CN106054135A

CN106054135A - Passive underwater sound positioning method based on moving time window periodically

Info

Publication number: CN106054135A
Application number: CN201610312943.7A
Authority: CN
Inventors: 张涛; 王自强; 朱永云; 胡贺庆; 杨书天
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2016-05-12
Filing date: 2016-05-12
Publication date: 2016-10-26
Anticipated expiration: 2036-05-12
Also published as: CN106054135B

Abstract

The invention discloses a passive underwater acoustic positioning method based on a periodically moving time window, which consists of a strapdown inertial navigation system SINS, a single hydrophone (receiver) at the bottom of an AUV, and a single hydrophone (with a sound source) at the bottom of the sea. Using a time window model based on the period of the ultrasonic waves emitted by the submarine hydrophone, the time delay difference is obtained by performing generalized cross-correlation on the sound source signals received by the AUV at different positions within the time window, and then by calculating the time delay inside the time window The AUV multi-point model obtains the latest position coordinates of the AUV. The present invention calculates through the AUV multi-point model inside the time window, and the AUV navigation distance does not need to be too far, thereby effectively reducing the positioning error caused by the continuous accumulation of the inertial navigation system over time. In the present invention, the AUV does not need to come out of the water to update its position, no data communication is required, and the AUV passively accepts ultrasonic signals, so it is not easy to expose its position, thus improving the concealment and safety of the AUV.

Description

A Passive Underwater Acoustic Positioning Method Based on Periodically Moving Time Window

技术领域technical field

本发明属于捷联惯性导航技术领域，尤其涉及为一种基于周期移动时间窗的被动水声定位方法。The invention belongs to the technical field of strapdown inertial navigation, and in particular relates to a passive underwater acoustic positioning method based on a periodically moving time window.

背景技术Background technique

AUV(Autonomous Underwater Vehicle，自主式水下航行器)现在在执行各种水下任务中发挥着重要的作用，其中包括海洋探测、水下排雷和收集海洋及河流的水深测量数据等。为了保证AUV能够在水下顺利完成任务，并且得到比较精确的水下测量数据，就必须要求其在水下具有长期的自主的高精度定位导航能力，并且具有较高的隐蔽性。AUV (Autonomous Underwater Vehicle, autonomous underwater vehicle) now plays an important role in performing various underwater tasks, including ocean detection, underwater mine clearance, and collecting bathymetric data of oceans and rivers. In order to ensure that AUV can successfully complete its tasks underwater and obtain relatively accurate underwater measurement data, it must have long-term autonomous high-precision positioning and navigation capabilities underwater, and have high concealment.

现在大部分AUV上使用DVL与SINS进行组合导航，并通过舰位推算的方法来估计位置，但这样会引起惯导系统定位误差随着时间不断累积，而不能满足长期的自主的高精度定位要求。AUV在浅海执行任务时采用的“潜航-水面校正-潜航”的导航模式进行定位导航，即当AUV在水下航行时依靠SINS/DVL进行定位导航，当AUV在水下潜行一定时间后为了校正累积误差，AUV必须上浮水面，使用SINS/GPS组合导航系统进行校正。采用这种方案，虽然能达到校正累积误差的目的，但是必须要求AUV不断往返于水下作业地点与水面之间。这样做不仅影响工作效率，而且更容易暴露AUV的位置。特别是当AUV在深海或者冰下作业时，这种方案更加不切实际。因此，研究一种在水下长期的自主的进行可靠辅助定位的方法十分重要。Now most AUVs use DVL and SINS for integrated navigation, and estimate the position through ship position reckoning, but this will cause the positioning error of the inertial navigation system to accumulate over time, and cannot meet the long-term autonomous high-precision positioning requirements . When the AUV performs tasks in shallow seas, it uses the "submerged-surface correction-submarine" navigation mode for positioning and navigation, that is, when the AUV is navigating underwater, it relies on SINS/DVL for positioning and navigation. To accumulate errors, the AUV must float to the surface and use the SINS/GPS integrated navigation system for correction. Using this scheme, although the purpose of correcting the accumulated errors can be achieved, the AUV must be required to continuously travel between the underwater operation site and the water surface. Doing so not only affects work efficiency, but also makes it easier to expose the position of the AUV. Especially when AUVs operate in deep sea or under ice, this solution is even more impractical. Therefore, it is very important to study a method for long-term autonomous and reliable assisted positioning underwater.

