CN102419181B - Autonomous non-overshoot state switching method of ship inertial navigation system - Google Patents

Abstract

The invention discloses an autonomous non-overshoot state switching method of a ship inertial navigation system, comprising the following steps of: determining the damping ratio of a correction link; determining the time domain parameter during the calibration process; determining the cut-off frequency during the correction link; determining the system bandwidth; determining two handover frequencies during the correction link; determining a low-frequency band during the correction link; determining a high-frequency band during the correction link; determining the convergence frequency band of the correction link; determining the transmission function during the correction link; determining the switching time; determine the switching step length; determining the velocity variable before and after the correction; acquiring acceleration and angular velocity of the inertial device output; compensating for the inertia device output according to the error source of the inertial device; integrating the acceleration information to obtain the speed; acquiring a velocity correction value; acquiring speed after the correction; acquiring angular velocity information after the correction and feeding back by the Shura loop; and integrating the speed after the correction to obtain the position after the correction. By the adoption of the method provided by the invention, overshoot errors generated during the state switching process can be inhibited without depending on the external speed.

Description

Autonomous non-overshoot state switching method of ship inertial navigation system

Technical field

The present invention relates to inertial navigation technology field, refer to particularly a kind of autonomous non-overshoot state switching method of ship inertial navigation system.

Technical background

The horizontal circuit essence of inertial navigation system is the second-order system of a neutrality, and system is under error source (gyroscopic drift, accelerometer bias etc.) effect, and output presents periodic swinging trend.In order to suppress the oscillatory error of system, a kind of effective solution adds correction link exactly in system circuit, changes the characteristic root of system circuit, makes loop have damping action, with the oscillatory error that decays and cause due to error source.Known according to control theory, after adding correction link, make inertial navigation system precision be subject to carrier acceleration action strong, therefore at boats and ships, during in maneuvering condition, need to make inertial navigation system be switched to without correcting state by correcting state.Therefore boats and ships, in navigation process, can frequently be adjusted according to the motion state of carrier the duty of inertial navigation system.When system switches to correcting state without correcting state, system circuit is undergone mutation because of state after adding damping link, and this can cause system when carrying out " without being corrected to correction " state switching, to cause overshoot error.Take system level correction as example, when carrying out switching without the state that is corrected to level correction, system will be in 1～2 Schuler cycle (Schuler cycle is 84.4 minutes) completion status transient process, therefore the overshoot error occurring in this section of process will make the output information of inertial navigation system unavailable, has affected greatly the navigation safety of inertial navigation system precision and boats and ships.

Correlative study (Cheng Jianhua, Zhao Lin, Song Juncai etc. the applied research of automatic compensatory technique in Platform Inertial Navigation System state switches) from the angle of " transient equilibrium ", explained at present and the reason of overshoot error proposed to utilize outer speed to carry out overshoot compensation.But this compensation way depends on outer degree of testing the speed, and may remain not compensating error, and this remains not compensating error all has considerable influence to the navigation safety of inertial navigation system precision and boats and ships.

Summary of the invention

Object of the present invention will provide a kind of autonomous non-overshoot state switching method of ship inertial navigation system exactly, and the method can realize in the situation that not relying on extraneous speed, thoroughly suppresses to switch because of state the overshoot error producing in (without being corrected to correction) process.

For achieving the above object, the designed a kind of autonomous non-overshoot state switching method of ship inertial navigation system of the present invention, is characterized in that, it comprises the steps:

Step S 11: according to ship motion state, from suppressing systematic error aspect and reducing correction link, two aspects that affect of system circuit are considered, determined the dampingratioζ that is suitable for Vessel's Description;

Step S12: determine the time domain parameter of correction link, described time domain parameter comprises resonance peak M _rwith adjusting time t _s,

According to the relational expression of second-order system resonance peak and damping ratio

$M_r=\frac{1}{2\mathrm{\ζ}\sqrt{1-{\mathrm{\ζ}}^2}}---\left(1\right)$

By the dampingratioζ substitution obtaining in step S11 wherein, draw the resonance peak M of system _r; Meanwhile, set the adjusting time t of trimming process _sfor set-point A;

