CN115164878A - GNSS/INS combined navigation method, equipment and storage medium - Google Patents
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- G—PHYSICS
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- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
- G01C21/10—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration
- G01C21/12—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning
- G01C21/16—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation
- G01C21/165—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation combined with non-inertial navigation instruments
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
- G01C21/20—Instruments for performing navigational calculations
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/13—Receivers
- G01S19/35—Constructional details or hardware or software details of the signal processing chain
- G01S19/37—Hardware or software details of the signal processing chain
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
- G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/40—Correcting position, velocity or attitude
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
- G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/42—Determining position
- G01S19/45—Determining position by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement
- G01S19/47—Determining position by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
- G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/42—Determining position
- G01S19/48—Determining position by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
- G01S19/49—Determining position by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system whereby the further system is an inertial position system, e.g. loosely-coupled
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Abstract
The invention discloses a GNSS/INS integrated navigation method, equipment and a storage medium, which relate to the technical field of satellite navigation, wherein the method comprises the following steps: acquiring GNSS observation data, and performing quality screening on the GNSS observation data based on inertial navigation recursion data, wherein the quality screening comprises gross error elimination and cycle slip repair; judging whether the observation condition of the current time period reaches the standard or not, if so, switching the navigation mode into a loose combination mode, and correcting inertial navigation according to the error estimation quantity between the observation data after quality screening and the recursive data of the inertial navigation in the loose combination mode; otherwise, switching the navigation mode into a tightly combined mode, combining inertial navigation recursion data to assist ambiguity fixing and obtain a fixed phase observation value, and performing inertial navigation correction according to an error estimator between the fixed phase observation value and the inertial navigation recursion data. The invention can realize the correct and effective switching of the elasticity combination mode, overcomes the defects of the operation of the independent mode and achieves the effect of maintaining the precision of the navigation system in any observation environment.
Description
Technical Field
The invention relates to the technical field of satellite navigation, in particular to a GNSS/INS combined navigation method, GNSS/INS combined navigation equipment and a storage medium.
Background
There are three combined modes of GNSS/INS integrated navigation: loose combination, tight combination and super tight combination; the three combinations are respectively characterized in that: the loose combination belongs to the fusion of a result layer, in a loose combination system, GNSS and inertial navigation are not interfered with each other, the influence of the working abnormity of a single system on the whole system can be effectively isolated, the system is stable and is not easy to collapse or disperse; in a tight combination system, high-precision position information obtained by inertial navigation recursion is utilized to improve the strength of an observation model, and even when the observation condition is poor, the fuzzy degree can be assisted to be fixed, so that a higher-precision fixed solution can be obtained. The ultra-tight combination is used for assisting GNSS signal capture and tracking on a hardware level by using an inertial navigation recursion result, and belongs to the combination of the hardware level.
The loose combination and the tight combination have the advantages and the disadvantages, the subsystems of the loose combination do not interfere with each other, the work is stable, the calculation complexity is small, but in a severe observation environment, the GNSS may have the situation that the ambiguity is fixed wrongly or even can not be fixed, so that the accumulation of inertial navigation errors can not be controlled, and the system state is diverged; in a severe observation environment, when ambiguity fixing can be assisted by high-precision position recursion information or the position recursion information cannot be fixed, the increase of an inertial navigation error is limited by using an available phase observation value and a pseudo range observation value, so that the system precision is maintained. When the observation condition is continuously good or is temporarily poor, the precision of the two combination modes is basically equivalent, and an tight combination which consumes more computing resources is not needed to be used, and when the observation condition is poor, the tight combination is needed to be started to maintain the system precision. However, the existing navigation system can only be operated in any fixed combination mode, and cannot solve the above mentioned disadvantages.
Disclosure of Invention
In order to overcome the disadvantages of the prior art, an object of the present invention is to provide a GNSS/INS combined navigation method, which applies a tight combination to a same system, and makes full use of the advantages of the tight combination to overcome the above disadvantages and maintain the accuracy of the system.
