CN101832775B - Deep ocean work and underwater vehicle combined navigation system and underwater initial alignment method - Google Patents

Abstract

The invention discloses a deep ocean work and underwater vehicle combined navigation system and an underwater initial alignment method. The system comprises a satellite constellation, a differential satellite base station, a satellite buoy system, an underwater navigation transceiver and a boat base data control center. The method is characterized in that: a strap-down inertial navigation system needs initial alignment before underwater work of an underwater vehicle, or a strap-down inertial navigation system needs initial realignment after long-time underwater work, and the position, speed and posture information of a vehicle are transmitted to the strap-down inertial navigation system by using an underwater satellite system under the condition that the vehicle does not emerge from the water, so the precision and speed of the initial alignment are improved, and the reliability and availability of the combined navigation system are improved.

Description

Deep ocean work scale underwater vehicle combined navigation system reaches initial alignment method under water

Technical field

The present invention relates to a kind of deep ocean work scale underwater vehicle combined navigation system and initial alignment method under water, before particularly a kind of suitable ROV work the strap-down inertial navigation system initial alignment or work long hours after under situation about not emerging, carry out initial alignment again.

Background technology

The underwater navigation location is the basic premise of ocean development activity and the development of ocean hi-tech; Ocean development need be obtained on a large scale, accurate marine environment data; Need carry out sea floor exploration, underwater survey and Underwater Engineering etc., modern naval battle also develops into gradually and relates to space, aerial, land, sea, reaches the three-dimensional warfare in multilayer space, seabed under water.All these needs the support of sea and underwater navigation location.

The development of satellite navigation and location system makes most of space outerpace of the whole earth surface and the earth realize all weather navigation location; For space probation and exploitation provide navigation and positioning means easily; Simultaneously, also make traditional surveying and mapping technology that the variation of tremendous matter has taken place.Because radiowave can't through-fall, particularly seawater, therefore, for the demand of underwater navigations such as vast rivers and lakes, ocean location, global position system can't satisfy.Although radiowave can not be propagated in seawater,, sonar signal has good propagation characteristic in seawater.Through sonar the continuity of radio signal in water propagated, can realize submarine navigation device navigator fix and detection.

The city of sonar navigation positioning system measurement under water is with respect to the coordinate of baseline battle array; Belong to independently local relative coordinate system; What global position system adopted is the unified rectangular coordinate system in space in the whole world; If can both be integrated in the system, just can realize stereo navigation location under land, the ocean water.

Usually can adopt the ship's classification basis set of global position system and acoustic positioning system and water acoustic navigation positioning system to become to realize the integrated navigation under water under the global coordinates system that this scheme becomes loose coupling method.Promptly through water surface ship link global position system and underwater sound system; Global position system is measured the global space position of ship; The sound ray positioning system is measured the relative coordinate of submarine target and ship under water, through coordinate transform, finds the solution submarine target volume coordinate in the world.All global position systems and underwateracoustic wire system combined system all belong to loosely coupled system.Correspondingly with it exactly satellite navigation and location system is directly designed as the part of acoustic positioning system, be fully integratible into acoustic positioning system inside.Global position system not only need provide the locus, and other relevant information also need be provided, in case global position system can not be worked, acoustic positioning system can not work alone, and it is integrated that this pattern is called tight coupling.Satellite system and satellite intelligence buoyage all is the tight coupling integrated system under water.

Summary of the invention

The object of the present invention is to provide a kind of realization integrated navigation strap-down inertial navigation system under water, be intended to solve prior art aspect, the location problem that exists initial alignment need emerge and aim under water.

The present invention also aims to provide a kind of method of initial alignment under water of integrated navigation strap-down inertial navigation system under water that realizes, to solve the aforementioned problems in the prior better.