发明内容Contents of the invention

发明目的：本发明针对以往的DVL与SINS进行组合导航方法存在的定位误差会随着时间不断累积、“潜航-水面校正-潜航”的导航模式容易暴露AUV的位置等在AUV水下自主式导航方面存在的问题，提供一种基于周期移动时间窗的被动水声定位方法，利用海底水听器来确定载体的位置，计算出的位置坐标。特别适用于长期的自主的水下高精度定位导航，并且具有较高的隐蔽性。Purpose of the invention: The present invention aims at the positioning errors existing in the combined navigation method of DVL and SINS in the past will accumulate over time, and the navigation mode of "submarine-surface correction-submarine" easily exposes the position of the AUV, etc. in the autonomous navigation of the AUV underwater In order to solve the existing problems, a passive underwater acoustic positioning method based on a periodical moving time window is provided, and the submarine hydrophone is used to determine the position of the carrier and the calculated position coordinates. It is especially suitable for long-term autonomous underwater high-precision positioning and navigation, and has high concealment.

技术方案：一种基于周期移动时间窗的被动水声定位方法，包括以下步骤：Technical solution: a passive underwater acoustic positioning method based on periodic moving time windows, comprising the following steps:

(1)对固定在海底的单个水听器作为声源进行定位，计算其惯性坐标系下的位置坐标P(x,y,z)；(1) Locate a single hydrophone fixed on the seabed as a sound source, and calculate its position coordinates P(x, y, z) in the inertial coordinate system;

(2)海底的水听器时刻保持工作状态，且不断发出周期为t的超声波脉冲信号，当AUV底部固定的水听器作为接收器接收到10个周期的脉冲信号后，即经过时间10t，AUV已经向前行进了一段距离，当AUV底部固定的水听器接收到第11个脉冲信号时，确定并记录AUV当前位置P_i(i＝0,1,2,3…)，此时以脉冲信号的出现作为周期信号的起始位置，接收器接收海底水听器发出的一个周期的声信号x_i(i＝0,1,2,3…)；(2) The hydrophone on the bottom of the sea keeps working at all times, and continuously sends out ultrasonic pulse signals with a period of t. When the hydrophone fixed at the bottom of the AUV serves as a receiver and receives 10 periods of pulse signals, the elapsed time is 10t. The AUV has moved forward for a certain distance. When the hydrophone fixed at the bottom of the AUV receives the 11th pulse signal, determine and record the current position P _i (i=0,1,2,3...) of the AUV. At this time, the The appearance of the pulse signal is used as the initial position of the periodic signal, and the receiver receives a periodic acoustic signal x _i (i=0,1,2,3...) sent by the submarine hydrophone;

(3)AUV在水听器所在附近水域航行时，选取记录下来的4个AUV的连续位置形成时间窗，表示出4个位置P_i(i＝0,1,2,3)绝对地理坐标系下的坐标为：(3) When the AUV is navigating in the waters near the hydrophone, select the recorded continuous positions of the 4 AUVs to form a time window, indicating the absolute geographic coordinate system of the 4 positions P _i (i=0,1,2,3) The coordinates below are:

$\begin{matrix} (({x x}_{00},, {y the y}_{00},, {z z}_{00})) = = (((({x x}_{33} - - {Δx Δx}_{11})),, (({y the y}_{33} - - {Δy Δy}_{11})),, (({z z}_{33} - - {Δz Δz}_{11})))) \\ (({x x}_{11},, {y the y}_{11},, {z z}_{11})) = = (((({x x}_{33} - - {Δx Δx}_{22})),, (({y the y}_{33} - - {Δy Δy}_{22})),, (({z z}_{33} - - {Δz Δz}_{22})))) \\ (({x x}_{22},, {y the y}_{22},, {z z}_{22})) = = (((({x x}_{33} - - {Δx Δx}_{33})),, (({y the y}_{33} - - {Δy Δy}_{33})),, (({z z}_{33} - - {Δz Δz}_{33})))) \\ (({x x}_{33},, {y the y}_{33},, {z z}_{33})) = = (({x x}_{33},, {y the y}_{33},, {z z}_{33})) \end{matrix};;$

(4)由P₃处接收到的声信号分别与P₂、P₁、P₀处接收到的声信号做互相关得到时延差τ₃₂、τ₃₁、τ₃₀：(4) The acoustic signals received at P ₃ are cross-correlated with the acoustic signals received at P ₂ , P ₁ , and P ₀ to obtain delay differences τ ₃₂ , τ ₃₁ , and τ ₃₀ :

Δt_3i＝τ_3i-(30-10i)t，(i＝0,1,2)；Δt _3i =τ _3i -(30-10i)t, (i=0,1,2);

而AUV在P_i(i＝0,1,2,3)处时与海底水听器P(x,y,z)的距离为：When the AUV is at P _i (i=0,1,2,3), the distance from the submarine hydrophone P(x,y,z) is:

${L L}_{i i} = = \sqrt{{(({x x}_{i i} - - x x))}^{22} + + {(({y the y}_{i i} - - y the y))}^{22} + + {(({z z}_{i i} - - z z))}^{22}};;$