Another object of the present invention is to provide an electronic device.
It is a further object of the present invention to provide a storage medium.
One of the purposes of the invention is realized by adopting the following technical scheme:
a GNSS/INS integrated navigation method comprises the following steps:
acquiring GNSS observation data, and performing quality screening on the GNSS observation data based on inertial navigation recursion data, wherein the quality screening comprises gross error elimination and cycle slip repair;
judging whether the observation condition of the current time period reaches the standard or not, if so, switching the navigation mode into a loose combination mode, and correcting inertial navigation according to the error estimation quantity between the observation data after quality screening and the recursive data of the inertial navigation in the loose combination mode; otherwise, switching the navigation mode into a tight combination mode, combining inertial navigation recursive data to assist ambiguity fixing and obtain a fixed phase observation value, and performing inertial navigation correction according to an error estimator between the fixed phase observation value and inertial navigation speculative data.
Further, the method for acquiring the inertial navigation recursion data comprises the following steps:
acquiring inertial navigation data of the INS inertial navigation system at the current moment, and deducing inertial navigation recursion data of the next moment in a current navigation coordinate system through mechanical arrangement, wherein the inertial navigation recursion data comprise inertial navigation recursion position, velocity and attitude information.
Further, the quality screening method comprises the following steps:
performing gross error detection on the GNSS observation data, and calculating the gross error of an observation value by using the inertial navigation recursive data;
and judging whether the gross error of the observed value exceeds a threshold value, if so, rejecting the observed value, detecting the cycle slip of the observed value which completes the gross error detection and is not rejected, and recovering the cycle slip.
Further, the method for judging whether the observation condition of the current time period reaches the standard or not comprises the following steps:
and comparing the first risk value which is misjudged to be that the observation condition reaches the standard with the second risk value which is misjudged to be that the observation condition does not reach the standard, and if the first risk value is smaller than the second risk value, judging that the observation condition in the current time period reaches the standard.
Further, the first risk value and the second risk value are calculated by:
the first risk value R 1 ＝λ 12 ·(3-P 1 (ns)-P 2 (rateOut)-P 3 (rateCS))；
The second risk value R 2 ＝λ 21 ·(P 1 (ns)+P 2 (rateOut)+P 3 (rateCS))；
Wherein λ is 12 Misjudgment risk coefficient for misjudging the observation condition which does not reach the standard as the observation condition which reaches the standard;
λ 21 a misjudgment risk coefficient for misjudging the standard observation condition as the substandard observation condition;
P 1 (ns) is the probability that the observation condition reaches the standard when the number of available satellites is ns;
P 2 (rateOut) is the probability that the observation condition reaches the standard when the gross error ratio is rateOut;
P 3 (rateCS) is the probability that the observation condition reaches the standard when the cycle slip ratio is rateCS.
Further, the method for correcting inertial navigation in the loose combination mode comprises the following steps:
inputting the observation data after the quality screening into a GNSS estimator to obtain the estimation quantity of the position and the speed, and inputting the estimation quantity as a measurement value into a loose combination estimator;
inputting the position, speed and attitude information of the inertial navigation recursion data as estimated values into a loose combination estimator;
and carrying out error compensation on inertial navigation according to the error estimator output by the loose combination estimator.
Further, the method for fixing the ambiguity in the close-coupled mode is:
using the inertial navigation recursion position as a measurement value, and adding the measurement value into a measurement equation by combining a pseudo-range observation value and a phase observation value to calculate a floating solution of the ambiguity;
carrying out descending correlation operation on the ambiguities, then sorting the ambiguities according to the sequence of the variances from large to small, searching the ambiguities and carrying out ratio test, if the ambiguities pass the ratio test, determining that the ambiguities are successfully fixed, constructing an observed value by using the ambiguities fixed as integers, adding the fixed phase observed value into a tight combination estimator, outputting inertial navigation error estimation by the tight combination estimator, and feeding back the inertial navigation error estimation to an inertial navigation system for error compensation; and if the satellite number does not pass the ratio test, rejecting the satellite with the largest variance, and carrying out ambiguity search and ratio test again until the satellite number is less than a preset value or the ratio test is passed.