The present invention adopts following technical scheme for realizing above-mentioned purpose:

Deep ocean work scale underwater vehicle combined navigation of the present invention system; Comprise satellite constellation, difference satellite base station, satellite buoyage, underwater navigation transceiver and ship base data control center; Wherein satellite constellation and difference satellite base station radio communication; Difference satellite base station is connected with ship base data control center through the sea Radio Communications Link respectively with the satellite buoyage; The underwater navigation transceiver is connected with the satellite buoyage through the underwater acoustic communication link, and the underwater navigation transceiver is connected through the underwater acoustic communication link bidirectional with ship base data control center.

The initial alignment method may further comprise the steps under the deep ocean work scale underwater vehicle combined navigation system water:

(1) ship base data control center sends the sonar pulse signal of a request location to the underwater navigation transceiver of submarine navigation device;

(2) the underwater navigation transceiver is to satellite buoyage emission hydrolocation signal;

(3) after the satellite buoyage receives the hydrolocation signal; With the hydrolocation signal data and the satellite-signal data that receive are encoded and modulation obtains radio signal, utilize the sea Radio Communications Link that radio signal is sent to ship base data control center;

(4) ship base data control center calculates the radio signal of each satellite buoyage the position of submarine navigation device;

(5) ship base data control center utilizes underwater sound projector that modulation signal is transmitted into the underwater navigation transceiver with the position of the submarine navigation device that calculates with hydrolocation signal x time is encoded and modulation obtains modulation signal; The underwater navigation transceiver calculates navigational parameter and current time according to modulation signal.

Preferably, the described underwater navigation transceiver of step (5) comprises following steps according to the method that modulation signal calculates navigational parameter and current time:

(a) underwater navigation transceiver locator data is gathered: adopt integrated navigation computer with cycle T _GContinuing to read the navigation information that the underwater navigation transceiver receives is modulation signal; And understand; Obtain real-time three-dimensional position, three-dimensional velocity and course angle ψ and the time t of ROV; Wherein, three-dimensional position comprises longitude λ, dimension L and height H, and three-dimensional velocity comprises the east orientation speed V under the local geographic coordinate system _E, north orientation speed V _NWith the sky to speed V _U

(b) satellite navigation locator data buffer memory: remain on three-dimensional position, three-dimensional velocity, course angle and the temporal information of the ROV described in the step (a) in the lump in the memory headroom variable of navigational computer, obtain longitude λ behind the buffer memory _K-1, latitude L _K-1, H _K-1Highly, east orientation speed V _{E, k-1}, north orientation speed V _{N, k-1}With the sky to speed V _{U, k-1}, course angle ψ _K-1, temporal information t _K-1

(c) Inertial Measurement Unit data acquisition: with cycle T _IRead the three dimensional angular speed and the three-dimensional specific force of gyro and accelerometer measures in the Inertial Measurement Unit, the information that the Strapdown Inertial Units measuring unit records is the projection under carrier coordinate system b of moving of ROV religion motion and line, and three dimensional angular speed and three-dimensional specific force are respectively

With

T wherein _GBe T _IIntegral multiple, x, y, z represent three coordinate axis of carrier system;

(d) calculating of ROV acceleration of motion: through at least 2 cycle T _GTime after, understand t constantly accomplishing satellite information _k, longitude λ is arranged in the integrated navigation computer _k, latitude L _k, height H _k, east orientation speed V _{E, k}, north orientation speed V _{N, k}, the sky is to speed V _{U, k}, course angle ψ _k, calculate the east orientation, north orientation of ROV and day to acceleration of motion by following front and back method of difference:

$a_E=\frac{V_{E,k}-V_{E,k-1}}{T_G},$

$a_N=\frac{V_{N,k}-V_{N,k-1}}{T_G},$

$a_U=\frac{V_{U,k}-V_{U,k-1}}{T_G};$

(e) real time position, speed, the acceleration of motion that step (a), step (c) and step (d) are obtained, substitution strapdown inertial navigation system specific force equation calculates the three-dimensional specific force under the navigation system, and its computing method are following:

$\left[\begin{array}{c}{f}_E\\ f_N\\ f_U\end{array}\right]=\begin{array}{}\end{array}\left[\begin{array}{c}{a}_E\\ a_N\\ a_U\end{array}\right]+\left[\begin{array}{ccc}0& -(2{\mathrm{\ω}}_{\mathrm{ieU}}^n+{\mathrm{\ω}}_{\mathrm{enU}}^n)& (2{\mathrm{\ω}}_{\mathrm{ieN}}^n+{\mathrm{\ω}}_{\mathrm{enN}}^n)\\ (2{\mathrm{\ω}}_{\mathrm{ieU}}^n+{\mathrm{\ω}}_{\mathrm{enU}}^n)& 0& -(2{\mathrm{\ω}}_{\mathrm{ieE}}^n+{\mathrm{\ω}}_{\mathrm{enE}}^n)\\ -(2{\mathrm{\ω}}_{\mathrm{ieN}}^n+{\mathrm{\ω}}_{\mathrm{enN}}^n)& (2{\mathrm{\ω}}_{\mathrm{ieE}}^n+{\mathrm{\ω}}_{\mathrm{enE}}^n)& 0\end{array}\right]\left[\begin{array}{c}{V}_{E,k}\\ V_{N,k}\\ V_{U,k}\end{array}\right]-\left[\begin{array}{c}0\\ 0\\ g_0\end{array}\right],$

In the formula, navigation coordinate system rotational-angular velocity of the earth down can be calculated by rotational-angular velocity of the earth and local latitude in the projection of navigation coordinate system:

${\mathrm{\ω}}_{\mathrm{ie}}^N=\left[\begin{array}{c}{\mathrm{\ω}}_{\mathrm{ieE}}^n\\ {\mathrm{\ω}}_{\mathrm{ieN}}^n\\ {\mathrm{\ω}}_{\mathrm{ieU}}^n\end{array}\right]=\left[\begin{array}{c}0\\ {\mathrm{\ω}}_{\mathrm{ie}}\cos L\\ {\mathrm{\ω}}_{\mathrm{ie}}\sin L\end{array}\right],$

Navigation coordinate system can be calculated by headway and local latitude, the earth radius of ROV with respect to earth rotational angular velocity:

${\mathrm{\ω}}_{\mathrm{en}}^n=\left[\begin{array}{c}{\mathrm{\ω}}_{\mathrm{enE}}^n\\ {\mathrm{\ω}}_{\mathrm{enN}}^n\\ {\mathrm{\ω}}_{\mathrm{enU}}^n\end{array}\right]=\left[\begin{array}{c}-\frac{V_{N,k}}{R}\\ \frac{V_{E,k}}{R}\\ \frac{V_{E,k}}{R}\mathrm{tgL}\end{array}\right],$

Three-dimensional specific force [the f that navigation coordinate system calculates down _Ef _Nf _U] ^TAnd the specific force under the carrier coordinate system that obtains of step (c) Between concern just like down conversion:

${\left[\begin{array}{ccc}{f}_x^b& f_y^b& f_z^b\end{array}\right]}^T=C_n^b{\left[\begin{array}{ccc}{f}_E& f_N& f_U\end{array}\right]}^T,$

$C_n^b=\left[\begin{array}{ccc}\cos \mathrm{\γ}\cos \mathrm{\ψ}+\sin \mathrm{\γ}\sin \mathrm{\θ}\sin \mathrm{\ψ}& -\cos \mathrm{\γ}\sin \mathrm{\ψ}+\sin \mathrm{\γ}\sin \mathrm{\θ}\cos \mathrm{\ψ}& -\sin \mathrm{\γ}\cos \mathrm{\θ}\\ \cos \mathrm{\θ}\sin \mathrm{\ψ}& \cos \mathrm{\θ}\cos \mathrm{\ψ}& \sin \mathrm{\θ}\\ \sin \mathrm{\γ}\cos \mathrm{\ψ}-\cos \mathrm{\γ}\sin \mathrm{\θ}\sin \mathrm{\ψ}& -\sin \mathrm{\γ}\sin \mathrm{\ψ}-\cos \mathrm{\γ}\sin \mathrm{\θ}\cos \mathrm{\ψ}& \cos \mathrm{\γ}\cos \mathrm{\θ}\end{array}\right],$

