Disclosure of Invention
The invention aims to solve the problem that the reentry track of the hypersonic reentry vehicle has extremely strong unknown maneuver characteristics, provides a maneuver detection method based on model probability matching, according to the method, states of different known maneuver models are distinguished by using maneuver model description matrixes, and hypersonic reentry vehicle real-time maneuver detection is realized by a model probability matching-based method.
The invention aims at realizing the following technical scheme:
a maneuver detection method based on model probability matching, the method comprising the steps of:
analyzing different characteristic parameters of the hypersonic reentry vehicle when maneuver mutation occurs, constructing a maneuver model description matrix according to the characteristic parameters, and determining a maneuver model;
Defining an influence factor according to the maneuver model description matrix, and designing a model matching degree function;
setting threshold values for characteristic parameters of different maneuvering models, and calculating a matching vector of the current system and each preset model by integrating actual characteristic parameters of the current system;
step four, bringing the prior influence factors and the calculated matching vectors into a model matching degree function, and calculating model matching probability;
Calculating a model probability correction sequence according to the probability that different maneuver models preset at the current moment coincide with the real state, and finally correcting a model probability vector;
And step six, judging whether a preset model switching condition is met or not by the model probability vector, if so, performing model switching, and resetting the model probability vector according to a model selection result, and if not, not performing model switching, wherein the maneuver detection result model is used as prior information of the follow-up track forecast.
Further, analyzing the change of different characteristic parameters when the hypersonic reentry aircraft has a maneuver mutation according to task requirements, assuming five maneuver models to be preset, and selecting seven quantities of Δax, Δay, Δaz, A K,ΔAk, Δepsilon and Δeta as model characteristic parameters to describe the five models, wherein Δax is an x-axis acceleration difference value, Δay is a y-axis acceleration difference value, Δaz is a z-axis acceleration difference value, A K is an acceleration direction, ΔA k is an acceleration direction difference value, Δepsilon is a speed sign change and Δeta is an acceleration sign change, so as to obtain a maneuver model matrix G;
Each row in G beta represents a possible model, wherein GB1 corresponds to a non-maneuver model, GB2, GB3, GB4, and GB5 correspond to four common maneuver models, and in practical application, the corresponding maneuver models can be designed according to maneuver characteristics of the aircraft.
Further, in the second step, in order to realize the detection of maneuver, a model matching degree function is defined,
gi(t)=KaxiΒi(Δax)+KayiΒi(Δay)+KaziΒi(Δaz)+KAiΒi(AK)
+KAΔiΒi(ΔAk)+KεiΒi(Δε)+KηiΒi(Δη),i=1...5
Wherein K ji is the influence factor of each parameter in the five models, i=1..5 represents five different models, j=1..7 corresponds to seven different parameters Δax, Δay, Δaz, a K,ΔAk, Δε, Δη, where Δax is the x-axis acceleration difference, Δay is the y-axis acceleration difference, Δaz is the z-axis acceleration difference, a K is the acceleration direction, Δa k is the acceleration direction difference, Δε is the velocity sign change, Δη is the acceleration sign change, and the value of the matching degree function g i (t) of the current system for the five preset models is calculated from the matching vector of each model at the current moment i (t) and the corresponding influence factor K ji.
Further, the method ,Bi(t)=[Βi(Δax),Βi(Δay),Βi(Δaz),Βi(AK),Βi(ΔAk),Βi(Δε),Βi(Δη)]|t.
Further, in the third step, the specific method of the matching vector is as follows:
step three, setting corresponding threshold values for each model characteristic parameter:
Let the threshold vector h= [ H (Δax), H (Δay), H (Δaz), H (a K),H(ΔAk), H (Δε), H (Δη) ];
step three, solving the current system description vector G beta (t):
Comparing the estimated values of all model characteristic parameters with corresponding items in the threshold value vector, taking 0 when the estimated values are smaller than the threshold value, and taking 1 when the estimated values are larger than or equal to the threshold value, so as to obtain corresponding current system description vectors G beta (t), wherein G beta (t) is a seven-dimensional vector with the values of 0 and 1;
Step three, the matching vector BETA i (t) is obtained:
And comparing each row of the G BETA (t) with each row of the G BETA (t) according to the bit, taking 1 when the row is the same and taking 0 when the row is different, and obtaining a matching vector BETA i (t) of the current system and each preset model.
