reference star has the highest elevation angle;

Constructing a carrier double difference equation of the reference star and other main stars, determining a double difference ambiguity search range of the main star carrier double difference equation, and calculating a possible solution of the baseline vector;

Constructing a carrier double difference equation of the reference star and the redundant star, and substituting the baseline vector possible solution into a redundant star carrier double difference equation to determine a double difference ambiguity of the redundant star;

The full-circumference ambiguity is determined based on the double-difference ambiguity of all satellites.
The method according to claim 3, wherein said determining the full-circumference ambiguity according to the double-difference ambiguity of all satellites comprises:

Substituting the double-difference ambiguity of all satellites into the medium-carrier double-difference equation to calculate the residual square of the equation And, in all possible solutions, the whole-circumference ambiguity corresponding to the sum of squares of the minimum residuals is taken as a solution to be determined. When multiple epochs obtain the same to-be-determined solution, it is confirmed that the to-be-determined solution is a fixed solution.
The method according to any one of claims 1 to 4, wherein the baseline vector comprises: a first baseline vector from a first antenna to a second antenna of the three antennas, and a first antenna to a first a second baseline vector of three antennas;

The determining the attitude angle based on the position of the antenna and the baseline vector between the three antennas includes:

Calculating a heading angle and a pitch angle of the drone based on positions of the first antenna and the second antenna and the first baseline vector; based on positions of the first antenna and the third antenna, and the second The baseline vector calculates the roll angle of the drone.
The method according to any one of claims 1 to 4, wherein before the obtaining the original observation of receiving the satellite signal, the method further comprises:

A satellite signal is received through the antenna using a single frequency receiver.
The method according to any one of claims 1 to 4, further comprising:

The obtained attitude angle and the inertial navigation data are fused to obtain an optimized estimation of the attitude angle for the attitude control of the drone.
A satellite navigation device for testing a posture of a drone, wherein the drone is provided with three antennas not on the same straight line, the device comprising:

An acquisition module, configured to obtain a raw observation of a satellite signal, an ephemeris, and a position of an antenna, the original observation including a carrier observation and a pseudorange observation;

a calculation module for deriving a unit vector between the antenna and the satellite according to the position of the ephemeris and the antenna; deriving a carrier double difference based on the carrier observation, and obtaining a unit vector double difference of the antenna to the satellite based on the position of the ephemeris and the antenna; The whole-circumference ambiguity is obtained based on the carrier double difference, the antenna-to-satellite unit vector double difference, and the baseline length between the two antennas; based on the whole-circumference ambiguity, the antenna-to-satellite unit vector double difference, and the carrier double difference A baseline vector between the three antennas; the attitude angle is derived based on the position of the antenna and the baseline vector between the three antennas.
The device according to claim 8, wherein the calculation module comprises:

The ambiguity calculation unit is configured to solve the whole-circumference ambiguity by a least squares search method using a baseline distance constraint.
The device of claim 9 wherein:

The ambiguity calculation unit is specifically configured to:

The tracked satellites are divided into a main star and a redundant star, the main star includes four, and one of the four main stars serves as a reference star, and the reference star has the highest elevation angle;

Constructing a carrier double difference equation of the reference star and other main stars, determining a double difference ambiguity search range of the main star carrier double difference equation, and calculating a possible solution of the baseline vector;

Constructing a carrier double difference equation of the reference star and the redundant star, and substituting the baseline vector possible solution into a redundant star carrier double difference equation to determine a double difference ambiguity of the redundant star;

The full-circumference ambiguity is determined based on the double-difference ambiguity of all satellites.
The device of claim 10 wherein:

The ambiguity calculation unit is further configured to: substitute the double-difference ambiguity of all satellites into the medium-carrier double-difference equation, calculate a sum of squares of residuals of the equation, and blur the entire week corresponding to the sum of squares of the smallest residuals among all possible solutions. The degree is taken as the solution to be determined. When multiple epochs obtain the same solution to be determined, it is confirmed that the solution to be determined is a fixed solution.
The apparatus according to any one of claims 8 to 11, wherein the baseline vector comprises: a first baseline vector from a first antenna to a second antenna of the three antennas, and a first antenna to a second baseline vector of three antennas; the calculation module includes:

a posture data calculation unit, configured to calculate a heading angle and a pitch angle of the drone based on the positions of the first antenna and the second antenna and the first baseline vector; based on the first antenna and the third antenna The position of the second baseline vector and the roll angle of the drone are calculated.
A device according to any one of claims 8 to 11, wherein