Further, if the ambiguity always fails in the process of fixing, the floating-point phase observation value and the pseudorange observation value are input into the close-combination estimator, and the close-combination estimator outputs inertial navigation error estimation which is fed back to the inertial navigation system for error compensation.
The second purpose of the invention is realized by adopting the following technical scheme:
an electronic device comprising a processor, a memory and a computer program stored on the memory and executable on the processor, the processor implementing the GNSS/INS combined navigation method as described above when executing the computer program.
The third purpose of the invention is realized by adopting the following technical scheme:
a computer-readable storage medium, having stored thereon a computer program which, when executed, implements a GNSS/INS combined navigation method as described above.
Compared with the prior art, the invention has the beneficial effects that:
the method applies the loose combination and the tight combination to the same navigation system, combines the single epoch data quality judgment and the interval comprehensive judgment, ensures the navigation system mode to be correctly and effectively switched, switches to the loose combination mode when the observation condition is good, and switches to the tight combination mode when the observation condition is relatively poor, fully utilizes the advantages of the tight combination, overcomes the defects existing in the operation of the single mode, and can maintain the precision of the navigation system in any observation environment.
Drawings
FIG. 1 is a flowchart illustrating a GNSS/INS integrated navigation method according to the present invention.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and the detailed description, and it should be noted that any combination of the embodiments or technical features described below can be used to form a new embodiment without conflict.
Example one
The embodiment provides a GNSS/INS combined navigation method, which applies at least two combined modes to the same navigation system, and combines the advantages of the combined modes in a mode switching manner to overcome the problem of navigation accuracy in different observation environments, thereby bringing the combined effect into full play.
In this embodiment, the slack combination mode and the tight combination mode are applied to the same system, and the switching of the slack combination mode is performed; in some embodiments, the loosely combined switching mode may also be replaced by loosely combined \ inertially assisted GNSS switching, or switching of similar loosely combined with other GNSS/INS combinations.
Referring to fig. 1, the present embodiment takes the mode of the slack combination switching as an example to describe the navigation correction step:
step S1: acquiring GNSS observation data, and performing quality screening on the GNSS observation data based on inertial navigation recursion data, wherein the quality screening comprises gross error elimination and cycle slip repair;
step S2: judging whether the observation condition of the current time period reaches the standard or not, if so, switching the navigation mode into a loose combination mode, and correcting inertial navigation according to the error estimation quantity between the observation data after quality screening and the recursive data of the inertial navigation in the loose combination mode; otherwise, switching the navigation mode into a tightly combined mode, combining inertial navigation recursion data to assist ambiguity fixing and obtain a fixed phase observation value, and performing inertial navigation correction according to an error estimator between the fixed phase observation value and the inertial navigation recursion data.
The GNSS observation data are satellite observation values acquired through a GNSS receiver and mainly comprise pseudo-range observation values, carrier phase observation values and the like. Meanwhile, inertial navigation data is acquired from an inertial navigation system (INS, hereinafter referred to as inertial navigation); the basic working principle of the inertial navigation system is based on Newton's law of mechanics, and inertial navigation data such as velocity, yaw angle and position in a navigation coordinate system can be obtained by measuring the acceleration of a carrier in an inertial reference system, integrating the acceleration with time and transforming the acceleration into the navigation coordinate system.
