Satellite positioning precision optimization method in complex environment based on least square method

Abstract

The invention provides a satellite positioning precision optimization method in a complex environment based on a least square method, and the method comprises the steps: S10, collecting a positioning result of a differential satellite navigation receiver under a normal working condition, and taking the positioning result as a reference positioning result; s20, acquiring ephemeris information in a complex environment by using a satellite navigation positioning device; s30, obtaining a positioning precision factor value and a first positioning result; s40, judging whether the positioning precision factor value is within a preset range or not, if so, turning to S50, and otherwise, turning to S20; s50, taking the absolute value of the difference value between the first positioning result and the reference positioning result as the first positioning precision; s60, subtracting the pseudo-range correction from the pseudo-range to obtain an original pseudo-range, and obtaining a second positioning result; taking the absolute value of the difference value between the second positioning result and the reference positioning result as second positioning precision; and S70, judging whether the second positioning precision is smaller than or equal to the first positioning precision, if so, taking the second positioning result as a final positioning result, and otherwise, taking the first positioning result as the final positioning result.

Description

Technical Field

[0001] The present invention relates to the field of navigation and positioning technology, and in particular to a method for optimizing satellite positioning accuracy in a complex environment based on a least squares method. Background Art

[0002] The Global Navigation Satellite System (GNSS) is a satellite-based navigation and positioning system that can provide users with high-precision positioning, speed measurement and timing data. It has the advantages of all-weather, wide coverage and no cumulative error. It has a wide range of application markets in the military and civilian fields. With the continuous changes in the combat environment, high-precision guidance of weapons and equipment has become the most basic combat requirement, but its accuracy is easily interfered with, such as multipath effects, antenna direction obstruction, electromagnetic interference, etc. Satellite navigation and positioning are the basis for the efficient operation of modern weapons and equipment, civil aviation, etc. At present, it is urgent to solve the problem of deterioration of positioning accuracy caused by changes in the direction of the satellite antenna when the satellite navigation receiver dives and rotates. Summary of the invention

[0003] The present invention provides a method for optimizing satellite positioning accuracy in a complex environment based on the least squares method, which can solve the technical problem of low positioning accuracy of existing positioning methods.

[0004] The present invention provides a method for optimizing satellite positioning accuracy in a complex environment based on the least squares method, the method comprising:

[0005] S10, collecting the positioning result of the differential satellite navigation receiver under normal working conditions as a reference positioning result;

[0006] S20, using a satellite navigation and positioning device to obtain ephemeris information in a complex environment, wherein the ephemeris information includes satellite positions, pseudoranges, and pseudorange corrections;

[0007] S30, performing positioning calculation on the ephemeris information to obtain a positioning precision factor value and a first positioning result;

[0008] S40, determining whether the positioning precision factor value is within a preset range, if so, go to S50, otherwise, go to S20;

[0009] S50, taking the absolute value of the difference between the first positioning result and the reference positioning result as the first positioning accuracy;

[0010] S60, subtracting the pseudorange correction amount from the pseudorange to obtain an original pseudorange, performing a weighted least squares calculation based on the satellite position and the original pseudorange to obtain a second positioning result; and taking the absolute value of the difference between the second positioning result and the reference positioning result as a second positioning accuracy;

[0011] S70. Determine whether the second positioning accuracy is less than or equal to the first positioning accuracy. If so, take the second positioning result as the final positioning result; otherwise, take the first positioning result as the final positioning result.

[0012] Preferably, performing weighted least squares calculation based on the satellite position and the original pseudorange to obtain the second positioning result includes:

[0013] Establish positioning solution equation based on each satellite position and original pseudorange;

[0014] Obtain an observation matrix based on the position of each satellite;

[0015] Obtain the weight coefficient of each satellite based on the carrier-to-noise ratio of each satellite, thereby obtaining a weight matrix;

[0016] A weighted least squares calculation is performed on the positioning solution equation based on the observation matrix and the weight matrix to obtain a second positioning result.

[0017] Preferably, the positioning solution equation is established by the following formula:

[0018]

[0019] In the formula, ρ J is the original pseudorange of the Jth satellite, J = 1, 2, 3, 4; X J , Y J , Z J are the X, Y, and Z components of the J-th satellite’s spatial coordinates, respectively. U , Y U , Z U are the X, Y and Z components of the spatial coordinates of the satellite navigation and positioning device, respectively; DLC is the ionospheric delay of the satellite signal; δt u is the clock difference between the local time of the satellite navigation positioning device and the satellite time, and Δρ is the tracking loop error.