所以根据所估计的时延差，水下声速设为恒定值，记为c，得到以下的方程组：Therefore, according to the estimated delay difference, the underwater sound velocity is set to a constant value, denoted as c, and the following equations are obtained:

L₃-L₀＝Δt₃₀cL ₃ −L ₀ =Δt ₃₀ c

L₃-L₁＝Δt₃₁c；L ₃ −L ₁ =Δt ₃₁ c;

L₃-L₂＝Δt₃₂cL ₃ −L ₂ =Δt ₃₂ c

(5)由步骤(3)中的坐标代入的距离公式后再代入方程组后，由方程组中的3个方程得到所需的P₃的坐标(x₃,y₃,z₃)，即AUV此时最新的坐标位置。(5) After the distance formula substituted by the coordinates in step (3) is substituted into the equation group, the required coordinates (x ₃ , y ₃ , z ₃ ) of P3 are obtained from the _three equations in the equation group, namely The latest coordinate position of AUV at this time.

由于随海底水听器发出的脉冲信号周期的移动，以AUV的四个连续位置、形成多个时间窗，对之后的时间窗进行相同计算，可对AUV的位置进行实时跟踪并定位，使用该方法后可以得到更精确的当前位置坐标。Due to the movement of the pulse signal period sent by the submarine hydrophone, multiple time windows are formed with four consecutive positions of the AUV, and the same calculation is performed on the subsequent time windows, so that the position of the AUV can be tracked and positioned in real time. Using this After the method, you can get more accurate current position coordinates.

所述步骤(3)时间窗的表示方法为：The expression method of described step (3) time window is:

1)设定原始AUV的惯性坐标系下的位置坐标为P₀(x₀,y₀,z₀)，在经过时间10t之后，得到当前的位置坐标P₁(x₁,y₁,z₁)，在经过时间20t之后，得到当前的位置坐标P₂(x₂,y₂,z₂)，在经过时间30t之后，得到最新的位置坐标P₃(x₃,y₃,z₃)，此时的四个点形成一个时间窗；1) Set the position coordinates in the inertial coordinate system of the original AUV as P ₀ (x ₀ , y ₀ , z ₀ ), and after 10t, get the current position coordinates P ₁ (x ₁ , y ₁ , z ₁ ), after the elapsed time 20t, get the current position coordinates P ₂ (x ₂ , y ₂ , z ₂ ), after the elapsed time 30t, get the latest position coordinates P ₃ (x ₃ , y ₃ , z ₃ ), The four points at this time form a time window;

2)当海底水听器发出的脉冲信号经过10个周期即10t时，AUV得到当前的惯性坐标系下的位置坐标为P₄(x₄,y₄,z₄)，此时将P₀(x₀,y₀,z₀)从时间窗中删除，并将当前的P₄与P₁、P₂、P₃组成新的时间窗。以此类推，在AUV航行的过程中，时间窗保持10t的周期向后移动；2) When the pulse signal sent by the submarine hydrophone passes through 10 cycles, that is, 10t, the AUV obtains the position coordinates in the current inertial coordinate system as P ₄ (x ₄ , y ₄ , z ₄ ), at this time, P ₀ ( x ₀ , y ₀ , z ₀ ) are deleted from the time window, and the current P ₄ and P ₁ , P ₂ , P ₃ form a new time window. By analogy, in the process of AUV navigation, the time window keeps moving backward at a period of 10t;

3)其中第一个时间窗中，通过母船上的IMU和罗经传感器对AUV当前的航向、速度等信息进行测量并积分运算后得到的10t、20t、30t时间内AUV在绝对地理坐标系中x、y、z轴向的航行距离分别为Δx₁、Δx₂、Δx₃、Δy₁、Δy₂、Δy₃、Δz₁、Δz₂、Δz₃，从而用最新位置P₃(x₃,y₃,z₃)为未知参数，将P_i(i＝0,1,2)表示为：3) In the first time window, the IMU and compass sensor on the mother ship measure the current course, speed and other information of the AUV and integrate and calculate the AUV in the absolute geographic coordinate system within 10t, 20t, and 30t time x , y, and z axes are respectively Δx ₁ , Δx ₂ , Δx ₃ , Δy ₁ , Δy ₂ , Δy ₃ , Δz ₁ , Δz ₂ , Δz ₃ , so the latest position P ₃ (x ₃ ,y ₃ ,z ₃ ) is an unknown parameter, and P _i (i=0,1,2) is expressed as:

(x₀,y₀,z₀)＝((x₃-Δx₁),(y₃-Δy₁),(z₃-Δz₁))(x ₀ ,y ₀ ,z ₀ )=((x ₃ -Δx ₁ ),(y ₃ -Δy ₁ ),(z ₃ -Δz ₁ ))