Step S13: determine the cutoff frequency of trimming process expectation,

According to the relational expression of high order system frequency-domain and time-domain index

$t_s=\frac{\mathrm{K\π}}{{\mathrm{\ω}}_c}---\left(2\right)$

In formula: K=2+1.5 (M _r-1)+2.5 (M _r-1) ², t _sfor regulating time set-point A in step S12; M _rfor resonance peak M in step S12 _r;

Obtain the cutoff frequency ω of trimming process expectation _c;

Step S14: the system bandwidth of determining correction link;

According to automatic control system theory, obtain the relational expression of system bandwidth and maximum Phase margin

$\frac{1}{\sin \mathrm{\γ}}=\frac{H+1}{H-1}---\left(3\right)$

In formula: the system bandwidth that H is correction link, γ is Phase margin, wherein, Phase margin γ is setting value B, Phase margin γ substitution formula (3) is obtained to the value of the system bandwidth H of correction link;

Step S15: the two handing-over frequencies of determining correction link;

According to the angular frequency of maximum phase angle _mrelational expression

${\mathrm{\ω}}_m=\sqrt{{\mathrm{\ω}}_2{\mathrm{\ω}}_3}---\left(4\right)$

The system bandwidth relational expression of correction link

H＝ω ₂/ω ₃ (5)

In addition, for making system obtain large as far as possible Phase margin, the maximum phase angle margin angle frequency of selection correction link approaches the cutoff frequency of system, i.e. ω _m≈ ω _c(6)

According to above-mentioned formula (4), formula (5), formula (6), can obtain two handing-over frequencies omega ₂and ω ₃;

Step S16: the low-frequency range of determining correction link;

After proofreading and correct system adopt with without the same low-frequency range of corrective system;

Step S17: the high band of determining correction link;

After proofreading and correct system adopt with without the same high band of corrective system;

Step S18: the linking frequency range of determining correction link;

According to formula ω ₄=H * ω ₃(7)

In formula: the system bandwidth that H is correction link, ω ₃for the handing-over frequency in step S15, according to formula (7), obtain the linking frequency range ω of correction link ₄.

Step S19: according to S15, S18 determines that the transport function of correction link is following formula

$G\left(s\right)=\frac{(1+s/{\mathrm{\ω}}_2)(1+s/{\mathrm{\ω}}_4)}{{(1+s/{\mathrm{\ω}}_3)}^2}---\left(8\right)$

Wherein s is differentiating operator;

Step S20: when step S11 carries out, determine that system transfers by nothing correction the transit time that correcting state switches to, described system is 10～20 minutes preset times by the transit time that transfers correcting state switching without correction to;

Step S21: according to the handing-over frequencies omega in correction link transport function definite in S19 ₂, ω ₃, be connected frequencies omega ₄and the handing-over frequencies omega of determining system transit time of the switching of the state in step S20 ₂, ω ₃, be connected frequencies omega ₄switching step-length; The concrete step-length of switching is according to formula

obtain, wherein, correcting state parameter is the parameter of the transport function of definite applicable current motion state, handing-over frequencies omega ₂, ω ₃with linking frequencies omega ₄, current plan correcting state parameter is the parameter of the transport function of inertial navigation system before correction, handing-over frequencies omega ₂, ω ₃with linking frequencies omega ₄, switching the excessive time is 10～20 minutes.

Step S22: the speed differential equation of the transport function of utilizing correction link in step S19 before and after the formula in step S19 (8) is carried out can obtaining after anti-Laplace transform proofreading and correct;

Speed before definition boats and ships are proofreaied and correct is v, and the speed after correction is v '.Formula (8) is transport function between the two, is second order differential equation.For formula (8) is converted, defining two intermediate variables is u ₁, u ₂, have:

$u_1=\frac{({\mathrm{\ω}}_4-{\mathrm{\ω}}_3)v}{s+{\mathrm{\ω}}_3}$

(9)

$u_2=\frac{({\mathrm{\ω}}_2-{\mathrm{\ω}}_3)}{s+{\mathrm{\ω}}_3}(v+u_1)$

Formula (8) is carried out to corresponding deformation, can obtain following differential equation group.

