Geophysical field matching navigation suitability analysis method based on deviation estimation

Abstract

The invention provides a geophysical field matching navigation suitability analysis method based on deviation estimation. The method comprises the following steps: firstly, dividing nodes in an adaptability analysis window; determining a geophysical field characteristic value of each node according to the geophysical field background image; according to the prior probability distribution type of the real position and a matching algorithm to be used, a longitude matching deviation model and a latitude matching deviation model matched with the geophysical field are determined respectively, and then prior probability distribution parameters and the geophysical field characteristic value of each node are substituted to obtain estimated longitude and latitude overall matching deviation; and measuring the longitude suitability of the geophysical field matching navigation by adopting the estimated longitude overall matching deviation, and measuring the latitude suitability of the geophysical field matching navigation by adopting the estimated latitude overall matching deviation, thereby realizing suitability analysis. By using the method, the suitability of geophysical field matching navigation can be quantitatively measured by using the estimated matching deviation, and meanwhile, the suitability of longitude and latitude can be distinguished.

Description

Technical Field

[0001] The present invention relates to the field of navigation, guidance and control technology, and in particular to a geophysical field matching navigation adaptability analysis method based on deviation estimation. Background Art

[0002] Navigation technology is one of the key technologies for sea, land and air navigation. It directly determines whether the vehicle can navigate safely and accurately reach the designated operating location. It is a key factor in determining the success or failure of the mission.

[0003] The inertial navigation system has the advantages of autonomy and concealment. It can perform high-precision navigation in a short period of time. It is one of the most important navigation methods and is usually used as the main navigation and positioning system in integrated navigation. However, its navigation error accumulates over time, and it is easy to produce large positioning errors during long-term operation. Therefore, long-duration navigation requires the use of other navigation sensors or navigation systems for correction.

[0004] The basic principle of geophysical field matching navigation is to compare the geophysical field background map accurately obtained in advance in the spacecraft with the geophysical field characteristics of the spacecraft's position continuously measured by the sensor, so as to obtain the position of the spacecraft. According to different geophysical parameters, geophysical field matching navigation mainly includes terrain matching navigation, gravity matching navigation and geomagnetic matching navigation.

[0005] Suitability analysis is the basis of geophysical matching navigation. When matching is performed in areas with a lack of features and poor adaptability, it may lead to larger errors. Traditional adaptability analysis is often based on characteristic statistical parameters, and the threshold is difficult to determine. Most of them can only qualitatively describe the quality of the matching effect, but cannot quantitatively analyze the matching deviation (matching accuracy), and cannot give an analytical formula for the matching deviation (matching accuracy). In addition, traditional methods often regard adaptability as a feature of the geophysical field background map itself, rather than the capabilities of the system including the search window, observation accuracy, geophysical field background map, and matching algorithm, and cannot comprehensively and accurately evaluate the quality of the matching effect. At the same time, although traditional methods can show the characteristic differences of longitude and latitude to a certain extent, they cannot clearly distinguish the matching areas of longitude and latitude. Summary of the invention

[0006] In view of this, the present invention provides a geophysical field matching navigation adaptability analysis method based on deviation estimation, which can quantitatively measure the adaptability of geophysical field matching navigation with the estimated matching deviation, and can distinguish the adaptability of each longitude and latitude.

[0007] In order to solve the above technical problems, the present invention is implemented as follows.

[0008] A geophysical field matching navigation adaptability analysis method based on deviation estimation, the method comprising:

[0009] Step 1: In the given adaptability analysis window S ear Perform node division inside to obtain i×j nodes;

[0010] Step 2: Input the geophysical field background map and determine the geophysical field characteristic value of each node;

[0011] Step 3: According to the prior probability distribution type of the real position and the matching algorithm to be used, the longitude matching deviation model and the latitude matching deviation model of the geophysical field matching are determined respectively;

[0012] Step 4: Substitute the distribution parameters corresponding to the prior probability distribution type and the geophysical field characteristic values ​​of each node into the model determined in step 3 to obtain the estimated overall longitude matching deviation β x and the overall matching deviation of latitude β y ;

[0013] Step 5: Use the estimated longitude overall matching deviation β x To measure the longitude adaptability of geophysical field matching navigation, the estimated latitude overall matching deviation β is used y Measure the latitude adaptability of geophysical field matching navigation and implement adaptability analysis.

