A GNSS-based fast positioning method

Abstract

The invention discloses a GNSS-based rapid positioning method, which relates to the field of satellite positioning technology. The GNSS satellite signal is captured and tracked by a receiver to obtain tracking loop information; a reference pseudo-moment is calculated when the approximate position of the receiver, the approximate time of the receiver and the satellite ephemeris are known; the reference pseudo-moment is processed by the tracking loop information to obtain a virtual pseudo-range; the virtual pseudo-range is corrected by inverse calculation of the residual; finally, the corrected virtual pseudo-range is used as the observation pseudo-range to solve the positioning equation group, and the positioning result is obtained by iterative solution. By setting the virtual pseudo-range, the traditional positioning equation group is improved, and the frame synchronization and bit synchronization of the satellite signal are skipped, so that positioning can be achieved and the positioning speed is improved.

Description

Technical Field

[0001] The present invention relates to the field of satellite positioning technology, and more specifically, to a rapid positioning method based on GNSS. Background Art

[0002] At present, GNSS satellite positioning mainly obtains the transmission time of satellite signals through user receivers to capture, track, synchronize bits and frames of satellite signals. Then, the receiving time t of the user receiver is r Subtract the time when the satellite signal was transmitted Multiply it by the speed of light c to get the pseudorange. Finally, by measuring the pseudoranges from different satellites to the user's receiver, sufficient positioning equations are combined to solve the positioning.

[0003] However, in the above process, the user receiver needs to spend a lot of time to capture, track, bit synchronize and frame synchronize the satellite signal in order to obtain the signal transmission time, resulting in a slow positioning speed. Summary of the invention

[0004] The purpose of the present invention is to provide a fast positioning method based on GNSS, which sets a virtual pseudorange, directly uses the virtual pseudorange as the observation pseudomoment, and solves the positioning by jointly solving the positioning equations. It does not require an accurate receiver local clock, skips the steps of frame synchronization and bit synchronization of the receiver to the satellite signal, and speeds up the positioning speed.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions:

[0006] A GNSS-based rapid positioning method comprises the following steps:

[0007] S1: Obtain the approximate position of the receiver, the approximate time of the receiver and the satellite ephemeris; receive signals from GNSS satellites and capture and track the received GNSS satellite signals to obtain tracking loop information; the tracking loop information includes the code cycle count, code phase value, code cycle width, single code chip cycle width and cycle bit width time of the tracking loop.

[0008] S2: Processing the acquired receiver approximate position, receiver approximate time and satellite ephemeris to obtain a reference pseudo-moment;

[0009] S3: Process the reference pseudo-moment by tracking loop information to obtain a virtual pseudo-range;

[0010] S4: Correcting the virtual pseudorange by using the reference pseudomoment to obtain a corrected virtual pseudorange;

[0011] S5: Using the corrected virtual pseudorange as the observed pseudorange to solve the positioning equation group, and obtaining the positioning result by solving the positioning equation group.

[0012] The present invention sets a virtual pseudorange, uses the virtual pseudorange as the observed pseudorange to directly perform positioning and solving, does not need to perform frame synchronization and bit synchronization on GNSS satellite signals, and improves positioning speed; the present invention calculates a reference pseudomoment by using the acquired receiver approximate position, receiver approximate time, satellite ephemeris and tracking loop information, processes the reference pseudomoment by using the acquired tracking loop information to obtain the virtual pseudorange, corrects the virtual pseudorange to obtain the corrected virtual pseudorange, and finally uses the corrected virtual pseudorange as the observed pseudomoment to solve a positioning solution equation group, and solves the positioning result.

[0013] Further, step S2 is specifically as follows:

[0014] S21: Obtain the average propagation time of satellite signals;

[0015] S22: Calculate the average propagation time of satellite signals, the approximate receiver time, and the satellite ephemeris through the GNSS ephemeris algorithm to obtain the initial satellite position and the initial satellite clock error;

[0016] S23: The initial satellite position, the initial satellite clock error and the approximate position of the receiver are calculated by a formula to obtain a reference pseudorange.

[0017] Furthermore, the following formula is used for calculation:

[0018]

[0019] Among them, P r represents the reference pseudorange, X s represents the initial satellite position, X r represents the approximate position of the receiver, Δts represents the initial satellite clock error, c represents the speed of light, and the superscript i represents the satellite number.