${\stackrel{\·}{u}}_1+{\mathrm{\ω}}_3{u}_1=\left({\mathrm{\ω}}_4-{\mathrm{\ω}}_3\right)v$

${\stackrel{\·}{u}}_2+{\mathrm{\ω}}_3{u}_2=\left({\mathrm{\ω}}_2-{\mathrm{\ω}}_3\right)v+({\mathrm{\ω}}_2-{\mathrm{\ω}}_3)u_1---\left(10\right)$

v′＝q(v+u ₁+u ₂)

for the constant in equation conversion.Above-mentioned system of equations has been determined the length velocity relation before and after proofreading and correct;

Obtain after the speed differential equation, according to frequency parameter definite in step S21, switch step-length, be i.e. ω during each velocity correction ₂, ω ₃, ω ₄change amount, thereby the velocity variable before and after determine proofreading and correct according to formula (10);

Step S31: obtain angular velocity and the acceleration information of inertia device output, described inertia device is gyro and accelerometer;

Step S32: angular velocity and the acceleration information of inertia device output are compensated according to the error source of inertia device;

Step S33: the acceleration information of accelerometer output is carried out to integration and obtain velocity information;

Step S34: according to the velocity variable before and after proofreading and correct in step S22, and the speed before the correction in step S33 obtains velocity correction amount;

Step S35: measure the rear speed of proofreading and correct according to the speed before proofreading and correct in step S33 and the velocity correction in step S34;

Step S36: utilize velocity information after the correction in step S35, according to INS model, obtain proofreading and correct rear angular velocity information, after this correction angular velocity information by shura circuit feedback to the navigation calculation of proceeding step S33～step S38 after step S32;

Step S37: speed after the correction in step S35 is carried out to integration;

Step S38: the positional information after being proofreaied and correct completes whole handoff procedure.

Ship motion state in above-mentioned steps S11 is frequency and the amplitude of speed, acceleration, oscillating motion.

Dampingratioζ in above-mentioned steps S11 is 0～1.

Dampingratioζ in above-mentioned steps S11 is 0.5.

The adjusting time t of trimming process in above-mentioned steps S12 _sit is 20～40 minutes.

In above-mentioned steps S14, Phase margin γ is 45～60 degree.

In above-mentioned steps S14, Phase margin γ is 45 degree.

The present invention is first from the control model in inertial navigation system loop, the Phase margin, open loop amplitude-frequency rate of curve, cutoff frequency, corner frequency that the indexs such as the rise time on time domain specification, adjusting time are converted into response with bandwidth, be connected the frequency-domain index such as frequency range, the open loop amplitude versus frequency characte of drawing system expectation, provides the parameter of the corrective network of inertial navigation system, the method for designing of the analytic expression of structure.By the method, make the corrective network of design meet system stability requirement, the gain of high and low frequency section guarantees that system has good noise inhibiting ability, and system time domain index meets expection.Design the damping correction link with different damping ratio, at inertial navigation system, carry out state while switching, thereby the parameter that continuously changes correction link changes system damping ratio, reduces the overshoot error causing because of loop state sudden change.

The control model of state switching method provided by the invention based on inertial navigation system loop, realization does not rely on external information, the structure, parameter that only changes system compensation link transport function with and variation pattern, having realized inertial navigation system switches at the steady non-overshoot that carries out " nothing correction---correction " state, solved the information disabled problem in the transient process that inertial navigation system switches, generally speaking principal feature of the present invention and advantage are as follows:

(1) overcome traditional trial method and carried out the blindness of corrective network design and tentative.The design of inertial navigation system will be based on two cardinal rules: first will make the correction link of introducing have larger damping ratio, to suppress the oscillatory error of system within a short period of time, second will reduce the impact on system of the correction link introduced, and this requires system should have less damping ratio.Traditional corrective network method for designing is the damping link damping ratio of introducing to be set on 0.5 basis, to carry out the trial of network parameter according to system feature, utilizes the network of attempting to carry out system experimentation, according to experiment effect, is further adjusting relevant parameter.This method designed system damping ratio is relatively fixing, only in applicable as very little in boats and ships acceleration situation.In addition, the method has very large exploratory, can not guarantee the optimization of corrective network parameter.Method of the present invention is directly converted into frequency-domain index by index on the time domain specification in inertial navigation system loop, the open loop amplitude versus frequency characte of drawing system expectation.The method can be resolved the Optimal Parameters and the structure that obtain correction link according to the damping ratio of system expectation, has stronger specific aim and adaptability.