The acquiring module is configured to receive a satellite signal through the antenna by using a single frequency receiver.
The device according to any one of claims 8 to 11, further comprising:

The fusion module is used to fuse the obtained attitude angle and the inertial navigation data to obtain an optimized estimation of the attitude angle for performing the attitude control of the drone.
A drone, characterized in that it comprises:

a body, at least three antennas disposed on the body and not on the same straight line, the at least three antennas being respectively connected to at least three receivers, the at least three receivers being connected to a flight control system, The flight control system is used to:

Obtaining the original observation of the satellite signal, the ephemeris, and the position of the antenna through the at least three receivers and the at least three antennas, the raw observations including carrier observations and pseudorange observations; according to ephemeris and antennas The position derives the unit vector between the antenna and the satellite; based on the carrier observation, the carrier double difference is obtained, and the unit vector double difference of the antenna to the satellite is obtained based on the position of the ephemeris and the antenna; the unit vector based on the carrier double difference and the antenna to the satellite Double-difference and baseline length between two antennas to obtain full-circumference ambiguity; base vector between three antennas based on the whole-circumference ambiguity, antenna-to-satellite unit vector double difference, and carrier double difference; The position and the baseline vector between the three antennas yield the attitude angle.
The drone according to claim 15, wherein

The fuselage includes a central portion, an arm on both sides of the central portion, a nose and a tail;

Three antennas are respectively disposed at the head and the tail and one side of the arm.
The drone according to claim 15, wherein

The drone is a fixed-wing drone, a helicopter drone, or an unmanned vehicle.
The drone according to claim 15, wherein the flight control system is further configured to solve the full-circumference ambiguity by a least squares search method using a baseline distance constraint.
The drone according to claim 18, characterized in that

The flight control system is also specifically used to:

The tracked satellites are divided into a main star and a redundant star, the main star includes four, and one of the four main stars serves as a reference star, and the reference star has the highest elevation angle;

Constructing a carrier double difference equation of the reference star and other main stars, determining a double difference ambiguity search range of the main star carrier double difference equation, and calculating a possible solution of the baseline vector;

Constructing a carrier double difference equation of the reference star and the redundant star, and substituting the baseline vector possible solution into a redundant star carrier double difference equation to determine a double difference ambiguity of the redundant star;

The full-circumference ambiguity is determined based on the double-difference ambiguity of all satellites.
The drone according to claim 19, characterized in that

The flight control system is further configured to: substitute the double-difference ambiguity of all satellites into the medium-carrier double-difference equation, calculate the sum of the residuals of the equations, and sum the squared ambiguities corresponding to the sum of the smallest residuals in all possible solutions. Take the solution to be determined. When multiple epochs obtain the same pending solution, confirm that the pending solution is a fixed solution.
A drone according to any one of claims 15 to 20, wherein said baseline vector The method includes: a first baseline vector from a first antenna to a second antenna of the three antennas, and a second baseline vector of the first antenna to the third antenna; the flight control system is further configured to be based on the first Calculating a heading angle and a pitch angle of the drone by determining a position of the antenna and the second antenna and the first baseline vector; calculating a position based on the positions of the first antenna and the third antenna and the second baseline vector The roll angle of the drone.
A drone according to any one of claims 15 to 20, characterized in that

The flight control system is further configured to receive satellite signals through the antenna using a single frequency receiver.
The unmanned aerial vehicle according to any one of claims 15 to 20, wherein the flight control system is configured to fuse the obtained attitude angle and the inertial navigation data to obtain an optimized estimation of the attitude angle for performing no Man-machine attitude control.
The drone according to claim 23, wherein said drone further comprises an inertial measurement device, said inertial navigation data being measured by said inertial measurement device.