Carrier motion acceleration adaptive calculation method based on height information

Abstract

The invention relates to a carrier motion acceleration adaptive calculation method based on height information, and aims to improve the precision of carrier motion acceleration measurement. The method comprises the following steps: judging whether satellite navigation fails or not, and executing different steps according to conditions. When satellite navigation is effective, the satellite navigation height is processed through a damping network, adaptive weighting factors are calculated in combination with the satellite navigation solution state and the carrier motion acceleration in the sliding window, and the final height is obtained through summation. And when the satellite navigation fails, determining the final height according to the final effective damping height and the inertial navigation information. And finally, calculating the motion acceleration of the carrier according to the final height at each moment so as to realize smoothness and stability of height information.

Description

Technical Field

[0001] The invention relates to the field of gravity measurement, and in particular to a method for adaptively calculating carrier motion acceleration based on altitude information. Background Art

[0002] Sea and air gravimeters can measure gravity information over a large range and with high efficiency under dynamic base conditions. Since the 1980s, with the maturity of satellite navigation technology, inertial device technology, and inertial navigation system technology, sea and air gravimeters have made great contributions in resource exploration, gravity mapping, etc. However, due to the limitations of the measurement mechanism, sea and air gravimeters need to measure or suppress the acceleration of the carrier motion to separate the carrier motion acceleration from the gravity acceleration. However, the two types of acceleration information are mutually coupled in the time domain and partially overlap in the frequency domain, which seriously affects the measurement accuracy of the aviation relative gravimeter.

[0003] At present, a lot of research has been done to effectively handle the measurement accuracy of carrier motion acceleration. Existing technology 1 deploys satellite navigation differential base stations near the gravity survey line, performs data analysis and precision mining through offline processing, and verifies the feasibility of using satellite navigation elevation information to calculate motion acceleration through ground vehicle tests. Existing technology 2 is based on the satellite navigation precision single point positioning theory, adopts the position difference method and the phase difference method, and constructs the carrier motion acceleration solution equation in detail, which improves the calculation accuracy of motion acceleration. Existing technology 3 starts from the perspective of physical vibration isolation, and by establishing the motion differential equations of two types of vibration reduction systems for sea and air gravimeters, the corresponding vibration reduction system is designed to reduce the high-frequency interference part of the carrier motion acceleration. Existing technology 4 is based on the aircraft's own motion characteristics, explores how the aircraft's natural motion affects the airborne gravity measurement, and then obtains the spectral characteristics of the aviation gravity measurement error, and determines the relatively accurate low-pass digital filter cutoff frequency to improve the gravity measurement accuracy.

[0004] In terms of motion acceleration processing of sea and air gravimeters, existing technical research is mainly aimed at airborne environments with good satellite navigation signals, and there is relatively little research on motion acceleration processing in the case of short-term loss of satellite navigation signals. With the continuous improvement of human requirements for the resolution and accuracy of gravity information, sea and air gravimeters are gradually oriented towards vehicle-mounted dynamic base application scenarios. However, vehicle-mounted dynamic base application scenarios are often affected by factors such as loss of satellite navigation signals and severe multipath effects. The instability of elevation information limits the calculation of motion acceleration, which is not conducive to gravity measurement. At the same time, due to limitations in labor costs, economic costs, etc., sea and air gravimeters still rely mainly on vehicle-mounted tests for testing after leaving the factory, which places high demands on the vehicle-mounted measurement performance of sea and air gravimeters. Summary of the invention

[0005] The purpose of the present invention is to provide a method for adaptively calculating carrier motion acceleration based on height information, so as to obtain smooth and stable height information and improve the accuracy of carrier motion acceleration measurement.

[0006] In order to solve the above technical problems, the present invention provides a method for adaptively calculating carrier motion acceleration based on height information, comprising the following steps: S1, determine whether the satellite navigation is invalid. If it is not invalid, execute A1~A4; if it is invalid, execute B1; A1. Input the satellite navigation altitude obtained through satellite navigation into the damping network to obtain the damping altitude, and use the damping altitude as the inertial navigation altitude; A2. Obtaining a first weighted evaluation value according to the solution state of the satellite navigation within a set sliding window time; A3. Obtain a second weight evaluation value according to the carrier motion acceleration within the set sliding window time; A4. Obtaining an adaptive weighting factor according to the first weight evaluation value and the second weight evaluation value; A5. Weighted sum of the satellite navigation altitude and the inertial navigation altitude according to the adaptive weighting factor to obtain the final altitude; B1. Determine the final altitude when satellite navigation fails based on the last value of the damping altitude when satellite navigation is valid and the inertial navigation information obtained through inertial navigation; S2. Obtain the carrier motion acceleration according to the final height at different times. According to the above scheme, the damping network is a second-order damping network.