[0014] Preferably, in step 3, according to the prior probability distribution type of the real position and the matching algorithm to be used, the overall longitude matching deviation model and the overall latitude matching deviation model of the geophysical field matching are respectively determined as follows:

[0015] Step 31: Taking the position of the spacecraft as an estimate;

[0016] Step 32: Determine the prior probability distribution of the position according to the prior conditions;

[0017] Step 33: The observation result of the characteristic value of the geophysical field is determined by the characteristics of the geophysical field at the position of the spacecraft and is affected by the observation error; according to the characteristics of the observation error and the geophysical field background map, the conditional probability distribution of the observation value of the characteristic value of the geophysical field to the position of the spacecraft is obtained;

[0018] Step 34: Assume a true position of a spacecraft as condition 1, and obtain an estimate of the posterior probability distribution of the spacecraft position under condition 1 based on the conditional probability distribution of the geophysical field eigenvalue observations on the spacecraft position, the selected matching algorithm, and the observation error characteristics;

[0019] Step 35: Based on the posterior probability distribution estimation of the aircraft position under condition 1 in step 34, obtain the estimated value of the position under condition 1; compare with the assumed true position to obtain the matching deviation of the estimate under condition 1;

[0020] Step 36: Since the estimated matching deviation obtained in step 35 is based on a certain assumed real position, all possible real positions are traversed, and steps 34-35 are repeated. Combined with the prior probability distribution of the real position, an estimate of the overall matching deviation within the search range is obtained.

[0021] Preferably, the matching algorithm is based on Bayesian estimation.

[0022] Preferably, the prior probability distribution type is the adaptability analysis window S ear The uniform distribution within the geophysical field is σ, and the observation standard deviation of the characteristic value of the geophysical field is σ; the matching algorithm adopts particle filtering or its derivative algorithm; then the overall longitude matching deviation model and latitude matching deviation model of the geophysical field matching are:

[0023]

[0024] Among them, β x The adaptability analysis window S ear The overall matching bias estimate for longitude within β y The adaptability analysis window S ear The overall matching deviation estimate for the latitude within The adaptability analysis window S ear Any node in The characteristic value of the geophysical field at The adaptability analysis window S ear Any node in The characteristic value of the geophysical field at the node is the adaptability analysis window S ear The possible real positions within need to be traversed. Is a node The characteristic values ​​of the geophysical field at .

[0025] Preferably, the range of particle filtering is used as the adaptability analysis window S ear .

[0026] Preferably, for the longitude overall matching deviation β x and the overall matching deviation of latitude β y Criteria are set respectively, and suitability analysis of longitude and latitude is performed based on the criteria respectively.

[0027] Preferably, in step 5, the overall matching deviation β of the longitude x and the overall matching deviation of latitude β y Perform fusion calculations and conduct overall adaptability analysis of the nodes based on the fusion results.

[0028] Preferably, the geophysical field is a gravity field, a geomagnetic field or a topography.

[0029] Beneficial effects:

[0030] (1) The present invention provides a method for analyzing the adaptability of geophysical field matching navigation based on deviation estimation. It uses the knowledge of probability theory and calculus to quantitatively estimate the matching deviation of geophysical field matching navigation, and uses the matching deviation to measure the adaptability, so that the matching effect can be quantified. It has a clear physical meaning and is easy to set the threshold. It overcomes the shortcomings of traditional methods that the threshold is difficult to determine and cannot quantitatively describe the matching effect.