ψ, θ, γ are respectively course angle, pitch angle and roll angle;

(f) with the roll angle and the pitch angle of trying to achieve in the step (e); With acquired longitude, latitude, highly, east orientation speed, north orientation speed, day form original state to speed, course angle; The navigational parameter of initialization strapdown inertial navigation system is realized the moving pedestal initial alignment of the dynamic underway strapdown inertial navigation system of carrier.

The present invention's advantage compared with prior art is:

The present invention is directed to before the work of deep ocean work submarine navigation device after the moving pedestal initial alignment and long working again aligning problem; Advantage in conjunction with satellite navigation system and water acoustic navigation system; Initial alignment is under water improved; Realize utilizing under water the advantage of the resource of satellite navigation system, improved the reliabilty and availability of system.

Description of drawings

Fig. 1 is the overall pie graph of hardware system of the present invention.

Label among the figure: satellite constellation 1, difference satellite base station 2, satellite buoyage 3, underwater navigation transceiver 4, ship base data control center 5, sea Radio Communications Link 6, underwater acoustic communication link 7.

Embodiment

Be elaborated below in conjunction with the technical scheme of accompanying drawing to invention:

As shown in Figure 1, deep ocean work scale underwater vehicle combined navigation system is made up of Navsat constellation, satellite buoyage, underwater navigation R-T unit, control center and strap-down inertial navigation system.

The initial alignment method is following under the deep ocean work scale underwater vehicle combined navigation system water:

(1) need carry out before the submarine navigation device work needing initial alignment again after initial alignment or the work for a long time; Data Control Center sends the sonar pulse signal of a request location to the underwater navigation transceiver of submarine navigation device; After the underwater navigation transceiver receives this pulse, again to satellite buoy generation hydrolocation signal;

(2) the underwater navigation transceiver is to satellite buoy locating hydrophones emission hydrolocation signal;

(3) after the satellite buoyage receives the hydrolocation signal, hydrolocation signal data and satellite-signal data are encoded and modulated, utilize radiotelegraphy to be sent to ship base data control center;

(4) Data Control Center carries out overall treatment with the radio signal of each satellite buoyage, calculates the position of submarine navigation device.

(5) Data Control Center is encoded the submarine navigation device that calculates and underwater sound signal x time and is modulated, and utilizes underwater sound projector that this modulation signal is transmitted into the underwater navigation transceiver; And

The underwater navigation transceiver further calculates navigational parameter and current time after obtaining position and moment data.

Said satellite buoy utilizes the satellite antenna receiving satellite signal; Utilize locating hydrophones to accept the hydrolocation signal; Utilize the DVB clock interface to carry out the Time delay measurement of hydrolocation signal; Set up the time reference of location under water, after with said satellite-signal, nautical receiving set Time delay measurement signal and buoy status data coding, modulation, be emitted to Data Control Center through wireless aerial;

Said underwater navigation transceiver response request hydrolocation signal generates or directly generates the hydrolocation signal through user interface; And just like that through transmitting transducer that this hydrolocation signal is transmitted into said satellite buoy; Receive the positioning result data that pass under the said Data Control Center through the communication transducer, further calculate navigational parameter.

After affiliated Data Control Center receives the radio signal of satellite buoy and difference base station; Utilize the motion state parameters of the satellite-signal data in real time mensuration satellite buoy of each buoy; And reduction constitutes the sea dynamic geodesy benchmark of location under water to the buoy locating hydrophones; According to the time data of nautical receiving set Time delay measurement, employing time or fragrance method of difference are confirmed the three-dimensional position of underwater navigation transceiver and are transmitted into the underwater navigation transceiver;

Described sea Radio Communications Link is carried out the satellite buoy and is transmitted to the signal in real time of the satellite differential signal of Data Control Center to the various signals of the buoy of Data Control Center, differential reference station;

The described link of underwater sound communication is under water carried out the underwater sound data communication between Data Control Center and the underwater navigation transceiver;

System adopts the geodetic surveying coordinate system, and maintenance is consistent with the reference frame of land, spatial information.