[0020] Preferably, the observation matrix is ​​obtained by the following formula:

[0021]

[0022] Where H is the observation matrix.

[0023] Preferably, the weight matrix is ​​obtained by the following formula:

[0024]

[0025] in,

[0026] Where W is the weight matrix, w J is the weight coefficient of the Jth satellite, σ Jis the carrier-to-noise ratio of the Jth satellite.

[0027] Preferably, the second positioning result is obtained by the following formula:

[0028]

[0029] in,

[0030] In the formula, This is the second positioning result.

[0031] Preferably, the preset range is 1-3.

[0032] By applying the technical solution of the present invention, the first positioning result and the first positioning accuracy are obtained by the existing positioning solution method, and the second positioning result and the second positioning accuracy are obtained by the weighted least square method; when the second positioning accuracy is less than or equal to the first positioning accuracy, the second positioning result is used as the final positioning result, and when the second positioning accuracy is greater than the first positioning accuracy, the first positioning result is used as the final positioning result; thereby overcoming the problem of poor positioning accuracy of the satellite navigation receiver antenna in harsh environments and improving the positioning accuracy under terminal attacks. The present invention can solve the technical problem of deterioration of the positioning results of satellite navigation receivers in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 A flowchart of a method for optimizing satellite positioning accuracy in a complex environment based on the least squares method is shown according to an embodiment of the present invention;

[0035] Figure 2 It shows a horizontal error diagram of static natural star collection verification provided according to an embodiment of the present invention;

[0036] Figure 3 It shows an elevation error diagram of static natural star collection verification provided according to an embodiment of the present invention;

[0037] Figure 4 A trajectory diagram of a satellite navigation positioning device provided according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0040] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0041] like Figure 1 As shown, the present invention provides a method for optimizing satellite positioning accuracy in a complex environment based on the least squares method, the method comprising:

[0042] S10, collecting the positioning result of the differential satellite navigation receiver under normal working conditions as a reference positioning result;

[0043] S20, using a satellite navigation and positioning device to obtain ephemeris information in a complex environment, wherein the ephemeris information includes satellite positions, pseudoranges, and pseudorange corrections;

[0044] S30, performing positioning calculation on the ephemeris information to obtain a positioning precision factor value and a first positioning result;

[0045] S40, determining whether the positioning precision factor value is within a preset range, if so, go to S50, otherwise, go to S20;

[0046] S50, taking the absolute value of the difference between the first positioning result and the reference positioning result as the first positioning accuracy;

[0047] S60, subtracting the pseudorange correction amount from the pseudorange to obtain an original pseudorange, performing a weighted least squares calculation based on the satellite position and the original pseudorange to obtain a second positioning result; and taking the absolute value of the difference between the second positioning result and the reference positioning result as a second positioning accuracy;

[0048] S70. Determine whether the second positioning accuracy is less than or equal to the first positioning accuracy. If so, take the second positioning result as the final positioning result; otherwise, take the first positioning result as the final positioning result.

[0049] The present invention obtains the first positioning result and the first positioning accuracy through the existing positioning solution method, and obtains the second positioning result and the second positioning accuracy through the weighted least square method; when the second positioning accuracy is less than or equal to the first positioning accuracy, the second positioning result is used as the final positioning result, and when the second positioning accuracy is greater than the first positioning accuracy, the first positioning result is used as the final positioning result; thereby overcoming the problem of poor positioning accuracy of the satellite navigation receiver antenna in harsh environments and improving the positioning accuracy under terminal attacks. The present invention can solve the technical problem of deterioration of the positioning result of the satellite navigation receiver in complex environments.

[0050] According to an embodiment of the present invention, performing weighted least squares calculation based on the satellite position and the original pseudorange to obtain the second positioning result includes:

[0051] Establish positioning solution equation based on each satellite position and original pseudorange;

[0052] Obtain an observation matrix based on the position of each satellite;

[0053] Obtain the weight coefficient of each satellite based on the carrier-to-noise ratio of each satellite, thereby obtaining a weight matrix;

[0054] A weighted least squares calculation is performed on the positioning solution equation based on the observation matrix and the weight matrix to obtain a second positioning result.