[0031] (2) When quantifying adaptability, the present invention regards it as the ability of the system that is related to the search area, observation accuracy (standard deviation σ), geophysical field background map, and matching algorithm, rather than just the characteristics of the geophysical field background map, which can measure the matching effect more comprehensively and accurately.

[0032] (3) The present invention can independently estimate the adaptability of longitude and latitude, and more fully explore the matching area.

[0033] (4) In a preferred embodiment, the range of the particle filter is used as the window for the adaptability analysis. The adaptability analysis window and the range of the particle filter are consistent. There will be no adaptability estimation error due to inconsistent window ranges, and the adaptability analysis is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention provides a flow chart of a method for analyzing the adaptability of geophysical field matching navigation based on deviation estimation. DETAILED DESCRIPTION

[0035] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0036] In view of the fact that underwater gravity matching navigation is an important underwater passive navigation method and the gravity field information is stable, the present invention is explained by underwater gravity matching navigation. However, the present invention is also applicable to other geophysical field matching navigation methods such as terrain matching navigation and geomagnetic matching navigation, and is also applicable to non-underwater scenes such as land and aviation. Figure 1 A flowchart of a method for analyzing the adaptability of geophysical field matching navigation based on deviation estimation provided by the present invention is given. The method quantifies the adaptability of geophysical field matching navigation by estimating the longitude and latitude matching deviation. The process is as follows:

[0037] Step 1: Use the range of particle filtering as the window S for adaptability analysis ear According to the accuracy and computational complexity, we choose the appropriate latitude and longitude step size. earThe advantage is that the window of the adaptability analysis is consistent with the range of the particle filter, which will not cause adaptability estimation errors due to inconsistent window ranges, and the adaptability analysis is more accurate.

[0038] Step 2: Take the gravity anomaly value as the observation value, assume that the overall observation error of the gravity anomaly is a Gaussian error, the standard deviation is σ, input the gravity anomaly background map and the value of σ, and determine the geophysical field characteristic value of each node. Its advantage is that it takes into account the impact of gravity anomaly observation noise on adaptability and performs quantitative calculations.

[0039] Step 3: According to the prior probability distribution type of the real position and the matching algorithm to be used, the longitude matching deviation model and the latitude matching deviation model of the geophysical field matching are determined respectively.

[0040] The matching algorithm selected in this embodiment is particle filtering or its derivative algorithm, and it is assumed that the prior probability distribution of the real position is S ear The latitude and longitude matching deviation of gravity matching navigation is estimated by the following formula:

[0041]

[0042] Among them, β x For S ear The overall matching bias estimate for longitude within β y For S ear The overall matching deviation estimate for the latitude within For S ear Any node in The sampling value of the gravity anomaly background map at For S ear Any node in Gravity anomaly background map sampling value at node YesS ear The possible real positions within need to be traversed; Is a node The advantage is that it gives the theoretical positioning deviation of gravity matching navigation based on particle filter algorithm.

[0043] Step 4: Substitute the distribution parameters corresponding to the prior probability distribution type and the geophysical field characteristic values ​​of each node into the model determined in step 3 to obtain the estimated overall longitude matching deviation β x and the overall matching deviation of latitude β y .

[0044] Step 5: Take the estimated β x and β yThey are used as quantitative indicators of the longitude and latitude adaptability of gravity matching navigation. The advantage is that the adaptability can be quantified and the physical meaning (matching deviation) is clear; and because β x and β y They can be calculated separately, their adaptability can be distinguished, and criteria can be set separately, such as adaptation criteria based on thresholds, so that they can better adapt to the directional differences in the gravity field and fully explore the matching areas.

[0045] In practice, we can also match the estimated longitude with an overall deviation β x and the overall matching deviation of latitude β y Perform fusion calculations and conduct overall adaptability analysis on corresponding nodes based on the fusion results.