(2) suppress system and carried out the error that " without proofreading and correct-proofreading and correct " state switches.Classic method is when switching, and return transfer function is undergone mutation, and system changes progressive steady state (SS) into by neutrality, makes system in state conversion process, occur overshoot error.This error has even surpassed system in the error without timing, causes inertial navigation system output information unavailable in stateful switchover process, has affected the continuity of inertial navigation system, and threatens the navigation safety on naval vessel.The present invention proposes in inertial system state handoff procedure, and the parameter of continuous change correction link makes system by the corrective network to expectation damping ratio without the progressive smooth transition of correction.Due to the progressive change of system state, system transient process is steady, non-overshoot error, and system output information is available continuously.System enters after correcting state, and oscillatory error is decayed.

(3) do not need to rely on oracle, realized autonomous, full remuneration that system state is switched.Turntable provided by the invention switches overshoot method based on to the modeling in inertial navigation system loop and analysis, by the correction link of reasonable change and design system, the non-overshoot that the system self information of utilization is realized inertial navigation duty switches, thoroughly the overshoot error of bucking-out system.

Accompanying drawing explanation

Fig. 1 is schematic diagram of the present invention;

Fig. 2 is the contrast test the result of state switching method of the present invention and classic method.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail:

A kind of autonomous non-overshoot state switching method of ship inertial navigation system as described in Figure 1, is characterized in that, it comprises the steps:

Step S11: from suppressing systematic error aspect and reducing correction link, two aspects that affect of system circuit are considered according to ship motion state (frequency of speed, acceleration, oscillating motion, amplitude), determine the dampingratioζ that is suitable for Vessel's Description, dampingratioζ is 0～1, is preferably 0.5;

Step S12: determine the time domain parameter of correction link, described time domain parameter comprises resonance peak M _rwith adjusting time t _s,

According to the relational expression of second-order system resonance peak and damping ratio

$M_r=\frac{1}{2\mathrm{\ζ}\sqrt{1-{\mathrm{\ζ}}^2}}---\left(1\right)$

By the dampingratioζ substitution obtaining in step S11 wherein, draw the resonance peak M of system _r; Meanwhile, set the adjusting time t of trimming process _sit is 20～40 minutes;

In step S12, when the correction link of expectation has ζ=0.5 damping ratio, the correction link that carries out system state switching for example designs.The resonance peak M of system now _r=1.1547.System produces the continuous oscillation of Schuler cycle under constant error effect, and the rise time of response is 1/4 Schuler cycle.For obtaining good dynamic property, the adjusting time that can initialization system is 0.5 Schuler cycle, regulates time t _s=2532s

Step S13: determine the cutoff frequency of trimming process expectation,

According to the relational expression of high order system frequency-domain and time-domain index

$t_s=\frac{\mathrm{K\π}}{{\mathrm{\ω}}_c}---\left(2\right)$

In formula: K=2+1.5 (M _r-1)+2.5(M _r-1) ², t _sfor regulating time t in step S12 _s=2532s; M _rfor resonance peak M in step S12 _r=1.1547;

Obtain the cutoff frequency ω of trimming process expectation _c=0.0028rad/s;

Step S 14: the system bandwidth of determining correction link;

According to automatic control system theory, obtain the relational expression of system bandwidth and maximum Phase margin

$\frac{1}{\sin \mathrm{\γ}}=\frac{H+1}{H-1}---\left(3\right)$

In formula: the system bandwidth that H is correction link, γ is Phase margin, wherein, Phase margin γ is 45～60 degree, is preferably 45 degree, Phase margin γ substitution formula (3) is obtained to the value H=13.9282 of the system bandwidth H of correction link;