In the embodiment, when the GNSS observation data are subjected to quality screening, an inertial navigation recursion position is required to be utilized to assist in GNSS data gross error detection and cycle slip detection and repair; the method for acquiring the recursive position of inertial navigation is to use inertial navigation data to perform mechanical layout, and specifically:
in order to ensure the consistency of the system, a local and local fixed system is selected as a navigation coordinate system of the navigation system in a unified way; and unifying the definition of the error as the true value minus the calculated value to be the error. In this embodiment, after obtaining the inertial navigation data of the inertial navigation system at the current time (k time), the next time is obtained from the current time (k time) through mechanical arrangementPosition v at time (k + 1) k+1 Velocity p k+1 Posture information
And (3) equal inertial navigation recurrence data, wherein the mechanical arrangement process is as the formula (1):
in the formula, v cor For the correction of Coriolis force, v sf The specific force velocity increment, dt is the inertial data time interval,
the superscript r of (a) denotes the navigation system, i.e. the earth-centered earth-fixed system, and the subscript b denotes the carrier coordinate system.
The rotation vector is obtained from the rotation vector opposite to the direction of the rotation of the earth,
from the corrected angle increment.
After the inertial navigation recursion position is obtained through calculation, the inertial navigation recursion position is used for assisting GNSS data gross error detection and cycle slip detection and repair, and the method specifically comprises the following steps:
performing gross error detection on the GNSS observation data, and respectively calculating gross error detection quantities of pseudo-range observation values and phase observation values by using the inertial navigation recursion data;
and judging whether the gross error detection quantity of the pseudo-range observation value and the phase observation value exceeds a threshold value, if so, judging that the gross error is detected, and determining that the observation value is invalid. And after the gross error detection is finished, the carrier observed values which are not removed enter a cycle slip detection link, the cycle slip is detected, and the cycle slip is repaired.
In the course of gross error detection, for pseudo-range observed values, there are:
in the above formula, P is a pseudo-range observed value, Φ is a phase observed value, the superscript G represents GNSS, and the superscript I represents inertial navigation. Delta is an inter-satellite single difference operator, and relevant errors of the mobile station, such as multipath errors, clock difference and the like, are eliminated or weakened through the inter-satellite single difference;
the method is an inter-station single difference operator, and satellite related errors such as ionosphere errors, troposphere errors, ephemeris errors, satellite clock errors and the like are eliminated or weakened through the inter-station single difference. ρ is the distance to the earth calculated from the inertial navigation position.
Calculating the gross error detection quantity of the pseudo-range observed value by the formula (5)Equation (6) obtains the gross error detection amount of the phase observed value. Wherein, T P And T Φ The threshold value of (c) is set as a formula (7), and k is given according to a pseudo range code and carrier wave precision corresponding to reference according to experience; e is a direction cosine vector of the direction,
is the average ratio of e between epochs, P v,k+1/2 Is a covariance matrix of inertial navigation velocity at the intermediate time, P ψ,k+1/2 And the inertial navigation misalignment angle covariance matrix at the intermediate moment.
When T is P And T Φ When the difference exceeds the threshold, the coarse difference is judged to be detected, and the observed value is considered to be invalid. And after the gross error detection is finished, the carrier observed values which are not removed enter a cycle slip detection link, and cycle slip is detected and repaired.
The method comprises the steps of performing GNSS data quality screening to obtain refined observation data after gross error and cycle slip are removed and repaired, simultaneously obtaining detected gross error and cycle slip in the process of performing gross error detection and cycle slip detection, determining observation statistical information such as available satellite numbers and the like according to a used satellite system, inputting the observation statistical information into an epoch information sliding window, and calculating the average gross error ratio, the average cycle slip ratio and the average available satellite number of a current epoch by the system according to a weighted moving average method.
Then, judging whether the observation condition of the current time period reaches the standard or not by adopting minimum risk Bayes, namely determining the probability that the number of available satellites corresponds to the standard of the observation condition according to the used satellite system, and respectively determining probability functions of the gross error data and the cycle slip data which correspond to the standard of the observation condition according to the gross error data and the cycle slip data which are obtained by data statistics; the three probability functions are as follows, and can be modified according to the equipment and the environment:
a. when the number of available satellites is ns, the probability of good observation condition is P 1 (ns)；
b. When the gross error data ratio is rateOut, the probability of good observation condition is P 2 (rateOut)；
c. When the ratio of cycle slip data is rateCS, the probability of good observation condition is P 3 (rateCS)；
Determining misjudgment risk coefficient according to experience and use sceneIs [0 lambda ] 12 λ 21 0]Wherein λ is 12 In order to misjudge the condition that the observation condition does not reach the standard as the misjudgment risk coefficient that the observation condition reaches the standard, lambda 21 And the misjudgment is the misjudgment risk coefficient for misjudging the condition that the observation condition reaches the standard as the condition that the observation condition does not reach the standard.