(x₁,y₁,z₁)＝((x₃-Δx₂),(y₃-Δy₂),(z₃-Δz₂))；(x ₁ ,y ₁ ,z ₁ )=((x ₃ -Δx ₂ ),(y ₃ -Δy ₂ ),(z ₃ -Δz ₂ ));

(x₂,y₂,z₂)＝((x₃-Δx₃),(y₃-Δy₃),(z₃-Δz₃))(x ₂ ,y ₂ ,z ₂ )=((x ₃ -Δx ₃ ),(y ₃ -Δy ₃ ),(z ₃ -Δz ₃ ))

4)后续的时间窗同第一个时间窗的处理方法相同，用最新位置的坐标作为未知参数表示出前三个记录的位置的坐标。4) Subsequent time windows are processed in the same way as the first time window, using the coordinates of the latest position as unknown parameters to represent the coordinates of the first three recorded positions.

所述步骤(4)中互相关得到时延差的方法为：The method that cross-correlation obtains delay difference in described step (4) is:

5)假设水听器在P_i接收到的信号为：5) Suppose the signal received by the hydrophone at P _i is:

x_i(t)＝α_ix(t-τ_i)+n_i(t)；x _i (t)=α _i x(t-τ _i )+n _i (t);

6)水听器在P_j接收到的信号为：6) The signal received by the hydrophone at P _j is:

x_j(t)＝α_jx(t-τ_j)+n_j(t)；x _j (t)=α _j x(t-τ _j )+n _j (t);

其中α_i、α_j为声信号在水中传播的衰减系数，n_i(t)、n_j(t)为互不相关的噪声信号，τ_i、τ_j为传播时间；Among them, α _i and α _j are the attenuation coefficients of acoustic signals propagating in water, n _i (t) and n _j (t) are noise signals that are not correlated with each other, and τ _i and τ _j are propagation times;

7)由步骤(5)的公式对AUV底部的水听器在不同位置接收到的声源信号做广义互相关计算，x_i(t)与x_j(t)的互相关函数为：7) By the formula of step (5), the generalized cross-correlation calculation is performed on the sound source signals received by the hydrophone at the bottom of the AUV at different positions, and the cross-correlation function of x _i (t) and x _j (t) is:

${R R}_{{x x}_{i i} {x x}_{j j}} ((τ τ)) = = E E. [[{x x}_{i i} ((t t)) {x x}^{* *}_{j j} ((t t - - τ τ))]] = = \frac{11}{T T - - τ τ} {&Integral; &Integral;}_{τ τ}^{T T} {x x}_{i i} ((t t)) {x x}_{j j} ((t t - - τ τ)) d d t t;;$

8)其中τ＝τ_j-τ_i，表示到达时间差，_T表示观测时间。根据相关函数的性质，只要找出的峰值，其对应的τ_ij由两部分组成，一是AUV底部固定的水听器在P_i处与P_j处由于与海底水听器距离不同导致声信号传播时间不同而造成的时间差Δt_ij，二是AUV从P_j到P_i位置所经时间kt(k为经过的周期数)。8) where τ=τ _j -τ _i represents the arrival time difference, and _T represents the observation time. According to the properties of the relevant function, it is only necessary to find The peak value of τ _ij is composed of two parts, one is the time difference Δt _ij caused by the difference in the propagation time of the acoustic signal due to the different distance between the hydrophone at the bottom of the AUV at P _i and P _j , and the second is the elapsed time kt (k is the number of cycles passed) for the AUV from P _j to P _i .

有益效果：本发明通过在水底设置单个水听器(带声源)，以及在AUV底部设置单个水听器(接收器)，利用海底水听器持续发送声信号来对载体的位置进行实时更新，计算出的位置坐标是相对于地球坐标系下的坐标，再通过坐标转换，转换成大地坐标系下的经纬度数据。本发明与现有技术相比的优点在于：Beneficial effects: the present invention arranges a single hydrophone (with sound source) at the bottom of the water and a single hydrophone (receiver) at the bottom of the AUV, and uses the submarine hydrophone to continuously send acoustic signals to update the position of the carrier in real time , the calculated position coordinates are relative to the coordinates in the earth coordinate system, and then converted into latitude and longitude data in the earth coordinate system through coordinate conversion. The advantage of the present invention compared with prior art is:

(1)本发明利用海底水听器持续发送声信号来对AUV的位置进行确定，AUV被动接收声信号，具有了较高的隐蔽性，不容易暴露AUV的位置。(1) The present invention uses the submarine hydrophone to continuously send acoustic signals to determine the position of the AUV. The AUV passively receives the acoustic signals, which has high concealment and is not easy to expose the position of the AUV.