[0007] According to the above scheme, the method for obtaining the first weighted evaluation value is to perform the following judgment on each solution state according to the priority of the solution state from high to low within the set sliding window time: When the duration of the solution state within the sliding window time exceeds the set time threshold of the solution state, the first weight evaluation value corresponding to the solution state is output, and the judgment of the solution state with a lower priority is stopped.

[0008] According to the above scheme, in descending order of priority, the solution status of satellite navigation includes fixed solution, floating solution, single point solution, no solution, and others.

[0009] According to the above scheme, the method for obtaining the second weighted evaluation value is to obtain the second weighted evaluation value according to the peak value and standard deviation of the carrier motion acceleration within the set sliding window time and the set carrier motion acceleration judgment threshold.

[0010] According to the above scheme, the method for obtaining the adaptive weighting factor is to use the maximum value of the first weight evaluation value and the second weight evaluation value as the adaptive weighting factor.

[0011] According to the above scheme, the method for obtaining the carrier motion acceleration performs differential operation according to the final height at different times to obtain the initial value of the carrier motion acceleration; and performs low-pass filtering on the initial value of the carrier motion acceleration to obtain the carrier motion acceleration.

[0012] The present invention also provides a carrier motion acceleration adaptive calculation device based on height information, comprising: A satellite navigation failure judgment module is used to judge whether the satellite navigation has failed. If it has not failed, the damping height acquisition module, the first weight evaluation value acquisition module, the second weight evaluation value acquisition module, the adaptive weighting factor acquisition module, and the first final height acquisition module are enabled. If it fails, the second final height acquisition module is enabled. A damping height acquisition module is used to input the satellite navigation height acquired through satellite navigation into the damping network to acquire the damping height; A first weight evaluation value acquisition module is used to determine the solution state of the satellite navigation within a set sliding window time; A second weight evaluation value acquisition module, used to obtain a second weight evaluation value according to the carrier motion acceleration within a set sliding window time; An adaptive weighting factor acquisition module, used to obtain an adaptive weighting factor according to the first weight evaluation value and the second weight evaluation value; A first final altitude acquisition module is used to perform weighted summation of the satellite navigation altitude and the inertial navigation altitude according to an adaptive weighting factor to obtain a final altitude; A second final altitude acquisition module is used to determine the final altitude when the satellite navigation fails according to the last moment value of the damping altitude when the satellite navigation is valid and the inertial navigation information obtained by the inertial navigation; The carrier motion acceleration acquisition module is used to obtain the carrier motion acceleration according to the final height at different times.

[0013] According to the above scheme, the method for obtaining the first weighted evaluation value is to perform the following judgment on each solution state according to the priority of the solution state from high to low within the set sliding window time: When the duration of the solution state within the sliding window time exceeds the set time threshold of the solution state, the first weight evaluation value corresponding to the solution state is output, and the judgment of the solution state with a lower priority is stopped.

[0014] According to the above scheme, the method for obtaining the second weighted evaluation value is to obtain the second weighted evaluation value according to the peak value and standard deviation of the carrier motion acceleration within the set sliding window time and the set carrier motion acceleration judgment threshold.