Calculating a risk value according to the misjudgment risk coefficient:
R 1 ＝λ 12 ·(3-P 1 (ns)-P 2 (rateOut)-P 3 (rateCS))；
R 2 ＝λ 21 ·(P 1 (ns)+P 2 (rateOut)+P 3 (rateCS))；
wherein R is 1 For a first risk value, R, of which the observation condition has reached the standard 2 And judging the second risk value as a wrong second risk value that the observation condition does not reach the standard. If R is 1 <R 2 If the data quality in the time period is good, the observation condition can be judged to reach the standard, and at the moment, the loose combination mode is entered; otherwise, the tight combination mode is entered.
In some embodiments, the determination of the quality of the time period data may be performed by fisher determination, direct threshold setting, or other methods instead of the foregoing minimum bayesian method.
And under the loose combination mode, inputting the refined observation value obtained after the quality screening into a GNSS estimator to obtain position and speed estimators. And inputting the position and speed estimators into a loose combination estimator as measured values, inputting position, speed and attitude information in the inertial navigation recursion data into the loose combination estimator as estimated values, outputting error estimators by the loose combination estimator, and feeding the error estimators back to an inertial navigation system for error compensation.
The pine combination estimator can be a Kalman filter, and performs integrated navigation solution by using a pine combination observation equation formula (7):
in the formula, R IG To add a rodArm corrected inertial navigation position, V IG To add the inertial navigation speed corrected by the lever arm,
l b is a lever arm tied down by a carrier e In order to tie down the lever arm in the ground,
in the form of a vector of angular velocity,
is the earth rotation vector.
Under a tight combination mode, the inertial navigation recursion position is utilized to assist ambiguity fixing by a full combination method, namely the inertial navigation position is used as a measurement value, and the measurement value, a pseudo range observation value and a phase observation value are added into a measurement equation shown in a formula (8) together to calculate a floating solution of ambiguity, wherein a corresponding measurement noise array is shown in a formula (9):
in the above formula, A 1 When a dynamic model is adopted, the expression is shown as formula (10), and e is a cosine vector in the direction of the defense-ground distance. B is a coefficient matrix of the ambiguity parameters, and u is an ionospheric delay coefficient. A. The 2 The non-ambiguity coefficient matrix corresponding to the position observation value is expressed as formula (11).
A 1 ＝[e 0 0 u 0] (10)
A 2 ＝[I 0 0] (11)
The measurement equation formula (8) adopts an estimator to solve a plurality of floating solutions of the ambiguity, and because the correlation among the plurality of floating solutions of the ambiguity is strong, a decorrelation operation is required to be carried out before the ambiguity is fixed so as to weaken the correlation of the ambiguity. In the embodiment, a partial ambiguity fixing strategy is adopted for ambiguity fixing, namely after the GNSS integer ambiguity fixing algorithm (LAMBDA algorithm) is adopted for correlation reduction, the square differences are sorted from big to small, and ambiguity searching and ratio inspection are carried out; if the ratio test is passed and the fixed solution residual error chi-square test is passed, determining that the ambiguity is successfully fixed, and exiting the fixed part; otherwise, the satellite with the largest variance is removed, and a round of ambiguity search is performed again until the number of satellites is less than a preset value (in the embodiment, the preset value is 4) or the ratio test is passed. And if the ratio test is not passed, determining that the ambiguity fixing fails.