(2)本发明采用基于周期移动的时间窗定位方法，以AUV的四个连续位置形成时间窗，并且时间窗根据海底水听器发出的脉冲信号的周期而移动，可对AUV的位置进行实时跟踪并定位，使用该方法后可以有效减少惯导系统随着时间不断累积的定位误差，可以得到更精确的当前位置坐标。(2) The present invention adopts the time window positioning method based on periodical movement, forms the time window with four continuous positions of the AUV, and the time window moves according to the period of the pulse signal sent by the seabed hydrophone, and the position of the AUV can be real-time Tracking and positioning. After using this method, the positioning error accumulated by the inertial navigation system over time can be effectively reduced, and more accurate current position coordinates can be obtained.

附图说明Description of drawings

图1为本发明的流程图；Fig. 1 is a flowchart of the present invention;

图2为本发明的时间窗模型示意框图；Fig. 2 is a schematic block diagram of the time window model of the present invention;

图3为本发明声源信号做广义互相关得到时延差流程图。Fig. 3 is a flow chart of obtaining time delay difference by generalized cross-correlation of sound source signals according to the present invention.

具体实施方式detailed description

下面将结合附图，对本发明的实施案例进行详细的描述；Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings;

如图1，本发明的具体实施步骤如下：As shown in Figure 1, the specific implementation steps of the present invention are as follows:

1)首先AUV通过计算机获取到水下水听器作为带声源在惯性坐标系下的位置坐标P(x,y,z)；1) First, the AUV obtains the position coordinates P(x,y,z) of the underwater hydrophone as a sound source in the inertial coordinate system through the computer;

2)然后设定当前AUV的惯性坐标系下的位置坐标为P₀(x₀,y₀,z₀)，此后AUV向前，并时刻保持接收水听器发出的超声波，在接收到10个周期的超声波后，(即航行经过时间10t)，AUV到达位置P₁，AUV通过母船上的IMU(Inertial measurement unit)和罗经等传感器对AUV当前的航向、速度等信息进行测量并积分运算后，记录当前在惯性坐标系中x、y、z轴向的航行距离分别为Δx₁、Δy₁、Δz₁，并记录下一个周期的超声波信号，记录结束后，AUV继续向前航行，在经过时间20t之后，AUV到达位置P₂，记录当前在惯性坐标系中x、y、z轴向的航行距离分别为Δx₂、Δy₂、Δz₂，并记录下一个周期的超声波信号，在经过时间30t之后，AUV到达位置P₃，记录当前在惯性坐标系中x、y、z轴向的航行距离分别为Δx₃、Δy₃、Δz₃，并记录下一个周期的超声波信号；2) Then set the position coordinates of the current AUV in the inertial coordinate system as P ₀ (x ₀ , y ₀ , z ₀ ), and then the AUV moves forward and keeps receiving the ultrasonic waves from the hydrophone at all times. After receiving 10 After the period of ultrasonic waves, (that is, the voyage elapsed time 10t), the AUV reaches the position P ₁ , and the AUV measures the current heading, speed and other information of the AUV through the IMU (Inertial measurement unit) and compass on the mother ship and performs integral calculations. Record the current voyage distances in the x, y, and z axes of the inertial coordinate system as Δx ₁ , Δy ₁ , and Δz ₁ , and record the ultrasonic signal of the next cycle. After the recording is over, the AUV continues to sail forward. After the elapsed time After 20t, the AUV reaches the position P ₂ , records the current voyage distances in the x, y, and z axes of the inertial coordinate system as Δx ₂ , Δy ₂ , and Δz ₂ , and records the ultrasonic signal of the next cycle. After the elapsed time of 30t Afterwards, the AUV reaches the position P ₃ , records the current voyage distances in the x, y, and z axes of the inertial coordinate system as Δx ₃ , Δy ₃ , and Δz ₃ , and records the ultrasonic signal of the next cycle;

3)当计算机记录了四个位置之后，计算机通过记录的信息，用最新位置P₃的惯性坐标系下的坐标(x₃,y₃,z₃)为未知参数，可将P_i(i＝0,1,2)的坐标表示为：3) After the computer records the four positions, the computer uses the recorded information to use the coordinates (x ₃ , y ₃ , z ₃ ) in the inertial coordinate system of the latest position P ₃ as unknown parameters, and P _i (i= 0,1,2) coordinates are expressed as:

(x₁,y₁,z₁)＝((x₃-Δx₂),(y₃-Δy₂),(z₃-Δz₂))(x ₁ ,y ₁ ,z ₁ )=((x ₃ -Δx ₂ ),(y ₃ -Δy ₂ ),(z ₃ -Δz ₂ ))

1)计算机对P₃处接收到的声信号分别与P₂、P₁、P₀处接收到的声信号做互相关，1) The computer cross-correlates the acoustic signal received at P ₃ with the acoustic signals received at P ₂ , P ₁ , and P ₀ respectively,

如图3，过程如下：As shown in Figure 3, the process is as follows:

假设水听器在P_i接收到的信号为(i＝0,1,2,3)：Suppose the signal received by the hydrophone at P _i is (i=0,1,2,3):

x_i(t)＝α_ix(t-τ_i)+n_i(t)；x _i (t)=α _i x(t-τ _i )+n _i (t);

其中α_i为声信号在水中传播的衰减系数，n_i(t)为互不相关的噪声信号，τ_i为where α _i is the attenuation coefficient of the acoustic signal propagating in water, n _i (t) is the noise signal which is not correlated with each other, τ _i is

传播时间；propagation time;

由步骤(2)中AUV底部的水听器在不同位置接收到的声源信号做广义互相In step (2), the sound source signals received by the hydrophones at the bottom of the AUV at different positions are used for generalized mutual

关计算，x_i(t)(i＝0,1,2)与的x₃(t)互相关函数为：In terms of calculation, the cross-correlation function between x _i (t) (i=0,1,2) and x ₃ (t) is:

${R R}_{{x x}_{i i} {x x}_{33}} ((τ τ)) = = E E. [[{x x}_{i i} ((t t)) {x x}^{* *}_{33} ((t t - - τ τ))]] = = \frac{11}{T T - - τ τ} {&Integral; &Integral;}_{τ τ}^{T T} {x x}_{i i} ((t t)) {x x}_{33} ((t t - - τ τ)) d d t t;;$

其中τ＝τ₃-τ_i，表示到达时间差，T表示观测时间。计算机通过一定的算法找出的峰值，其对应的τ_i3由两部分组成，一是AUV底部固定的水听器作为接收器在P_i处与P₃处由于与海底水听器距离不同导致声信号传播时间不同而造成的时间差Δt_i3，二是AUV从P_i到P₃位置所经时间kt(k为经过的周期数)；Among them, τ=τ ₃ -τ _i represents the arrival time difference, and T represents the observation time. The computer finds out through a certain algorithm , and its corresponding τ _i3 is composed of two parts, one is that the fixed hydrophone at the bottom of the AUV acts as a receiver at P _i and P ₃ due to the difference in the propagation time of the acoustic signal due to the different distance from the submarine hydrophone Time difference Δt _i3 , the second is the time kt elapsed by the AUV from P _i to P ₃ position (k is the number of cycles passed);

所以由P₃处接收到声信号的所需时间与P₂、P₁、P₀处接收到声信号的所需时间的时间差为：Therefore, the time difference between the time required for receiving the acoustic signal at P ₃ and the time required for receiving the acoustic signal at P ₂ , P ₁ , and P ₀ is:

Δt_3i＝τ_3i-(30-10i)t，(i＝0,1,2)；Δt _3i =τ _3i -(30-10i)t, (i=0,1,2);

2)由AUV在P_i(i＝0,1,2,3)处时与海底水听器P(x,y,z)的距离为：2) When the AUV is at P _i (i=0,1,2,3), the distance from the submarine hydrophone P(x,y,z) is:

所以根据计算机得到的时间差，水下声速设为恒定值，记为c，可以得到以下的方程组：Therefore, according to the time difference obtained by the computer, the underwater sound velocity is set to a constant value, denoted as c, and the following equations can be obtained:

L₃-L₀＝Δt₃₀cL ₃ −L ₀ =Δt ₃₀ c

L₃-L₁＝Δt₃₁c；L ₃ −L ₁ =Δt ₃₁ c;

L₃-L₂＝Δt₃₂cL ₃ −L ₂ =Δt ₃₂ c

3)计算机将步骤(3)中的坐标代入的距离公式后再代入方程组后，由方程组中的3个方程可以得到所需的P₃的坐标(x₃,y₃,z₃)，即AUV此时最新的坐标位置，再通过坐标转换成大地坐标系下的经纬度数据，此时第一个时间窗计算完成；3) After the computer substitutes the coordinates in step (3) into the distance formula and then into the equation group, the required coordinates of P3 (x ₃ , y ₃ , z ₃ ) can be obtained from the _three equations in the equation group, That is, the latest coordinate position of the AUV at this time, and then convert the coordinates into the latitude and longitude data in the geodetic coordinate system. At this time, the calculation of the first time window is completed;

4)AUV继续向前航行，海底水听器发出的脉冲信号又经过10个周期即10t时，AUV到达位置P₄，记录当前在惯性坐标系中x、y、z轴向的航行距离分别为Δx₂、Δy₂、Δz₂，并记录下一个周期的超声波信号，此时将P₀(x₀,y₀,z₀)从时间窗中删除，并将当前的P₄与P₁、P₂、P₃组成新的时间窗。以此类推，在AUV航行的过程中，时间窗一直保持10t的周期向后移动；4) The AUV continues to sail forward, and when the pulse signal sent by the submarine hydrophone passes through another 10 cycles, that is, 10t, the AUV reaches the position P ₄ , and records the current sailing distances in the x, y, and z axes of the inertial coordinate system as Δx ₂ , Δy ₂ , Δz ₂ , and record the ultrasonic signal of the next cycle. At this time, delete P ₀ (x ₀ , y ₀ , z ₀ ) from the time window, and compare the current P ₄ with P ₁ , P _2. P ₃ forms a new time window. By analogy, in the process of AUV navigation, the time window has been moving backward at a period of 10t;