Step S15: the two handing-over frequencies of determining correction link;

According to the angular frequency of maximum phase angle _mrelational expression

${\mathrm{\ω}}_m=\sqrt{{\mathrm{\ω}}_2{\mathrm{\ω}}_3}---\left(4\right)$

The system bandwidth relational expression of correction link

H＝ω ₂/ω ₃ (5)

In addition, for making system obtain large as far as possible Phase margin, the maximum phase angle margin angle frequency of selection correction link approaches the cutoff frequency of system, i.e. ω _m≈ ω _c(6)

According to above-mentioned formula (4), formula (5), formula (6), can obtain two handing-over frequencies omega ₂and ω ₃; According to above formula, can obtain two handing-over frequencies omega ₂=7.5025 * 10 ^-4rad/s, ω ₃=1.04 * 10 ^-2rad/s

Step S16: the low-frequency range of determining correction link;

After proofreading and correct system adopt with without the same low-frequency range of corrective system;

Step S17: the high band of determining correction link;

After proofreading and correct system adopt with without the same high band of corrective system;

Step S18: the linking frequency range of determining correction link;

According to formula ω ₄=H * ω ₃(7)

In formula: the system bandwidth that H is correction link, ω ₃for the handing-over frequency in step S15, according to formula (7), obtain the linking frequency range ω of correction link ₄, according to above formula, can obtain ω ₄=H * ω ₃=0.1449.

Step S19: according to S15, S18 determines that the transport function of correction link is following formula (8)

$G\left(s\right)=\frac{(1+s/{\mathrm{\ω}}_2)(1+s/{\mathrm{\ω}}_4)}{{(1+s/{\mathrm{\ω}}_3)}^2}---\left(8\right)$

Above each corner frequency substitution is obtained:

$G\left(s\right)=\frac{(1+7.5025\×{10}^{-4})(s+0.1449)}{{(s+1.04\×{10}^{-2})}^2}$

Step S20: when step S11 carries out, determine that system transfers by nothing correction the transit time that correcting state switches to, described system is 10～20 minutes by the transit time that transfers correcting state switching without correction to;

Step S21: according to the handing-over frequencies omega in correction link transport function definite in S 19 ₂, ω ₃, be connected frequencies omega ₄and the state in step S20 switch 10～20 minutes transit times definite system handing-over frequencies omega ₂, ω ₃, be connected frequencies omega ₄switching step-length; The concrete step-length of switching is according to formula

obtain, wherein, correcting state parameter is the parameter of the transport function of definite applicable current motion state, handing-over frequencies omega ₂, _{ω 3}with linking frequencies omega ₄, current plan correcting state parameter is the parameter of the transport function of inertial navigation system before correction, handing-over frequencies omega ₂, ω ₃with linking frequencies omega ₄, switching the excessive time is 10～20 minutes.

Step S22: the speed differential equation of the transport function of utilizing correction link in step S 19 before and after the formula in step S 19 (8) is carried out can obtaining after anti-Laplace transform proofreading and correct;

Speed before definition boats and ships are proofreaied and correct is v, and the speed after correction is v '.Formula (8) is transport function between the two, is second order differential equation.For formula (8) is converted, defining two intermediate variables is u ₁, u ₂, have:

${\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HDA0000089760830000021.png"\; state="\{\{state\}\}">u</figure-callout>}}_1=\frac{({\mathrm{\&omega;}}_4-{\mathrm{\&omega;}}_3)v}{s+{\mathrm{\&omega;}}_3}$

(9)

$u_2=\frac{({\mathrm{\&omega;}}_2-{\mathrm{\&omega;}}_3)}{s+{\mathrm{\&omega;}}_3}(v+u_1)$

Formula (8) is carried out to corresponding deformation, can obtain following differential equation group.