[0020] By adopting the above scheme, a reference pseudo moment is calculated to provide a reference value for the subsequent calculation of the virtual pseudo range.

[0021] Further, step S3 is specifically as follows:

[0022] S31: Calculate the code cycle count, code phase value, code cycle width, single chip cycle width, cycle bit width time and receiver signal reception time through a formula to obtain the bit width remainder part of the real pseudorange;

[0023] S32: Process the reference pseudorange using the bit width remainder of the real pseudorange and the periodic bit width time to obtain a virtual pseudorange.

[0024] Furthermore, the virtual pseudorange is obtained through the following formula processing:

[0025]

[0026] where P v represents the virtual pseudorange, P f represents the bit-width remainder part of the true pseudorange, P r represents the reference pseudorange, T bit represents the cycle bit-width time, c represents the speed of light, represents P r divided by T bit C.

[0027] Adopting the above scheme, the virtual pseudorange is set based on the bit-width remainder part of the true pseudorange and the reference pseudorange, and the positioning solution equations can be directly solved through the virtual pseudorange to perform positioning.

[0028] Furthermore, step S4 is specifically as follows:

[0029] S41: Calculate the satellite residuals through the virtual pseudorange and the reference pseudorange;

[0030] S42: Correct the virtual pseudorange through the satellite residuals and the cycle bit-width time;

[0031] Furthermore, the virtual pseudorange is corrected through the following method:

[0032]

[0033] where P' v represents the corrected virtual pseudorange, P v represents the virtual pseudorange, T bit represents the cycle bit-width time, c represents the speed of light, res represents the satellite residuals, the superscript i base represents the reference satellite, and the superscript j represents the other satellites.

[0034] Adopting the above scheme, the virtual pseudorange is corrected, so that the corrected virtual pseudorange can be used as the observed pseudorange for positioning.

[0035] Furthermore, step S5 is specifically as follows:

[0036] S51: Use the corrected virtual pseudorange as the observed pseudorange, and calculate the satellite position, satellite clock offset, and satellite speed through the ephemeris algorithm of GNSS;

[0037] S52: Linearize the satellite position, receiver position, and receiver clock offset as independent variables to obtain the observation equation;

[0038] S53: Combine the observation quantity equations to obtain the positioning solution equation group, and iteratively solve them to obtain the positioning result.

[0039] Further, the positioning solution equation group is:

[0040] [ΔX r Δt ui Δt uf ]=(H T PH) -1 H T PΔb

[0041] Where H represents the method matrix, P represents the weight matrix, Δb represents the observation vector, ΔXr represents the approximate position change of the receiver, and Δt ui Indicates the receiver clock error change above the bit width, Δt uf Indicates the receiver clock error change below the bit width.

[0042] Furthermore, the normal matrix and the observation vector are:

[0043]

[0044]

[0045] Among them, A (i) represents the unit observation vector from the user terminal to the satellite, V (i) represents the velocity vector of the i-th satellite, ρ (i) Represents the observed pseudorange, R0 (i) represents the distance between the star and the earth, c represents the speed of light, and t uf Indicates the receiver clock error below the bit width.

[0046] By adopting the above scheme, the corrected virtual pseudorange is used as the observed pseudorange to construct the positioning solution equation group.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The present invention provides a GNSS-based rapid positioning method, which sets a virtual pseudorange, directly uses the virtual pseudorange as an observation pseudomoment, and solves the positioning by jointly solving a positioning solution equation group. It does not require an accurate receiver local clock, skips the steps of frame synchronization and bit synchronization of the receiver for satellite signals, and saves positioning time. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0050] Figure 1 The following is a flow chart of an embodiment. Detailed implementation mode

[0051] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the embodiments and the accompanying drawings. The illustrative embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0052] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is obvious to those of ordinary skill in the art that: these specific details do not have to be adopted to implement the present invention. In other instances, well-known structures, circuits, materials or methods have not been specifically described in order to avoid obscuring the present invention.

[0053] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention.