[0055] In order to further understand the present invention, the following Figure 2-Figure 4 The satellite positioning accuracy optimization method under complex environment based on the least squares method of the present invention is described in detail.

[0056] In this embodiment, the reference coordinates of the test point are the coordinates measured by the differential receiver, and the position accuracy error reaches the centimeter level. Based on this, the ephemeris information is the positioning solution data of the satellite receiver in the satellite signal simulator.

[0057] When selecting the test scene, it is necessary to ensure that the positioning precision factor value (PDOP value) is maintained at 1 to 3, or even lower. Otherwise, the positioning accuracy will deteriorate due to the large PDOP value, and the purpose of positioning accuracy analysis under different antenna radiation patterns cannot be achieved.

[0058] During horizontal flight, the satellite antenna faces upward, and the main gain of the antenna is greater when it is facing upward. When the aircraft turns, the carrier rolls, causing the direction of the antenna to change, resulting in the carrier-to-noise ratio of the same satellite changing with the direction of the antenna. When the satellite carrier-to-noise ratio is low, the tracking loop noise increases, and the loop noise affects the pseudo-range accuracy. Positioning solutions are calculated using pseudo-ranges, so when the carrier-to-noise ratio decreases, the position information calculated by the positioning solution will increase.

[0059] Specifically, the positioning solution equation is established by the following formula:

[0060]

[0061] In the formula, ρ J is the original pseudorange of the Jth satellite, J = 1, 2, 3, 4; X J , Y J , Z J are the X, Y, and Z components of the J-th satellite’s spatial coordinates, respectively. U , Y U , Z U are the X, Y and Z components of the spatial coordinates of the satellite navigation and positioning device, respectively; DLC is the ionospheric delay of the satellite signal; δt u is the clock difference between the local time of the satellite navigation positioning device and the satellite time, and Δρ is the tracking loop error.

[0062]

[0063]

[0064] In the above formula (X J ,Y J ,Z J ), the ionospheric parameters are known and can be calculated from the ephemeris broadcast by each satellite. The ionospheric delay of the satellite signal is obtained based on the ionospheric parameters. The pseudorange can be measured by the satellite navigation and positioning device. The only remaining three coordinates of the satellite navigation and positioning device in the equation group (X U ,Y U ,Z U ) and clock error δt uThe solution to the equation is unknown, so if there are four or more available satellite pseudo-range measurements, the solution to the equation can be obtained. When the carrier-to-noise ratio decreases, the tracking loop error Δρ increases. At this time, when solving the equation group, the coordinate error of the satellite navigation positioning device will also increase. On the basis of the original least squares method, the weight is assigned by the satellite's carrier-to-noise ratio. The satellite output value with a larger weight plays a more important role in the least squares method, and satellites with a high carrier-to-noise ratio are selected to participate in the positioning solution.

[0065] The observation matrix is ​​obtained by the following formula:

[0066]

[0067] Where H is the observation matrix. The H matrix is ​​only related to the geometric position of each satellite relative to the satellite navigation positioning device.

[0068] The weight matrix is ​​obtained by the following formula:

[0069]

[0070] in,

[0071] Where W is the weight matrix, w J is the weight coefficient of the Jth satellite, σ J is the carrier-to-noise ratio of the Jth satellite.

[0072] The second positioning result is obtained by the following formula:

[0073]

[0074] in,

[0075] In the formula, This is the second positioning result.

[0076] In this embodiment, the simulation selected the satellite collection test under static conditions, and the test results are as follows: Figure 2 and Figure 3 As shown. The simulation results show that the data using the weighted least squares method for positioning has a certain improvement in height error compared to the least squares method. The weighted least squares method uses the carrier-to-noise ratio to select the weight coefficient and uses satellites with a high carrier-to-noise ratio to participate in positioning, which improves the positioning accuracy to a certain extent when the positioning error is large. This algorithm technology is a relatively mature technology that has undergone vehicle-mounted tests and long-term natural satellite collection tests, and is reliable.