If the ambiguity is successfully fixed, an observation value is constructed by using the ambiguity fixed as an integer according to a formula (13), the fixed phase observation value is added into a close-combination estimator, a pseudo-range observation value is not used, the system state of the close-combination estimator only comprises an inertial navigation state at the moment, and an observation equation is shown as a formula (12);
in the formula (12), the inertial navigation states are X Ψ Misalignment angle, X v Speed error, X p Position error, X bg Gyro zero offset error and X ba The accelerometer has zero offset error.
Equation (13) represents a method for constructing a single-frequency single-phase observation, Δ N fix Is the fixed single-differenced ambiguity, λ is the corresponding carrier wavelength,
in order to delay the tropospheric delay,
is the ionospheric delay and u is the ionospheric delay coefficient.
If the fixing fails, inputting the floating-point phase observation value and the pseudo-range observation value into a close-combination estimator together, wherein the system state of the close-combination estimator comprises ambiguity, and an observation equation is as follows (14):
in formula (14): a. The 4 ＝[0 u]； (15)
Equation (17) represents a single pseudorange observation construction, and equation (17) differs from equation (14) in that the equations are substituted with floating ambiguities.
And finally, outputting inertial navigation error estimation by the close combination estimator, and feeding back the inertial navigation error estimation to an inertial navigation system for error compensation to finish inertial navigation correction.
For the case of fixing failure, the observation value of the satellite with the continuously fixed previous epoch is preferentially used, and when the number of the satellites is less than 4, the satellite is not screened and is not used completely. In equation (14), the updated covariance matrix of the last measurement is used for the ambiguity parameters, and if the mode is not entered (tight combination of fixed failure) last time, the covariance matrix of the non-ambiguity parameters is cleared; if the mode is entered last time, the non-ambiguity parameter covariance matrix is continuously used and updated, and the updating mode is as shown in formula (18):
in the above formula, in order to observe the mechanical arrangement accumulated state transition matrix between epochs, the calculation method is shown in formula (19):
F k+1,k ＝F k+1,j ·F j,j-1 L F 2,1 ·F 1,k 。 (19)
in the embodiment, two combinations are applied to the same system, and strict single epoch data quality judgment and interval comprehensive judgment are combined, so that the correct and effective mode switching is ensured, the advantages of the loose and tight combination are fully utilized, the defects mentioned above are overcome, and the combination effect is exerted to the maximum.
Example two
The embodiment provides an electronic device, which comprises a processor, a memory and a computer program stored on the memory and capable of running on the processor, wherein the processor implements the GNSS/INS combined navigation method in the first embodiment when executing the computer program; in addition, the present embodiment also provides a computer-readable storage medium, on which a computer program is stored, where the computer program is executed to implement the GNSS/INS combined navigation method.
The device and the storage medium in this embodiment are based on two aspects of the same inventive concept, and the method implementation process has been described in detail in the foregoing, so that those skilled in the art can clearly understand the structure and implementation process of the device and the storage medium in this embodiment according to the foregoing description, and for the sake of brevity of the description, details are not repeated here.
The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are within the protection scope of the present invention.
Claims (10)
1. A GNSS/INS integrated navigation method is characterized by comprising the following steps:
acquiring GNSS observation data, and performing quality screening on the GNSS observation data based on inertial navigation recursion data, wherein the quality screening comprises gross error elimination and cycle slip repair;
judging whether the observation condition of the current time period reaches the standard or not, if so, switching the navigation mode into a loose combination mode, and correcting inertial navigation according to the error estimation quantity between the observation data after quality screening and the recursive data of the inertial navigation in the loose combination mode; otherwise, switching the navigation mode into a tight combination mode, combining inertial navigation recursive data to assist ambiguity fixing and obtain a fixed phase observation value, and performing inertial navigation correction according to an error estimator between the fixed phase observation value and inertial navigation speculative data.
2. The GNSS/INS integrated navigation method of claim 1, wherein the method for obtaining the inertial navigation recursion data comprises:
acquiring inertial navigation data of an INS inertial navigation system at the current output moment, and pushing out inertial navigation recursive data of the next moment in a current navigation coordinate system through mechanical arrangement, wherein the inertial navigation recursive data comprises inertial navigation recursive position, velocity and attitude information.