5)此后的时间窗同第一个时间窗的处理方法相同，可用最新位置的坐标作为未知参数表示出前三个记录的位置的坐标，从而得到最新位置的坐标的准确值；5) The subsequent time window is treated the same as the first time window, and the coordinates of the latest position can be used as unknown parameters to represent the coordinates of the first three recorded positions, thereby obtaining the exact value of the coordinates of the latest position;

本发明针对现有技术中的两种情况提出了有效的解决方式：由捷联惯性导航系统SINS、AUV底部的单水听器(接收器)以及海底单水听器(带声源)组成。采用基于海底水听器发出的超声波的周期而移动的时间窗模型，在时间窗内部通过对AUV处于不同位置时接收到的声源信号做广义互相关得到时延差，再通过计算时间窗内部AUV多点模型得到AUV最新位置坐标。由于时间窗基于超声波周期不断向前移动，能够达到较好的定位精度并且增加系统的冗余性。本发明通过时间窗内部AUV多点模型计算，AUV航行距离无需过远，从而有效减小了惯导系统随着时间不断累积而造成的定位误差。本发明中AUV无需上浮出水面进行位置更新，无需数据通信且AUV被动接受超声波信号，不易暴露位置，提高了AUV的隐蔽性和安全性。The present invention proposes an effective solution to two situations in the prior art: it consists of a strapdown inertial navigation system SINS, a single hydrophone (receiver) at the bottom of the AUV, and a single hydrophone (with sound source) at the bottom of the sea. Using a time window model based on the period of the ultrasonic waves emitted by the submarine hydrophone, the time delay difference is obtained by performing generalized cross-correlation on the sound source signals received by the AUV at different positions within the time window, and then calculating the time delay difference inside the time window The AUV multi-point model obtains the latest position coordinates of the AUV. Since the time window is continuously moved forward based on the ultrasonic cycle, better positioning accuracy can be achieved and the redundancy of the system can be increased. The present invention calculates through the AUV multi-point model inside the time window, and the AUV navigation distance does not need to be too far, thereby effectively reducing the positioning error caused by the continuous accumulation of the inertial navigation system over time. In the present invention, the AUV does not need to come out of the water to update its position, no data communication is required, and the AUV passively accepts ultrasonic signals, so it is not easy to expose the position, and the concealment and safety of the AUV are improved.

Claims

1. a passive underwater acoustic localization method based on cycle traveling time window, it is characterised in that comprise the following steps:

(1) the single hydrophone being fixed on seabed is positioned as sound source, calculate the position coordinates P under its inertial coodinate system (x,y,z)；

(2) the hydrophone moment in seabed keeps duty, and constantly sends the ultrasonic pulse signal that the cycle is t, when at the bottom of AUV After the hydrophone that portion is fixed receives the pulse signal in 10 cycles as receptor, i.e. elapsed time 10t, AUV are the most forward Travel a segment distance, when hydrophone fixing bottom AUV receives the 11st pulse signal, determine and record that AUV is current Position P_i(i=0,1,2,3 ...), now using the original position as periodic signal that occurs of pulse signal, receptor reception sea Acoustical signal x in the cycle that end hydrophone sends_i(i=0,1,2,3 ...)；

(3) AUV is when hydrophone place Its Adjacent Waters navigates by water, and the continuous position choosing 4 AUV recorded forms the time Window, there is shown 4 position P_i(i=0,1,2,3) coordinate under absolute geographic coordinate system is:

\begin{matrix} (x_{0}, y_{0}, z_{0}) = ((x_{3} - {Δx}_{1}), (y_{3} - {Δy}_{1}), (z_{3} - {Δz}_{1})) \\ (x_{1}, y_{1}, z_{1}) = ((x_{3} - {Δx}_{2}), (y_{3} - {Δy}_{2}), (z_{3} - {Δz}_{2})) \\ (x_{2}, y_{2}, z_{2}) = ((x_{3} - {Δx}_{3}), (y_{3} - {Δy}_{3}), (z_{3} - {Δz}_{3})) \\ (x_{3}, y_{3}, z_{3}) = (x_{3}, y_{3}, z_{3}) \end{matrix};