After DVB receives signal, carry out initial alignment, it is characterized in that comprising following steps through a series of strap-down inertial navigation system of getting it right of separating:

(a) the satellite navigation receiver locator data is gathered: integrated navigation computer is with cycle T _GContinue to read the navigation information of the specific format of satellite navigation receiver output from the interface that satellite navigation receiver links to each other; And understand; Obtain real-time three-dimensional position, three-dimensional velocity and the course angle of ROV, wherein, three-dimensional position comprises longitude λ; Dimension L and height H, the east orientation speed V under the local geographic coordinate system _E, north orientation speed V _NWith the sky to speed V _U, course angle ψ;

(b) satellite navigation locator data buffer memory: in three-dimensional position, three-dimensional velocity and the position angle of the satellite navigation receiver output of the boat computing machine of the combination of reading in the step (1) and memory headroom variable that temporal information remains on navigational computer in the lump, the variable behind the buffer memory with this with sign of lambda _K-1Expression longitude, L _K-1The expression latitude, H _K-1The expression height, V _{E, k-1}, V _{N, k-1}, V _{U, k-1}Represent east orientation, north orientation and sky respectively to speed, ψ _K-1The expression position angle, t _K-1Express time information;

(c) Inertial Measurement Unit data acquisition: immediately following step (2), through analog to digital conversion or serial port, with cycle T _IRead the three dimensional angular speed and the three-dimensional specific force of gyro and accelerometer measures in the Inertial Measurement Unit, the information that the Strapdown Inertial Units measuring unit records is the projection under carrier coordinate system b of moving of ROV religion motion and line, and three dimensional angular speed and three-dimensional specific force are respectively

With

T wherein _GBe T _IIntegral multiple, x, y, z represent three coordinate axis of carrier system;

(d) calculating of ROV acceleration of motion: obtain satellite navigation data first, and through at least 2 cycle T _GTime after, understand t constantly accomplishing satellite information _k, longitude λ is arranged in the integrated navigation computer _k, latitude L _k, height H _k, east orientation speed V _{E, k}, north orientation speed V _{N, k}, the sky is to speed V _{U, k}, course angle ψ _k, press the acceleration of motion that following front and back method of difference is calculated ROV:

$a_E=\frac{V_{E,k}-V_{E,k-1}}{T_G},$

$a_N=\frac{V_{N,k}-V_{N,k-1}}{T_G},$

$a_U=\frac{V_{U,k}-V_{U,k-1}}{T_G};$

(e) real time position, speed, the acceleration of motion that step (a), step (c) and step (d) are obtained, substitution strapdown inertial navigation system specific force equation calculates the three-dimensional specific force under the navigation system, and its computing method are following:

$\left[\begin{array}{c}{f}_E\\ f_N\\ f_U\end{array}\right]=\begin{array}{}\end{array}\left[\begin{array}{c}{a}_E\\ a_N\\ a_U\end{array}\right]+\left[\begin{array}{ccc}0& -(2{\mathrm{\ω}}_{\mathrm{ieU}}^n+{\mathrm{\ω}}_{\mathrm{enU}}^n)& (2{\mathrm{\ω}}_{\mathrm{ieN}}^n+{\mathrm{\ω}}_{\mathrm{enN}}^n)\\ (2{\mathrm{\ω}}_{\mathrm{ieU}}^n+{\mathrm{\ω}}_{\mathrm{enU}}^n)& 0& -(2{\mathrm{\ω}}_{\mathrm{ieE}}^n+{\mathrm{\ω}}_{\mathrm{enE}}^n)\\ -(2{\mathrm{\ω}}_{\mathrm{ieN}}^n+{\mathrm{\ω}}_{\mathrm{enN}}^n)& (2{\mathrm{\ω}}_{\mathrm{ieE}}^n+{\mathrm{\ω}}_{\mathrm{enE}}^n)& 0\end{array}\right]\left[\begin{array}{c}{V}_{E,k}\\ V_{N,k}\\ V_{U,k}\end{array}\right]-\left[\begin{array}{c}0\\ 0\\ g_0\end{array}\right],$