3. The GNSS/INS integrated navigation method of claim 1, wherein the quality screening method comprises:
performing gross error detection on the GNSS observation data, and calculating the gross error of the observation value by using the inertial navigation recursion data;
and judging whether the gross error of the observed value exceeds a threshold value, if so, rejecting the observed value, detecting the cycle slip of the observed value which is detected by the gross error and is not rejected, and recovering the cycle slip.
4. The GNSS/INS integrated navigation method of claim 1, wherein the method for determining whether the observation conditions in the current time period are up to standard is:
and comparing the first risk value which is misjudged to be that the observation condition reaches the standard with the second risk value which is misjudged to be that the observation condition does not reach the standard, and if the first risk value is smaller than the second risk value, judging that the observation condition in the current time period reaches the standard.
5. The GNSS/INS combined navigation method of claim 4, wherein the first risk value and the second risk value are calculated by:
the first risk value R 1 ＝λ 12 ·(3-P 1 (ns)-P 2 (rateOut)-P 3 (rateCS))；
The second risk value R 2 ＝λ 21 ·(P 1 (ns)+P 2 (rateOut)+P 3 (rateCS))；
Wherein λ is 12 Misjudgment risk coefficients for misjudging the unqualified observation conditions into the qualified observation conditions;
λ 21 a misjudgment risk coefficient for misjudging the standard observation condition as the substandard observation condition;
P 1 (ns) is the probability that the observation condition reaches the standard when the number of available satellites is ns;
P 2 (rateOut) is the probability that the observation condition reaches the standard when the gross error ratio is rateOut;
P 3 (rateCS) is the probability that the observation condition reaches the standard when the cycle slip ratio is rateCS.
6. The GNSS/INS combined navigation method of claim 1, wherein the method for correcting inertial navigation in the loosely combined mode is:
inputting the observation data after the quality screening into a GNSS estimator to obtain the estimation quantity of the position and the speed, and inputting the estimation quantity as a measurement value into a loose combination estimator;
inputting the position, speed and attitude information of the inertial navigation recursion data as estimated values into a loose combination estimator;
and carrying out error compensation on inertial navigation according to the error estimator output by the loose combination estimator.
7. The GNSS/INS combined navigation method of claim 1, wherein the method for fixing the ambiguity in the tightly combined mode is:
using the inertial navigation recursion position as a measurement value, and adding the measurement value into a measurement equation by combining a pseudo-range observation value and a phase observation value to calculate a floating point solution of ambiguity;
carrying out descending correlation operation on the ambiguities, then sorting the ambiguities according to the sequence of the variances from large to small, searching the ambiguities and carrying out ratio test, if the ambiguities pass the ratio test, determining that the ambiguities are successfully fixed, constructing an observed value by using the ambiguities fixed as integers, adding the fixed phase observed value into a tight combination estimator, outputting inertial navigation error estimation by the tight combination estimator, and feeding back the inertial navigation error estimation to an inertial navigation system for error compensation; and if the satellite number does not pass the ratio test, rejecting the satellite with the largest variance, and carrying out ambiguity search and the ratio test again until the satellite number is less than a preset value or the ratio test is passed.
8. The GNSS/INS integrated navigation method of claim 7, wherein if the ambiguity fix process fails to pass through radio test, the floating-point phase observation and the pseudorange observation are input to the close-coupled estimator together, and the close-coupled estimator outputs an inertial navigation error estimate which is fed back to the inertial navigation system for error compensation.
9. An electronic device, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor implements the GNSS/INS combined navigation method according to any one of claims 1 to 8 when executing the computer program.
10. A computer-readable storage medium, having a computer program stored thereon, wherein the computer program is configured to, when executed, implement the GNSS/INS combined navigation method according to any one of claims 1 to 8.
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| CN116660965B (en) * | 2023-07-26 | 2023-09-29 | 北京北斗星通导航技术股份有限公司 | Beidou inertial navigation positioning method, device and storage medium |
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