[0054] Throughout the specification, the mention of "an embodiment", "embodiment", "an example" or "example" means that: the specific features, structures or characteristics described in connection with the embodiment or example are included in at least one embodiment of the present invention. Therefore, the phrases "an embodiment", "embodiment", "an example" or "example" that appear throughout the specification do not necessarily all refer to the same embodiment or example. In addition, the specific features, structures or characteristics can be combined in any appropriate combination and / or sub-combination in one or more embodiments or examples. In addition, those of ordinary skill in the art should understand that the diagrams provided herein are for illustrative purposes only, and the term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0055] Embodiment: A fast positioning method based on GNSS

[0056] As Figure 1 shown:

[0057] In the case where the known ephemeris and the approximate position of the receiver are less than 1500 kilometers and the local clock error is less than 10 seconds, fast positioning can be performed by the following method.

[0058] A1: The receiver receives signals from GNSS satellites through a radio frequency antenna, captures and tracks the received GNSS satellite signals, and obtains tracking loop information; the loop information includes the code period count N CA of the tracking loop, the code phase value Code period width T CA and single chip period width T chip as well as cycle bit width time T bit .

[0059] A2: Obtain the approximate position X of the receiver r , the approximate time t of the receiver r and the satellite ephemeris eph (i) ; It can be obtained through the backup information maintained by the user terminal itself, obtained from network sources or manually input through other external information.

[0060] A3: Use the approximate time t of the receiver obtained in A2 r , the satellite ephemeris eph (i) (in this embodiment, the superscript i represents the i-th satellite) and the average propagation time Δt of the satellite signal trans Calculate through the GNSS ephemeris algorithm to obtain the initial satellite position Xs and the initial satellite clock error Δts:

[0061] [Xs (i) Δts (i) = [xs (i) ys (i) zs (i) Δts (i) = f(eph (i) , t r - Δ ttrans )

[0062] A4: Calculate the reference pseudorange P through the initial satellite position Xs, the initial satellite clock error Δts and the approximate position X of the receiver r : r

[0063]

[0064] Among them, c represents the speed of light. In this embodiment, c represents the speed of light without special instructions.

[0065] A5: Combine the tracking loop information obtained in A1 and the approximate time t of the receiver obtained in A2 r Calculate the width remainder part P of the true pseudorange f :

[0066] First, use the code period count N CA of the tracking loop obtained in A1, the code phase value the code period width T CA and the single chip period width T chip to calculate the time t f below the width of the observable through the formula; ​

[0067]

[0068] Re - utilize the time t of the part below the observable bit - width f , the periodic bit - width time T obtained by A1 bit Combine with the approximate receiver time t obtained by A2 r , and calculate the bit - width remainder part P of the true pseudorange according to the formula f :

[0069] P f = mod((t r - t f ), T bit )·c

[0070] A6: Utilize the bit - width remainder part P of the true pseudorange f and the periodic bit - width time T bit to process the reference pseudorange P in A4 r to obtain the virtual pseudorange P v :

[0071]

[0072] wherein represents P r divided by T bit C.

[0073] A7: Calculate the satellite residual res through the virtual pseudorange P v and the reference pseudorange P r . Correct the virtual pseudorange P through the satellite residual res and the periodic bit - width time T bit : v

[0074] Calculate the satellite residual res through the virtual pseudorange P v and the reference pseudorange P r :

[0075]

[0076] Correct the virtual pseudorange P through the satellite residual res and the periodic bit - width time T bit to obtain the corrected virtual pseudorange P′ v : v :

[0077]

[0078] wherein, the superscript i base represents the reference satellite, and the superscript j represents the remaining satellites.

[0079] A8: The corrected virtual pseudorange P′ v As the observed quantity, we get the observed quantity equation:

[0080] The corrected virtual pseudorange P′ v As the observed pseudorange, the satellite position Xs, satellite clock error Δts and satellite velocity V are recalculated through the GNSS ephemeris algorithm:

[0081] [Xs (i) V (i) Δts (i) ]==f(eph (i) , t r -P′ v / c)

[0082] The satellite position, the approximate position of the receiver and the local clock error are used as independent variables for Taylor expansion to obtain the observation equation:

[0083]

[0084] Among them, ρ (i) Represents the pseudorange observation, R0 (i) represents the distance between the satellite and the earth, t uf Indicates the local clock error below the bit width, V (i) represents the velocity vector of the i-th satellite, Δt uf Indicates the change in local clock error below the bit width, Δt ui Indicates the change in local clock error above the bit width, A (i) Represents the unit observation vector from the user terminal to the satellite.