In the formula, navigation coordinate system rotational-angular velocity of the earth down can be calculated by rotational-angular velocity of the earth and local latitude in the projection of navigation coordinate system:

${\mathrm{\ω}}_{\mathrm{ie}}^N=\left[\begin{array}{c}{\mathrm{\ω}}_{\mathrm{ieE}}^n\\ {\mathrm{\ω}}_{\mathrm{ieN}}^n\\ {\mathrm{\ω}}_{\mathrm{ieU}}^n\end{array}\right]=\left[\begin{array}{c}0\\ {\mathrm{\ω}}_{\mathrm{ie}}\cos L\\ {\mathrm{\ω}}_{\mathrm{ie}}\sin L\end{array}\right],$

Navigation coordinate system can be calculated by headway and local latitude, the earth radius of ROV with respect to earth rotational angular velocity:

${\mathrm{\ω}}_{\mathrm{en}}^n=\left[\begin{array}{c}{\mathrm{\ω}}_{\mathrm{enE}}^n\\ {\mathrm{\ω}}_{\mathrm{enN}}^n\\ {\mathrm{\ω}}_{\mathrm{enU}}^n\end{array}\right]=\left[\begin{array}{c}-\frac{V_{N,k}}{R}\\ \frac{V_{E,k}}{R}\\ \frac{V_{E,k}}{R}\mathrm{tgL}\end{array}\right],$

Three-dimensional specific force [the f that navigation coordinate system calculates down _Ef _Nf _U] ^TAnd the specific force under the carrier coordinate system that obtains of step (c)

Between concern just like down conversion:

${\left[\begin{array}{ccc}{f}_x^b& f_y^b& f_z^b\end{array}\right]}^T=C_n^b{\left[\begin{array}{ccc}{f}_E& f_N& f_U\end{array}\right]}^T,$

$C_n^b=\left[\begin{array}{ccc}\cos \mathrm{\γ}\cos \mathrm{\ψ}+\sin \mathrm{\γ}\sin \mathrm{\θ}\sin \mathrm{\ψ}& -\cos \mathrm{\γ}\sin \mathrm{\ψ}+\sin \mathrm{\γ}\sin \mathrm{\θ}\cos \mathrm{\ψ}& -\sin \mathrm{\γ}\cos \mathrm{\θ}\\ \cos \mathrm{\θ}\sin \mathrm{\ψ}& \cos \mathrm{\θ}\cos \mathrm{\ψ}& \sin \mathrm{\θ}\\ \sin \mathrm{\γ}\cos \mathrm{\ψ}-\cos \mathrm{\γ}\sin \mathrm{\θ}\sin \mathrm{\ψ}& -\sin \mathrm{\γ}\sin \mathrm{\ψ}-\cos \mathrm{\γ}\sin \mathrm{\θ}\cos \mathrm{\ψ}& \cos \mathrm{\γ}\cos \mathrm{\θ}\end{array}\right],$

ψ, θ, γ are respectively course angle, pitch angle and roll angle, can be in the hope of roll angle and pitch angle through equation.

(f) with the roll angle and the pitch angle of trying to achieve in the step (e); With acquired longitude, latitude, highly, east orientation speed, north orientation speed, day form original state to speed, course angle; The navigational parameter of initialization strapdown inertial navigation system is realized the moving pedestal initial alignment of the dynamic underway strapdown inertial navigation system of carrier.