[0046] The following gives β x and β y The derivation process:

[0047] Assume that the measured value of gravity anomaly is g me , it is easy to know, g me is a random variable, denoted by G. Assume that the node is the true position, and the probability density function of G is represents a normal distribution with a standard deviation of σ and an expectation of Indicates that when gravity anomaly observation is performed, the node exist is the observation weight under the assumption of the true position, denoted as random variable P1. It is denoted as P1 = g(G), where g represents the functional relationship between P1 and G. The probability density function of P1 is E(P1) represents the node exist is the weight expectation under the assumption of the true position. Since the inverse function of function g does not necessarily exist, The expression of cannot be obtained directly, so it is necessary to find an equivalent form of the integral. Since g is not necessarily a monotonic function, without loss of generality, assume that the interval {g(G)|y≤g(G)<y+dy} on the range of the function P1=g(G) corresponds to the interval {G|x1≤G<x1+dx1}∪{G|x2≤G<x2+dx2}∪......∪{G|x n ≤G<x n +dx n},{G|x1≤G<x1+dx1},…,{G|x n ≤G<x n +dx n} and so on. Each subinterval does not intersect with each other. There is P(y≤g(G)<y+dy)=f G (x1)dx1+fG (x2)dx2+……+f G (x n )dx n .

[0048] And because y=g(x1)=g(x2)=……=g(x n ),so From the meaning of differential and integral, we can know Right now because It is arbitrary, Respectively expressed in is an estimate of the longitude and latitude matching deviation under the assumption of the true location. It may be any position in the window. Assume that the prior probability distribution of the real position is S ear The uniform distribution within

[0049]

[0050] Among them, β x For S ear The overall matching bias estimate for longitude within β y For S ear The overall matching bias estimate for latitude within .

[0051] Although only the gravity anomaly is observed here, and the prior probability distribution of the true position is assumed to be S ear If other observations are added or the prior probability distribution of the real position is changed, the formula can be deformed according to the principle of formula derivation. The principle of formula derivation is summarized as follows:

[0052] Step (1) uses the position of the spacecraft as an estimate;

[0053] Step (2) determining the prior probability distribution of the position according to the prior conditions;

[0054] Step (3) The observation result of the geophysical field characteristic value is determined by the geophysical field characteristics at the position of the spacecraft and is affected by the observation error. According to the characteristics of the observation error and the geophysical field background map, the conditional probability distribution of the geophysical field characteristic value observation quantity to the spacecraft position is obtained;

[0055] Step (4) assumes the true position of a spacecraft (referred to as condition 1), and obtains an estimate of the posterior probability distribution of the spacecraft position under condition 1 based on the conditional probability distribution of the spacecraft position based on the characteristic value observation of the geophysical field, the selected matching algorithm (essentially estimating the selected model), and the observation error characteristics;

[0056] Step (5) obtains an estimated value of the position under condition 1 based on the posterior probability distribution of the position of the aircraft under condition 1 in step (4). Compares the estimated true position to find the matching deviation of the estimate under condition 1;

[0057] Step (6) Since the estimated matching deviation obtained in step (5) is based on a certain assumed real position, all possible real positions are traversed, and steps (4) to (5) are repeated. Combined with the prior probability distribution of the real position, an estimate of the overall matching deviation within the search range is obtained.

[0058] The above specific embodiments only describe the design principle of the present invention. The shapes and names of the components in the description may be different and are not limited. Therefore, those skilled in the art in the field of the present invention may modify or replace the technical solutions recorded in the above embodiments; and these modifications and replacements do not deviate from the creative purpose and technical solutions of the present invention and should all fall within the protection scope of the present invention.