(4) by P₃The acoustical signal that place receives respectively with P₂、P₁、P₀The acoustical signal that place receives is done cross-correlation and is obtained delay inequality τ₃₂、 τ₃₁、τ₃₀:

Δt_3i=τ_3i-(30-10i) t, (i=0,1,2)；

And AUV is at P_i(i=0,1,2,3) during place with seabed hydrophone P (x, y, distance z) is:

L_{i} = \sqrt{{(x_{i} - x)}^{2} + {(y_{i} - y)}^{2} + {(z_{i} - z)}^{2}};

So according to estimated delay inequality, the velocity of sound is set to steady state value under water, it is designated as c, obtains below equation group:

\begin{matrix} L_{3} - L_{0} = {Δt}_{30} c \\ L_{3} - L_{1} = {Δt}_{31} c \\ L_{3} - L_{2} = {Δt}_{32} c \end{matrix};

(5) after substituting into equation group again after the range formula substituted into by the coordinate in step (3), 3 equations in equation group obtain To required P₃Coordinate (x₃,y₃,z₃), i.e. the coordinate position that AUV is the most up-to-date.

A kind of passive underwater acoustic localization method based on cycle traveling time window the most according to claim 1, it is characterised in that The method for expressing of described step (3) time window is:

1) position coordinates under the inertial coodinate system of original AUV is set as P₀(x₀,y₀,z₀), after elapsed time 10t, obtain Current position coordinates P₁(x₁,y₁,z₁), after elapsed time 20t, obtain current position coordinates P₂(x₂,y₂,z₂), at warp After crossing time 30t, obtain up-to-date position coordinates P₃(x₃,y₃,z₃), four points now form a time window；

2) pulse signal sent when seabed hydrophone is through 10 cycle i.e. 10t, and AUV obtains under current inertial coodinate system Position coordinates be P₄(x₄,y₄,z₄), now by P₀(x₀,y₀,z₀) delete from time window, and by current P₄With P₁、P₂、P₃ Form new time window.By that analogy, during AUV navigates by water, time window keeps the cycle of 10t to be moved rearwards by；

3), wherein in first time window, by the IMU on lash ship and compass sensor, course current for AUV, speed etc. are believed In ceasing 10t, 20t, 30t time measuring and obtaining after integral operation, AUV x, y, z in absolute geographic coordinate system is axial Distance to go is respectively Δ x₁、Δx₂、Δx₃、Δy₁、Δy₂、Δy₃、Δz₁、Δz₂、Δz₃, thus use latest position P₃(x₃, y₃,z₃) it is unknown parameter, by P_i(i=0,1,2) it is expressed as:

\begin{matrix} (x_{0}, y_{0}, z_{0}) = ((x_{3} - {Δx}_{1}), (y_{3} - {Δy}_{1}), (z_{3} - {Δz}_{1})) \\ (x_{1}, y_{1}, z_{1}) = ((x_{3} - {Δx}_{2}), (y_{3} - {Δy}_{2}), (z_{3} - {Δz}_{2})) \\ (x_{2}, y_{2}, z_{2}) = ((x_{3} - {Δx}_{3}), (y_{3} - {Δy}_{3}), (z_{3} - {Δz}_{3})) \end{matrix};

4) follow-up time window is identical with the processing method of first time window, with the coordinate of latest position as unknown parameter table The coordinate of first three position recorded is shown.

A kind of passive underwater acoustic localization method based on cycle traveling time window the most according to claim 1, it is characterised in that In described step (4), cross-correlation obtains the method for delay inequality and is:

5) assume that hydrophone is at P_iThe signal received is:

x_i(t)=α_ix(t-τ_i)+n_i(t)；6) hydrophone is at P_jThe signal received is:

x_j(t)=α_jx(t-τ_j)+n_j(t)；

Wherein α_i、α_jFor acoustical signal at the attenuation quotient of water transmission, n_i(t)、n_jT () is orthogonal noise signal, τ_i、τ_j For the propagation time；

7) by the formula of step (5), the hydrophone bottom AUV is done broad sense cross-correlation at the sound-source signal that diverse location receives Calculate, x_i(t) and x_jT the cross-correlation function of () is:

R_{x_{i} x_{j}} (τ) = E [x_{i} (t) {x^{*}}_{j} (t - τ)] = \frac{1}{T - τ} {&Integral;}_{τ}^{T} x_{i} (t) x_{j} (t - τ) d t;

8) wherein τ=τ_j-τ_i, representing that the time of advent is poor, T represents observation time.According to the character of correlation function, as long as finding outPeak value, the τ of its correspondence_ijBeing made up of two parts, one is that hydrophone fixing bottom AUV is at P_iPlace and P_jPlace due to The different time difference Δ t causing acoustic signal propagation time different and to cause of seabed hydrophone distance_ij, two is that AUV is from P_jTo P_iPosition Put through time kt (k be through periodicity).