[0015] Beneficial Effects The present invention adopts different methods to obtain altitude information when the satellite navigation fails and when it does not fail. When the satellite navigation does not fail, the satellite navigation altitude is processed by taking into account the carrier motion acceleration at past moments and the solution state of the satellite navigation, so that the acquired carrier motion acceleration is smoother. When the satellite navigation fails, the carrier motion acceleration is obtained in combination with the inertial navigation, so as to fill the altitude information gap when the satellite navigation altitude is missing and ensure the stability of the carrier motion acceleration. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a flow chart of a method for adaptively calculating carrier motion acceleration based on height information according to a first embodiment of the present invention; Figure 2 It is a schematic diagram of a characteristic curve of a low-pass digital filter according to the first embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0018] Embodiment 1: See also Figure 1 This embodiment provides a method for adaptively calculating carrier motion acceleration based on height information, comprising the following steps: S1, determine whether the satellite navigation is invalid. If it is not invalid, execute A1~A4; if it is invalid, execute B1; A1. Input the satellite navigation altitude obtained through satellite navigation into the damping network to obtain the damping altitude, and use the damping altitude as the inertial navigation altitude; A2. Obtaining a first weighted evaluation value according to the solution state of the satellite navigation within a set sliding window time; A3. Obtain a second weight evaluation value according to the carrier motion acceleration within the set sliding window time; A4. Obtaining an adaptive weighting factor according to the first weight evaluation value and the second weight evaluation value; A5. Weighted sum of the satellite navigation altitude and the inertial navigation altitude according to the adaptive weighting factor to obtain the final altitude; B1. Determine the final altitude when satellite navigation fails based on the last value of the damping altitude when satellite navigation is valid and the inertial navigation information obtained through inertial navigation; S2. Obtain the carrier motion acceleration according to the final height at different times. Furthermore, the damping network is a second-order damping network; it should be understood that the second-order damping network is an existing signal processing network, and there are many related network structures in the prior art. Those skilled in the art can set them according to actual needs, and they will not be described in detail in this embodiment.

[0019] Furthermore, the method for obtaining the first weighted evaluation value is to perform the following judgment on each solution state according to the priority of the solution state from high to low within the set sliding window time: When the duration of the solution state within the sliding window time exceeds the set time threshold of the solution state, the first weight evaluation value corresponding to the solution state is output, and the judgment of the solution state with a lower priority is stopped; In this embodiment, the duration of the sliding window time T is set to 10-20 seconds.

[0020] Further, according to the order of priority from high to low, the solution status of satellite navigation includes fixed solution, floating solution, single point solution, no solution, and others; In this embodiment, referring to the satellite navigation NAME0183 protocol, the following table is provided: .

[0021] The first weighted evaluation value It is expressed as:

[0022] In the above formula, is the weight result, For order.

[0023] Furthermore, the second weight evaluation value is obtained by obtaining the second weight evaluation value according to the peak value and standard deviation of the carrier motion acceleration within the set sliding window time and the set carrier motion acceleration judgment threshold; In this embodiment, the second weight evaluation value It is expressed as:

[0024] In the above formula, , are the peak value and standard deviation of the carrier motion acceleration within the set sliding window time, which respectively reflect the variation amplitude and stability of the carrier motion; is the carrier motion acceleration judgment threshold, which needs to be determined in combination with the actual carrier motion characteristics. In this embodiment, the value is 0.2 mm / s 2 .

[0025] Furthermore, the method for obtaining the adaptive weighting factor is to use the maximum value of the first weight evaluation value and the second weight evaluation value as the adaptive weighting factor; In this embodiment, the adaptive weighting factor It is expressed as: .

[0026] In this embodiment, the final height It is expressed as:

[0027] In the above formula, is the satellite navigation altitude, is the inertial navigation altitude.

[0028] Furthermore, the method for obtaining the carrier motion acceleration performs differential calculation according to the final height at different times to obtain the initial value of the carrier motion acceleration; performs low-pass filtering on the initial value of the carrier motion acceleration to obtain the carrier motion acceleration; In this embodiment, the initial value of the carrier motion acceleration It is expressed as:

[0029] In the above formula, , , is the sequence of final height changes over time, is the minimum time interval between the final heights at different times, which is 1 to 0.5 s in this embodiment.

[0030] In this embodiment, the low-pass digital filter used for low-pass filtering adopts the Hann window function method. Taking the cut-off frequency of 0.005 Hz as an example, the corresponding low-pass digital filter characteristic curve is shown in Figure 2 .