Claims

1. A geophysical field matching navigation adaptability analysis method based on deviation estimation, characterized in that: The method includes: Step 1: In the given adaptability analysis window S ear Perform node division inside to obtain i×j nodes; Step 2: Input the geophysical field background map and determine the geophysical field characteristic value of each node; Step 3: According to the prior probability distribution type of the real position and the matching algorithm to be used, the longitude matching deviation model and the latitude matching deviation model of the geophysical field matching are determined respectively; Step 4: Substitute the distribution parameters corresponding to the prior probability distribution type and the geophysical field characteristic values ​​of each node into the model determined in step 3 to obtain the estimated overall longitude matching deviation β x and the overall matching deviation of latitude β y ; Step 5: Use the estimated longitude overall matching deviation β x To measure the longitude adaptability of geophysical field matching navigation, the estimated latitude overall matching deviation β is used y Measure the latitude adaptability of geophysical field matching navigation and implement adaptability analysis.

2. A method for analyzing the suitability of geophysical field matching navigation based on deviation estimation according to claim 1, characterized in that: In step 3, according to the prior probability distribution type of the real position and the matching algorithm to be used, the overall longitude matching deviation model and the overall latitude matching deviation model of the geophysical field matching are respectively determined as follows: Step 31: Taking the position of the spacecraft as an estimate; Step 32: Determine the prior probability distribution of the position according to the prior conditions; Step 33: The observation result of the characteristic value of the geophysical field is determined by the characteristics of the geophysical field at the position of the spacecraft and is affected by the observation error; according to the characteristics of the observation error and the geophysical field background map, the conditional probability distribution of the observation value of the characteristic value of the geophysical field to the position of the spacecraft is obtained; Step 34: Assume a true position of a spacecraft as condition 1, and obtain an estimate of the posterior probability distribution of the spacecraft position under condition 1 based on the conditional probability distribution of the geophysical field eigenvalue observations on the spacecraft position, the selected matching algorithm, and the observation error characteristics; Step 35: Based on the posterior probability distribution estimation of the aircraft position under condition 1 in step 34, obtain the estimated value of the position under condition 1; compare with the assumed true position to obtain the matching deviation of the estimate under condition 1; Step 36: Traverse all possible true positions, repeat steps 34 and 35, and combine the prior probability distribution of the true positions to obtain an estimate of the overall matching deviation within the search range.

3. The method for analyzing the suitability of geophysical field matching navigation based on deviation estimation according to claim 2, characterized in that: The matching algorithm is based on Bayesian estimation.

4. The method for analyzing the suitability of geophysical field matching navigation based on deviation estimation according to claim 2, characterized in that: The prior probability distribution type is the adaptability analysis window S ear The uniform distribution within the geophysical field is σ, and the observation standard deviation of the characteristic value of the geophysical field is σ; the matching algorithm adopts particle filtering or its derivative algorithm; then the overall longitude matching deviation model and latitude matching deviation model of the geophysical field matching are: Among them, β x The adaptability analysis window S ear The overall matching bias estimate for longitude within β y The adaptability analysis window S ear The overall matching deviation estimate for the latitude within The adaptability analysis window S ear Any node in The characteristic value of the geophysical field at The adaptability analysis window S ear Any node in The characteristic value of the geophysical field at the node is the adaptability analysis window S ear The possible real positions within need to be traversed. Is a node The characteristic values ​​of the geophysical field at .

5. The method for analyzing the suitability of geophysical field matching navigation based on deviation estimation according to claim 4, characterized in that: The range of particle filtering is used as the adaptability analysis window S ear .

6. The method for analyzing the suitability of geophysical field matching navigation based on deviation estimation according to claim 1, characterized in that: Overall matching deviation β for longitude x and the overall matching deviation of latitude β y Criteria are set respectively, and suitability analysis of longitude and latitude is performed based on the criteria respectively.

7. The method for analyzing the suitability of geophysical field matching navigation based on deviation estimation according to claim 1, characterized in that: In step 5, the overall matching deviation β of longitude x and the overall matching deviation of latitude β y Perform fusion calculations and conduct overall adaptability analysis of the nodes based on the fusion results.

8. The method for analyzing the suitability of geophysical field matching navigation based on deviation estimation according to claim 1, characterized in that: The geophysical field is a gravity field, a geomagnetic field or a topography.

Images