Further, in the fifth step, a model probability vector n= [ p 1p 2 p3 p4 p5] T is defined, the vector represents the probability that five types of models preset at the current moment coincide with a real model, that is, p1 represents the probability that a GB1 model preset at the current moment coincides with the real model, p2 represents the probability that a GB2 model preset at the current moment coincides with the real model, p3 represents the probability that a GB3 model preset at the current moment coincides with the real model, p4 represents the probability that a GB4 model preset at the current moment coincides with the real model, and p5 represents the probability that a GB5 model preset at the current moment coincides with the real model, so as to satisfy Σpi=1, i=1, 2..5;
A probability correction sequence { dp1, dp2, dp3, dp4, dp5}, wherein dp1 represents a correction amount of p1, dp2 represents a correction amount of p2, dp3 represents a correction amount of p3, dp4 represents a correction amount of p4, dp5 represents a correction amount of p5, and the probability correction sequence functions to correct the model probability vector based on the estimation result of each step of simulation.
Further, in the step six, the specific mode of model switching is as follows:
step six, giving an initial value of a model probability vector N, setting a related threshold value and a model switching condition;
Step six, judging the model characteristic parameters after each step of filtering, and calculating a model matching function;
step six, determining the matching degree sequence of the current system and the preset five models according to the size sequence of g i (t);
Setting values of probability correction sequences { dp1, dp2, dp3, dp4, dp5} according to the model matching sequence;
Step six, adding the probability correction sequence to the model probability vector N for correction;
Judging whether a preset model switching condition is met for a filtering algorithm requiring a specific maneuver model, if so, performing model switching, and resetting a model probability vector N according to a model selection result, and if not, not performing model switching;
and seventhly, repeating the process until the filtering is finished.
Compared with the prior art, the invention has the beneficial effects that:
(1) And carrying out mathematical modeling and quantification on the detection of the maneuver characteristic and maneuver mutation of the hypersonic reentry vehicle by introducing a maneuver model description matrix, an influence factor, a model matching degree function, a model matching vector and a model probability vector.
(2) The target actual state quantity is converted into model matching probability through designing a model matching degree function, different maneuver models can be set according to the characteristics of different maneuver mutations, and the hypersonic reentry vehicle has the characteristic of extremely strong unknown maneuver characteristics.
(3) And (3) designing a model switching condition, converting the maneuver detection result into a determined maneuver model or a determined maneuver model probability, and adapting to the requirement of subsequent track forecast.
Detailed Description
The following description of the present invention is provided with reference to the accompanying drawings and examples, but is not limited to the following description, but is intended to cover all modifications and equivalents of the present invention without departing from the spirit and scope of the present invention.
Example 1:
The invention provides a maneuver detection method based on model probability matching, which comprises the steps of introducing a maneuver model description matrix, an influence factor, a model matching degree function, a model matching vector and a model probability vector, carrying out mathematical modeling and quantization on maneuver characteristics and maneuver mutation detection of a hypersonic reentry vehicle, converting a target actual state quantity into model matching probability through a design model matching degree function, and finally obtaining a determined maneuver model or a determined maneuver model probability result by a design model switching condition. The method comprises the following specific steps:
Step 1, analyzing the change of different characteristic parameters when the hypersonic reentry vehicle has maneuver mutation according to task requirements, assuming five maneuver models to be preset, and selecting seven quantities of Deltaax, deltaay, deltaaz, A K,ΔAk, deltaepsilon and Deltaeta as model characteristic parameters to describe the five models, wherein Deltaax is an x-axis acceleration difference value, deltaay is a y-axis acceleration difference value, deltaaz is a z-axis acceleration difference value, A K is an acceleration direction, deltaA k is an acceleration direction difference value, deltaepsilon is a speed sign change and Deltaeta is an acceleration sign change, so that a maneuver model matrix G can be obtained.
Each row of G beta represents one possible class of models.