[0085] A9: Combine the observation equations in A8 to obtain the positioning solution equations, and solve them iteratively:

[0086] [ΔX r Δt ui Δt uf ]=(H T PH) -1 H T PΔb

[0087] in,

[0088]

[0089]

[0090] P is the weight matrix, which is generally a diagonal matrix. To avoid iterative divergence, H T PH is used for pathological determination and correction.

[0091] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, 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 GNSS-based fast positioning method, characterized in that, The following steps are involved: S1: Obtain the receiver approximate position, receiver approximate time, satellite ephemeris and tracking loop information of GNSS satellite signals; The tracking loop information includes a code cycle count, a code phase value, a code cycle width, a single chip cycle width, and a cycle bit width time of the tracking loop; S2: Processing the acquired approximate position of the receiver, the approximate time of the receiver and the satellite ephemeris to obtain a reference pseudo-moment; S3: Processing the reference pseudo moment using the tracking loop information to obtain a virtual pseudo range; S4: Correcting the virtual pseudorange using the reference pseudo-moment to obtain a corrected virtual pseudorange; S5: Using the corrected virtual pseudorange as the observed pseudorange to solve a positioning equation group, and obtaining a positioning result by solving the positioning equation group.

2. The GNSS-based rapid positioning method according to claim 1, wherein step S2 is specifically: S21: Obtain the average propagation time of satellite signals; S22: Calculate the satellite signal average propagation time, receiver approximate time and satellite ephemeris through the GNSS ephemeris algorithm to obtain an initial satellite position and an initial satellite clock error; S23: Calculate the initial satellite position, initial satellite clock error and approximate receiver position through a formula to obtain a reference pseudorange.

3. A GNSS-based rapid positioning method according to claim 2, characterized in that, The reference pseudorange is calculated by the following formula: ； where P r represents the reference pseudorange, Xs represents the initial satellite position, and X r represents the approximate receiver position, represents the initial satellite clock offset, c represents the speed of light, and the superscript i represents the satellite number.

4. A GNSS-based rapid positioning method according to claim 1, characterized in that, The step S3 is specifically as follows: S31: Calculate the code cycle count, code phase value, code cycle width, single chip cycle width, cycle bit width time and receiver approximate time through a formula to obtain a bit width remainder part of the real pseudorange; S32: Processing the reference pseudorange using the bit width remainder part and the periodic bit width time of the real pseudorange to obtain a virtual pseudorange.

5. A GNSS-based rapid positioning method according to claim 4, wherein The virtual pseudorange is obtained by the following formula: Among them, P v represents the virtual pseudorange, P f represents the bit-width remainder part of the true pseudorange, P r represents the reference pseudorange, T bit represents the period bit-width time, c represents the speed of light, represents P r divisible by T bit c.

6. A GNSS-based fast positioning method according to claim 1, characterized in that, The step S4 is specifically as follows: S41: Calculating satellite residuals using the virtual pseudorange and the reference pseudorange; S42: Correcting the virtual pseudorange by using the satellite residual and the periodic bit width time.

7. A GNSS-based fast positioning method according to claim 6, characterized in that, The virtual pseudorange is corrected by the following method: Among them, represents the corrected virtual pseudorange, P v represents the virtual pseudorange, T bit represents the period bit-width time, c represents the speed of light, res represents the satellite residual, and the superscript i base represents the reference satellite, and the superscript j represents the other satellites.

8. According to the GNSS-based rapid positioning method of claim 1, the step S5 specifically comprises: S51: using the corrected virtual pseudorange as the observed pseudorange, and calculating the satellite position, satellite clock error and satellite velocity through the GNSS ephemeris algorithm; S52: linearize the satellite position, the receiver position and the receiver clock error as independent variables to obtain the observation equation; S53: Combine the observation equations to obtain a positioning solution equation group, and iteratively solve them to obtain a positioning result.

9. A GNSS-based fast positioning method according to claim 8, characterized in that, The positioning solution equation group is: Among them, H represents the normal matrix, and P represents the weight matrix. represents the observation vector, represents the approximate position change of the receiver, represents the receiver clock error change above the bit width, represents the receiver clock error change below the bit width.

10. A GNSS-based rapid positioning method according to claim 9, characterized in that: Among them, represents the unit observation vector from the user terminal to the satellite, represents the velocity vector of the i-th satellite, represents the observed pseudorange, represents the satellite-ground distance, c represents the speed of light, t uf represents the receiver clock error below the bit width.

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