${\stackrel{\&CenterDot;}{u}}_1+{\mathrm{\&omega;}}_3{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HDA0000089760830000021.png"\; state="\{\{state\}\}">u</figure-callout>}}_1=\left({\mathrm{\&omega;}}_4-{\mathrm{\&omega;}}_3\right)v$

${\stackrel{\&CenterDot;}{u}}_2+{\mathrm{\&omega;}}_3{u}_2=\left({\mathrm{\&omega;}}_2-{\mathrm{\&omega;}}_3\right)v+({\mathrm{\&omega;}}_2-{\mathrm{\&omega;}}_3)u_1---\left(10\right)$

v′＝q(v+u ₁+u ₂)

for the constant in equation conversion.Above-mentioned system of equations has been determined the length velocity relation before and after proofreading and correct, wherein, with

respectively intermediate variable u ₁and u ₂differential;

Obtain after the speed differential equation, according to frequency parameter definite in step S21, switch step-length, be i.e. ω during each velocity correction ₂, ω ₃, ω ₄change amount, thereby the velocity variable before and after determine proofreading and correct according to formula (10);

Step S31: obtain angular velocity and the acceleration information of inertia device output, described inertia device is gyro and accelerometer;

Step S32: angular velocity and the acceleration information of inertia device output are compensated according to the error source of inertia device; Wherein, the error source of inertia device is an inherent error in existing inertia system, the compensation of step S32 for this inherent error is carried out, the prior art that it is known to the skilled person;

Step S33: the acceleration information of accelerometer output is carried out to integration and obtain velocity information;

Step S34: according to the velocity variable before and after proofreading and correct in step S22, and the speed before the correction in step S33 obtains velocity correction amount;

Step S35: measure the rear speed of proofreading and correct according to the speed before proofreading and correct in step S33 and the velocity correction in step S34;

Step S36: utilize in step S35 the velocity information after proofreading and correct, according to INS model, obtain proofreading and correct rear angular velocity information, this corrections afterwards angular velocity information by shura circuit feedback to the navigation calculation of proceeding step S33～step S38 after step S32;

Step S37: speed after the correction in step S35 is carried out to integration;

Step S38: the positional information after being proofreaied and correct completes whole handoff procedure.

In the step S 14 of technique scheme, the process that draws of formula (3) is:

In order to make system have better stability margin under same bandwidth condition, neutrality system is after overcorrect, and Mid Frequency should have the transport function of following form:

$G\left(s\right)=\frac{{\mathrm{\&omega;}}_s^2(1+s/{\mathrm{\&omega;}}_2)}{s^2(1+s/{\mathrm{\&omega;}}_3)}---\left(9\right)$

In formula: ω ₂for the corner frequency before cutoff frequency, make Amplitude Frequency Characteristic increase 20dB/dec slope, ω ₃for the corner frequency after cutoff frequency, choose reasonable ω ₃can determine system bandwidth.

In formula (9), the phase angle γ (ω) of transport function is:

$\mathrm{\&gamma;}\left(\mathrm{\&omega;}\right)=\mathrm{acrtg}\frac{\mathrm{\&omega;}}{{\mathrm{\&omega;}}_2}-\mathrm{acrtg}\frac{\mathrm{\&omega;}}{{\mathrm{\&omega;}}_3}---\left(10\right)$

The angular frequency of the maximum phase angle of formula (10) generation system _mfor:

${\mathrm{\&omega;}}_m=\sqrt{{\mathrm{\&omega;}}_2{\mathrm{\&omega;}}_3}---\left(11\right)$

Formula (11) substitution formula (10) is obtained

$\sin \mathrm{\&gamma;}\left(\mathrm{\&omega;}\right)=\frac{{\mathrm{\&omega;}}_3-{\mathrm{\&omega;}}_2}{{\mathrm{\&omega;}}_3+{\mathrm{\&omega;}}_2}---\left(12\right)$

According to definitions of bandwidth, intermediate-frequency bandwidth H=ω ₂/ ω ₃, its substitution formula (12) is obtained:

$\frac{1}{\sin \mathrm{\&gamma;}\left({\mathrm{\&omega;}}_m\right)}=\frac{H+1}{H-1}---\left(12\right)$

For making system obtain large as far as possible Phase margin, select the maximum phase angle margin angle frequency of correction link to approach the cutoff frequency of system, can think ω _m≈ ω _c, by formula (12), can be obtained: $\frac{1}{\sin \mathrm{\&gamma;}}=\frac{H+1}{H-1}.$

Concrete effect of the present invention as shown in Figure 2.