And 2, defining an influence factor according to the maneuver model description matrix, and designing a model matching degree function. To achieve detection of maneuver, a model matching degree function is defined as follows,
gi(t)=KaxiΒi(Δax)+KayiΒi(Δay)+KaziΒi(Δaz)+KAiΒi(AK)+KAΔiΒi(ΔAk)+KεiΒi(Δε)+KηiΒi(Δη),i=1…5
Where K ji is the influencing factor for each parameter in the five classes of models, i=1..5 represents five different models, j=1..7 corresponds to seven different parameters Δax, Δay, Δaz, a K,ΔAk, Δε, Δη. The value of the matching function g i (t) of the current system to the five types of preset models can be calculated by using the BETA i (t) of each model at the current time and the corresponding influence factor K ji. In the simulation process, K ji is given in advance according to the characteristics of the model, and BETA i (t) is the matching vector of the current system and the ith model at the moment t.
Step 3, setting threshold values for the characteristic parameters of different maneuvering models, calculating the matching vector of the current system and each preset model by integrating the actual characteristic parameters of the current system, and setting Bi(t)=[Βi(Δax),Βi(Δay),Βi(Δaz),Βi(AK),Βi(ΔAk),Βi(Δε),Βi(Δη)]|t.
And 4, bringing the prior influence factors and the calculated matching vectors into a model matching degree function, and calculating the model matching probability.
And 5, calculating a model probability correction sequence according to the probability that different maneuver models preset at the current moment are consistent with the real state, and finally correcting the model probability vector.
A model probability vector n= [ p1 p2 p3 p4 p5] T is defined, and this vector represents the probability that five types of models preset at the current moment coincide with the real model.
A probability correction sequence { dp1, dp2, dp3, dp4, dp5} is defined, and the probability correction sequence functions to correct the model probability vector according to the estimation result of each step of simulation. The values of { dp1, dp2, dp3, dp4, dp5} determine how fast the model is determined. When { dp1, dp2, dp3, dp4, dp5} is too large, it can cause "jitter" in the system.
And 6, judging whether a preset model switching condition is met or not by the model probability vector, if so, performing model switching, and meanwhile resetting the model probability vector according to a model selection result, and if not, not performing model switching, wherein the maneuver detection result model is used as prior information of the follow-up track forecast.
Further, the specific method of matching vectors in step 3 is as follows:
Step 3.1, setting corresponding threshold values for each model characteristic parameter:
Let the threshold vector h= [ H (Δax), H (Δay), H (Δaz), H (a K),H(ΔAk), H (Δε), H (Δη) ].
Step 3.2, obtaining the current system description vector G beta (t):
And comparing the estimated values of all the model characteristic parameters with corresponding items in the threshold value vector, taking 0 when the estimated values are smaller than the threshold value and taking 1 when the estimated values are larger than or equal to the threshold value, and obtaining corresponding current system description vector G beta (t), wherein G beta (t) is a seven-dimensional vector with the values of 0 and 1.
Step 3.3, obtaining a matching vector BETA i (t):
And comparing each row of the G BETA (t) with each row of the G BETA (t) according to the bit, taking 1 when the same row is used, and taking 0 when the same row is used, so as to obtain a matching vector BETA i (t) of the current system and each preset model. For example, when g_beta (t) = [ 1010 100 ], the result of the comparison with the first row of the matrix g_beta is b 1 (t) = [ 010 0011 ].
Further, the specific mode of the step 6 model switching is as follows:
and 6.1, giving an initial value of a model probability vector N, setting a related threshold value and a model switching condition.
And 6.2, judging the model characteristic parameters after each step of filtering, and calculating a model matching function.
And 6.3, determining the matching degree sequence of the current system and the preset five types of models according to the size sequence of g i (t).
And 6.4, setting values of probability correction sequences { dp1, dp2, dp3, dp4 and dp5} according to the model matching sequence.
And 6.5, adding the probability correction sequence to the model probability vector N to correct the model probability vector N.
And 6.6, judging whether a preset model switching condition is met for a filtering algorithm requiring a specific maneuver model, if so, performing model switching, resetting a model probability vector N according to a model selection result, and if not, not performing model switching, and directly taking the maneuver model probability as maneuver detection output for an IMM interactive multi-model filtering algorithm requiring each maneuver model probability.
And 6.7, repeating the process until the filtering is finished.