[0031] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0032] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for adaptively calculating carrier motion acceleration based on height information, characterized in that: The following steps are involved: S1, determine whether the satellite navigation is invalid. If it is not invalid, execute A1~A4; if it is invalid, execute B1; A1. Input the satellite navigation altitude obtained through satellite navigation into the damping network to obtain the damping altitude, and use the damping altitude as the inertial navigation altitude; A2. Obtaining a first weighted evaluation value according to the solution state of the satellite navigation within a set sliding window time; A3. Obtain a second weight evaluation value according to the carrier motion acceleration within the set sliding window time; A4. Obtaining an adaptive weighting factor according to the first weight evaluation value and the second weight evaluation value; A5. Weighted sum of the satellite navigation altitude and the inertial navigation altitude according to the adaptive weighting factor to obtain the final altitude; B1. Determine the final altitude when satellite navigation fails based on the last value of the damping altitude when satellite navigation is valid and the inertial navigation information obtained through inertial navigation; S2. Obtain the carrier motion acceleration according to the final height at different times.

2. The method for adaptively calculating carrier motion acceleration based on height information according to claim 1, characterized in that: The damping network is a second-order damping network.

3. The method for adaptively calculating carrier motion acceleration based on height information according to claim 1, characterized in that: The method for obtaining the first weighted evaluation value is to perform the following judgment on each solution state according to the priority of the solution state from high to low within the set sliding window time: When the duration of the solution state within the sliding window time exceeds the set time threshold of the solution state, the first weight evaluation value corresponding to the solution state is output, and the judgment of the solution state with a lower priority is stopped.

4. The method for adaptively calculating carrier motion acceleration based on height information according to claim 3, characterized in that: According to the order of priority from high to low, the solution status of satellite navigation includes fixed solution, floating solution, single point solution, no solution, and others.

5. The method for adaptively calculating carrier motion acceleration based on height information according to claim 1, characterized in that: The second weight evaluation value is obtained by using a peak value and a standard deviation of the carrier motion acceleration within a set sliding window time and a set carrier motion acceleration judgment threshold to obtain the second weight evaluation value.

6. The method for adaptively calculating carrier motion acceleration based on height information according to claim 1, characterized in that: The method for obtaining the adaptive weighting factor is to use the maximum value of the first weight evaluation value and the second weight evaluation value as the adaptive weighting factor.

7. The method for adaptively calculating carrier motion acceleration based on height information according to claim 1, characterized in that: The method for obtaining the carrier motion acceleration is to perform differential operation according to the final height at different times to obtain the initial value of the carrier motion acceleration; and to perform low-pass filtering on the initial value of the carrier motion acceleration to obtain the carrier motion acceleration.

8. A carrier motion acceleration adaptive calculation device based on height information, characterized in that: include: A satellite navigation failure judgment module is used to judge whether the satellite navigation has failed. If it has not failed, the damping height acquisition module, the first weight evaluation value acquisition module, the second weight evaluation value acquisition module, the adaptive weighting factor acquisition module, and the first final height acquisition module are enabled. If it fails, the second final height acquisition module is enabled. A damping height acquisition module is used to input the satellite navigation height acquired through satellite navigation into the damping network to acquire the damping height; A first weight evaluation value acquisition module is used to determine the solution state of the satellite navigation within a set sliding window time; A second weight evaluation value acquisition module, used to obtain a second weight evaluation value according to the carrier motion acceleration within a set sliding window time; An adaptive weighting factor acquisition module, used to obtain an adaptive weighting factor according to the first weight evaluation value and the second weight evaluation value; A first final altitude acquisition module is used to perform weighted summation of the satellite navigation altitude and the inertial navigation altitude according to an adaptive weighting factor to obtain a final altitude; A second final altitude acquisition module is used to determine the final altitude when the satellite navigation fails according to the last moment value of the damping altitude when the satellite navigation is valid and the inertial navigation information obtained by the inertial navigation; The carrier motion acceleration acquisition module is used to obtain the carrier motion acceleration according to the final height at different times.

9. The carrier motion acceleration adaptive calculation device based on height information according to claim 8, characterized in that: The method for obtaining the first weighted evaluation value is to perform the following judgment on each solution state according to the priority of the solution state from high to low within the set sliding window time: When the duration of the solution state within the sliding window time exceeds the set time threshold of the solution state, the first weight evaluation value corresponding to the solution state is output, and the judgment of the solution state with a lower priority is stopped.

10. The carrier motion acceleration adaptive calculation device based on height information according to claim 8, characterized in that: The second weight evaluation value is obtained by using a peak value and a standard deviation of the carrier motion acceleration within a set sliding window time and a set carrier motion acceleration judgment threshold to obtain the second weight evaluation value.

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