The content that this instructions is not described in detail belongs to the known prior art of professional and technical personnel in the field.

Claims (6)

1. an autonomous non-overshoot state switching method of ship inertial navigation system, is characterized in that, it comprises the steps:

Step S11: from suppressing systematic error aspect and reducing correction link, two aspects that affect of system circuit are considered according to ship motion state, determine the dampingratioζ that is suitable for Vessel's Description, ship motion state is speed, acceleration, oscillating motion frequency and amplitude;

Step S12: determine the time domain parameter of correction link, described time domain parameter comprises resonance peak M _rwith adjusting time t _s,

According to the relational expression of second-order system resonance peak and damping ratio

$M_r=\frac{1}{2\mathrm{\&zeta;}\sqrt{1-{\mathrm{\&zeta;}}^2}}---\left(1\right)$

By the dampingratioζ substitution obtaining in step S11 wherein, draw the resonance peak M of system _r; Meanwhile, set the adjusting time t of trimming process _sfor set-point A;

Step S13: determine the cutoff frequency of trimming process expectation,

According to the relational expression of high order system frequency-domain and time-domain index

$t_s=\frac{\mathrm{K\&pi;}}{{\mathrm{\&omega;}}_c}---\left(2\right)$

In formula: K=2+1.5 (M _r-1)+2.5 (M _r-1) ², t _sfor regulating time set-point A in step S12; M _rfor resonance peak M in step S12 _r;

Obtain the cutoff frequency ω of trimming process expectation _c;

Step S14: the system bandwidth of determining correction link;

According to automatic control system theory, obtain the relational expression of system bandwidth and maximum Phase margin

$\frac{1}{\sin \mathrm{\&gamma;}}=\frac{H+1}{H-1}---\left(3\right)$

In formula: the system bandwidth that H is correction link, γ is Phase margin, wherein, Phase margin γ is setting value B, Phase margin γ substitution formula (3) is obtained to the value of the system bandwidth H of correction link;

Step S15: the two handing-over frequencies of determining correction link;

According to the angular frequency of maximum phase angle _mrelational expression

${\mathrm{\&omega;}}_m=\sqrt{{\mathrm{\&omega;}}_2{\mathrm{\&omega;}}_3}---\left(4\right)$

The system bandwidth relational expression of correction link

$H={\mathrm{\&omega;}}_2/{\mathrm{\&omega;}}_3---\left(5\right)$

In addition, for making system obtain large as far as possible Phase margin, the maximum phase angle margin angle frequency of selection correction link approaches the cutoff frequency of system, i.e. ω _m≈ ω _c(6)

According to above-mentioned formula (4), formula (5), formula (6), can obtain two handing-over frequencies omega ₂and ω ₃;

Step S16: the low-frequency range of determining correction link;

After proofreading and correct system adopt with without the same low-frequency range of corrective system;

Step S17: the high band of determining correction link;

After proofreading and correct system adopt with without the same high band of corrective system;

Step S18: the linking frequency range of determining correction link;

According to formula ω ₄=H * ω ₃(7)

In formula: the system bandwidth that H is correction link, ω ₃for the handing-over frequency in step S15, according to formula (7), obtain the linking frequency range ω of correction link ₄;

Step S19: according to S15, S18 determines that the transport function of correction link is following formula

$G\left(s\right)=\frac{(1+s/{\mathrm{\&omega;}}_2)(1+s/{\mathrm{\&omega;}}_4)}{{(1+s/{\mathrm{\&omega;}}_3)}^2}---\left(8\right)$

Wherein s is differentiating operator;

Step S20: when step S11 carries out, determine that system transfers by nothing correction the transit time that correcting state switches to, described system is 10 ~ 20 minutes preset times by the transit time that transfers correcting state switching without correction to;