[0077] like Figure 4As shown, it is the trajectory diagram of the satellite navigation and positioning device. Statistical value analysis is carried out on the sports car data. The 1σ statistical value of the height error by the weighted least squares method is 3.79m, the longitude error is 3.49m, and the latitude error is 2.86m, as shown in the following table:

[0078]

[0079] The 1σ statistical value of the height error by the classical least squares method is 5.28m, the longitude error is 4.63m, and the latitude error is 3.86m, as shown in the following table:

[0080]

[0081] The longitude, latitude, and altitude of the weighted least squares are respectively improved by 1.14m, 1m, and 1.16m compared with the longitude, latitude, and altitude calculated by the classical least squares method, as shown in the following table:

[0082] Weighted Least Squares Classical least squares Contrast Enhancement Longitude error (m) 3.49 4.63 1.14m Latitude error (m) 2.86 3.86 1m Height error (m) 3.79 4.95 1.16m

[0083] In summary, the present invention provides a method for optimizing satellite positioning accuracy in a complex environment based on the least squares method, which can more accurately correct the large positioning error caused by the deterioration of the carrier-to-noise ratio of the satellite signals received by the satellite navigation and positioning device due to the continuous change of the antenna pattern under the carrier's diving and rotating state.

[0084] For the sake of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above" and the like can be used here to describe the spatial position relationship of a device or feature shown in the figure with other devices or features. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation described in the figure of the device. For example, if the device in the figure is inverted, the device described as "above other devices or structures" or "over other devices or structures" will be positioned as "below other devices or structures" or "under other devices or structures" afterwards. Thus, the exemplary term "above..." can include both the orientations of "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations will be made for the spatial relative descriptions used here.

[0085] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Without further statement, the above terms have no special meaning, so they cannot be understood as limiting the protection scope of the present invention.

[0086] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for optimizing satellite positioning accuracy in a complex environment based on the least squares method, characterized in that: The method comprises: S10, collecting the positioning result of the differential satellite navigation receiver under normal working conditions as a reference positioning result; S20, using a satellite navigation and positioning device to obtain ephemeris information in a complex environment, wherein the ephemeris information includes satellite positions, pseudoranges, and pseudorange corrections; S30, performing positioning calculation on the ephemeris information to obtain a positioning precision factor value and a first positioning result; S40, determining whether the positioning precision factor value is within a preset range, if so, go to S50, otherwise, go to S20; S50, taking the absolute value of the difference between the first positioning result and the reference positioning result as the first positioning accuracy; S60, subtracting the pseudorange correction amount from the pseudorange to obtain an original pseudorange, performing a weighted least squares calculation based on the satellite position and the original pseudorange to obtain a second positioning result; and taking the absolute value of the difference between the second positioning result and the reference positioning result as a second positioning accuracy; S70. Determine whether the second positioning accuracy is less than or equal to the first positioning accuracy. If so, take the second positioning result as the final positioning result; otherwise, take the first positioning result as the final positioning result.

2. The method according to claim 1, characterized in that Based on the satellite position and the original pseudorange, a weighted least squares calculation is performed to obtain the second positioning result including: Establish positioning solution equation based on each satellite position and original pseudorange; Obtain an observation matrix based on the position of each satellite; Obtain the weight coefficient of each satellite based on the carrier-to-noise ratio of each satellite, thereby obtaining a weight matrix; A weighted least squares calculation is performed on the positioning solution equation based on the observation matrix and the weight matrix to obtain a second positioning result.

3. The method according to claim 1, characterized in that The positioning solution equation is established by the following formula: In the formula, ρ J is the original pseudorange of the Jth satellite, J = 1, 2, 3, 4; X J , Y J , Z J are the X, Y, and Z components of the J-th satellite’s spatial coordinates, respectively. U , Y U , Z U are the X, Y and Z components of the spatial coordinates of the satellite navigation and positioning device, respectively; DLC is the ionospheric delay of the satellite signal; δt u is the clock difference between the local time of the satellite navigation positioning device and the satellite time, and Δρ is the tracking loop error.

4. The method according to claim 1, characterized in that: The observation matrix is ​​obtained by the following formula: Where H is the observation matrix.

5. The method according to claim 1, characterized in that: The weight matrix is ​​obtained by the following formula: in, Where W is the weight matrix, w J is the weight coefficient of the Jth satellite, σ J is the carrier-to-noise ratio of the Jth satellite.

6. The method according to claim 1, characterized in that The second positioning result is obtained by the following formula: in, In the formula, This is the second positioning result.

7. The method according to claim 1, characterized in that The preset range is 1 to 3.

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