Claims (1)

1. initial alignment method under the deep ocean work scale underwater vehicle combined navigation system water may further comprise the steps:

(1) ship base data control center (5) sends the sonar pulse signal of a request location to the underwater navigation transceiver (4) of submarine navigation device;

(2) underwater navigation transceiver (4) is to satellite buoyage (3) emission hydrolocation signal;

(3) after satellite buoyage (3) receives the hydrolocation signal; With the hydrolocation signal data and the satellite-signal data that receive are encoded and modulation obtains radio signal, utilize sea Radio Communications Link (6) that radio signal is sent to ship base data control center (5);

(4) ship base data control center (5) calculates the radio signal of each satellite buoyage (3) position of submarine navigation device;

(5) ship base data control center (5) utilizes underwater sound projector that modulation signal is transmitted into underwater navigation transceiver (4) with the position of the submarine navigation device that calculates with hydrolocation signal x time is encoded and modulation obtains modulation signal; Underwater navigation transceiver (4) calculates navigational parameter and current time according to modulation signal; It is characterized in that the described underwater navigation transceiver of step (5) (4) comprises following steps according to the method that modulation signal calculates navigational parameter and current time:

(a) underwater navigation transceiver (4) locator data collection: adopt integrated navigation computer with cycle T _GContinuing to read the navigation information that underwater navigation transceiver (4) receives is modulation signal; And understand; Obtain real-time three-dimensional position, three-dimensional velocity and course angle ψ and the time t of ROV; Wherein, three-dimensional position comprises longitude λ, latitude L and height H, and three-dimensional velocity comprises the east orientation speed V under the local geographic coordinate system _E, north orientation speed V _NWith the sky to speed V _U

(b) satellite navigation locator data buffer memory: remain on three-dimensional position, three-dimensional velocity, course angle and the temporal information of the ROV described in the step (a) in the lump in the memory headroom variable of navigational computer, obtain longitude λ behind the buffer memory _K-1, latitude L _K-1, H _K-1Highly, east orientation speed V _{E, k-1}, north orientation speed V _{N, k-1}With the sky to speed V _{U, k-1}, course angle ψ _K-1, temporal information t _K-1

(c) Inertial Measurement Unit data acquisition: with cycle T _IRead the three dimensional angular speed and the three-dimensional specific force of gyro and accelerometer measures in the Inertial Measurement Unit, the information that the Strapdown Inertial Units measuring unit records is ROV angular motion and the projection of line motion under carrier coordinate system b, and three dimensional angular speed and three-dimensional specific force are respectively

With T wherein _GBe T _IIntegral multiple, x, y, z represent three coordinate axis of carrier system;

(d) calculating of ROV acceleration of motion: through at least 2 cycle T _GTime after, understand t constantly accomplishing satellite information _k, longitude λ is arranged in the integrated navigation computer _k, latitude L _k, height H _k, east orientation speed V _{E, k}, north orientation speed V _{N, k}, the sky is to speed V _{U, k}, course angle ψ _k, calculate the east orientation, north orientation of ROV and day to acceleration of motion by following front and back method of difference:

(e) real time position, speed, the acceleration of motion that step (a), step (c) and step (d) are obtained, substitution strapdown inertial navigation system specific force equation calculates the three-dimensional specific force under the navigation system, and its computing method are following:

In the formula, navigation coordinate system rotational-angular velocity of the earth down can be calculated by rotational-angular velocity of the earth and local latitude in the projection of navigation coordinate system:

Navigation coordinate system can be calculated by headway and local latitude, the earth radius of ROV with respect to earth rotational angular velocity:

Three-dimensional specific force [the f that navigation coordinate system calculates down _Ef _Nf _U] ^TAnd the specific force under the carrier coordinate system that obtains of step (c)

Between concern just like down conversion:

ψ, θ, γ are respectively course angle, pitch angle and roll angle;

(f) with the roll angle and the pitch angle of trying to achieve in the step (e); With acquired longitude, latitude, highly, east orientation speed, north orientation speed, day form original state to speed, course angle; The navigational parameter of initialization strapdown inertial navigation system is realized the moving pedestal initial alignment of the dynamic underway strapdown inertial navigation system of carrier.

Images