Step S21: according to the handing-over frequencies omega in correction link transport function definite in S19 ₂, ω ₃, be connected frequencies omega ₄and the handing-over frequencies omega of determining system transit time of the switching of the state in step S20 ₂, ω ₃, be connected frequencies omega ₄switching step-length; The concrete step-length of switching is according to formula

obtain, wherein, correcting state parameter is the parameter of the transport function of definite applicable current motion state, handing-over frequencies omega ₂, ω ₃with linking frequencies omega ₄, current plan correcting state parameter is the parameter of the transport function of inertial navigation system before correction, handing-over frequencies omega ₂, ω ₃with linking frequencies omega ₄, switching the excessive time is 10 ~ 20 minutes;

Step S22: the speed differential equation of the transport function of utilizing correction link in step S19 before and after the formula in step S19 (8) is carried out can obtaining after anti-Laplace transform proofreading and correct;

Speed before definition boats and ships are proofreaied and correct is v, and the speed after correction is v ＇, and formula (8) is transport function between the two, is second order differential equation, and for formula (8) is converted, defining two intermediate variables is u ₁, u ₂, have:

$\begin{array}{c}{u}_1=\frac{({\mathrm{\&omega;}}_4-{\mathrm{\&omega;}}_3)v}{s+{\mathrm{\&omega;}}_3}\\ u_2=\frac{({\mathrm{\&omega;}}_2-{\mathrm{\&omega;}}_3)}{s+{\mathrm{\&omega;}}_3}(v+u_1)\end{array}---\left(9\right)$

Formula (8) is carried out to corresponding deformation, can obtain following differential equation group;

$\begin{array}{c}{\stackrel{\&CenterDot;}{u}}_1+{\mathrm{\&omega;}}_3{u}_1=({\mathrm{\&omega;}}_4-{\mathrm{\&omega;}}_3)v\\ {\stackrel{\&CenterDot;}{u}}_2+{\mathrm{\&omega;}}_3{u}_2=({\mathrm{\&omega;}}_2-{\mathrm{\&omega;}}_3)v+({\mathrm{\&omega;}}_2-{\mathrm{\&omega;}}_3)u_1\\ v^{\&prime;}=q(v+u_1+u_2)\end{array}---\left(10\right)$

, be the constant in equation conversion, above-mentioned system of equations has been determined the length velocity relation before and after proofreading and correct;

Obtain after the speed differential equation, according to frequency parameter definite in step S21, switch step-length, be i.e. ω during each velocity correction ₂, ω ₃, ω ₄change amount, thereby the velocity variable before and after determine proofreading and correct according to formula (10);

Step S31: obtain angular velocity and the acceleration information of inertia device output, described inertia device is gyro and accelerometer;

Step S32: angular velocity and the acceleration information of inertia device output are compensated according to the error source of inertia device;

Step S33: the acceleration information of accelerometer output is carried out to integration and obtain velocity information;

Step S34: according to the velocity variable before and after proofreading and correct in step S22, and the speed before the correction in step S33 obtains velocity correction amount;

Step S35: measure the rear speed of proofreading and correct according to the speed before proofreading and correct in step S33 and the velocity correction in step S34;

Step S36: utilize velocity information after the correction in step S35, according to INS model, obtain proofreading and correct rear angular velocity information, after this correction angular velocity information by shura circuit feedback to the navigation calculation of proceeding step S33 ~ step S38 after step S32;

Step S37: speed after the correction in step S35 is carried out to integration;

Step S38: the positional information after being proofreaied and correct completes whole handoff procedure.

2. autonomous non-overshoot state switching method of ship inertial navigation system according to claim 1, is characterized in that: the dampingratioζ in step S11 is 0 ~ 1.

3. autonomous non-overshoot state switching method of ship inertial navigation system according to claim 2, is characterized in that: the dampingratioζ in step S11 is 0.5.

4. autonomous non-overshoot state switching method of ship inertial navigation system according to claim 1, is characterized in that: the adjusting time t of trimming process in step S12 _sit is 20 ~ 40 minutes.

5. autonomous non-overshoot state switching method of ship inertial navigation system according to claim 1, is characterized in that: in step S14, Phase margin γ is 45 ~ 60 degree.

6. autonomous non-overshoot state switching method of ship inertial navigation system according to claim 5, is characterized in that: in step S14, Phase margin γ is 45 degree.

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