WO2021061078A1

WO2021061078A1 - A laser-based underwater location detection assembly and method

Info

Publication number: WO2021061078A1
Application number: PCT/TR2020/050877
Authority: WO
Inventors: Mehmet Cahit ÖZDEMİR; Gökhan BARIŞ; Erten ERÖZDEN
Original assignee: Roketsan Roket Sanayi̇i̇ Ti̇caret A.Ş.
Priority date: 2019-09-27
Filing date: 2020-09-23
Publication date: 2021-04-01
Also published as: TR201914765A2

Abstract

The invention is an underwater location detection assembly for an underwater system which is provided on an underwater body (10) and comprises a casing (12) having a laser transmissive section (14), characterized in that, it comprises a laser source (16) which is adjusted to a predetermined power output value (P) forming an indicator (45) with the refraction of a laser beam (40) that travels underwater (20) on the surface (22) of the water body (24) in which the underwater body (10) is submerged and is positioned in a casing (12) by being aligned to the laser transmissive section (14) and a controller (11) which activates the laser source (16) in a location detection mode.

Description

A LASER-BASED UNDERWATER LOCATION DETECTION ASSEMBLY AND METHOD

TECHNICAL FIELD

The present invention relates to a location detection system to determine the location and depth of the underwater systems.

STATE OF THE ART

Wireless or ultrasonic communication methods known for the communication purposes in the underwater systems are used. In case of any error (sinking, drifting, getting lost etc.) the locations of the underwater vehicles and their depth that cannot be determined can be used, only if the conventional systems can be kept activated. In case of getting lost underwater, rescue operations may last for a long time.

In the patent numbered JPH04103232A, communication over receiver-transmitter systems requires that the positions of the receiver-transmitter are within the direction of line of sight. Thus, the modulated data received can be detected and interpreted. In fact, in the communication modules which become products, there are movable lens/mirror systems called beam router so as to make the receiver and the transmitter to see each other.

BRIEF DESCRIPTION OF THE INVENTION

The aim of the invention is to provide the detection of location independent of the line of sight direction of the laser source in the underwater systems.

In order to achieve said aims, the invention comprises an underwater location detection assembly for the underwater system that comprises a casing provided on an underwater body and having a laser transmissive section. The underwater location assembly comprises a laser source that is adjusted to an output power value predetermined in an indicator form with a laser beam refraction that progresses under the water on the surface of the water body in which the underwater body is submerged and a controller that activates the laser source in a location detection mode. In a loss mode, e.g. in case there is a loss, the laser source is activated by means of the controller when an alarm protocol is started. The laser source is aligned to the surface directly or indirectly with the mirror. Thus, the laser beam reaches the surface. The laser beam that reaches the surface refracts on the water surface by means of the sufficient power of the laser source such that it forms an indicator. The indicator is detected by means of a scanner that scans the water surface and the location of the underwater body is determined visually.

The main factor of the invention is based on the principle that the laser beams formed with the laser source in the underwater system first travels in the water/sea and then reaches to the water surface. The location of the underwater system is detected by means of interpreting the laser signals which reach the surface of the water. It is known that laser beams can travels in different mediums. The travel of the laser beams, the data transmission capabilities vary according to the medium type and the laser wavelength. Refractions and reflections occur according to the density differences in the transitions between these mediums. The subject of the invention allows for achieving an indicator which can be interpreted on the water by making use of the refraction of the laser beam that comes from the laser source. In addition to the refractions, reflections also strengthen the indicator.

In a preferred embodiment of the invention, laser transmissive section consists of a material which is laser transmissive at a visible wave length. The laser beam transmitting through the laser transmissive section is set to the visible wavelength and the location of the underwater body is simply obtained by means of detecting the reflection of a visible light on the surface.

In a preferred embodiment of the invention, the controller comprises an inertia measurement unit, to which it is connected such that it transmits electrical signal and which is adjusted such that it detects the depth measurement of the underwater body from the surface and transmits the data to the laser source. The inertia measurement unit determines the depth information of the controller, allowing for transmitting the depth information to the surface by means of the laser source.

In a preferred embodiment of the invention, it is configured such that the depth measurement data provided by the inertia measurement unit of the controller is loaded on the laser beam with modulation. Thus, the indicator on the surface shows the depth information of the underwater body with the laser pulses. The laser modulations with standards can be used for modulation. The indicator disseminates vibration at the modulated laser beam pulse frequency, so that it is possible to determine the depth of the underwater body by the laser pulse reader for example with a scanner. In a preferred embodiment of the invention, the controller comprises a modulator which is adjusted such that the depth measurement data of the laser source is loaded on the laser beam. Thus, the process is realized by the modulator without requiring the controller to use its sources for the modulation.

In a preferred embodiment of the invention, the modulator configures the laser beam in the form of encryptions with the predetermined encoding algorithm. This may not only be realized by means of software compiled by the controller but also be realized by means of an encryption unit with which the modulator communicates. The encoded information allows, for example to be detected only by the ally troops that perform surface scanning of the location information of a military submarine.

In a preferred embodiment of the invention, the laser source comprises a blue-green laser unit. Surprisingly, the blue-green laser both fulfills the high data transmission requirements in the modulation mode and has refraction and scattering performance that forms an indicator that can be detected easily at high depths.

In a preferred embodiment of the invention, it comprises an adjacent auxiliary laser source facing the laser transmissive portion such that it provides at least one first light beam and at least one second light beam that forms a separation angle provided by the laser source. The auxiliary laser source allows for detecting the depth of the underwater vehicle by using basic geometry formulas with two indicators provided on the surface without requiring even a modulation. In a preferred embodiment of the invention, the separation angle is selected less than 30°. Therefore, when the depth of the underwater vehicle is more, the scanning area of the first indicator and the second indicator respectively is narrowed by means of the laser source and the auxiliary laser source.

In a preferred embodiment of the invention, the separation angle is adjusted such that the first light beam and the second light beam are enabled to hit near the mutual edges of the laser transmissive section.

In a preferred embodiment of the invention, the separation angle is adjusted such that the first light beam and the second light beam are enabled to hit near the center of the laser transmissive section.

In order to achieve said aims, a preferred embodiment of the invention comprises an underwater location detection method for the underwater system that comprises a casing provided on an underwater body and having a laser transmissive section. The location detection method also comprises the following process steps; aligning a laser source positioned in the casing through the laser transmissive section to the surface of a water body in which the underwater body is submerged; activating the laser source in a location detection mode by the controller to which it is connected such that it transmits electrical signal; forming an indicator with a refraction on the surface by moving the laser source under water which is adjusted to a predetermined output power value. These process steps provide transmitting the location information to the surface by operating the laser source by means of the controller for example in a loss mode or alarm mode of the underwater body. Accordingly, the laser transmissive section can be aligned with the section of the underwater vehicle facing the surface. Alternatively, it is possible to distribute a plurality of laser transmissive surfaces such that they face different sections of the underwater vehicle. In this case, it can be ensured that a laser beam corresponding to the surface can form one or more indicator by means of scattering laser beam of the laser source (laser generator or mirrors that dissipate the laser beam coming from the laser generator) corresponding to the laser transmissive sections in the section facing the surface or in all directions depending on the situation. The laser transmissive part can be provided on each surface and also can be provided on a single surface for example distributed in a circular direction. Therefore, in cases where it is not required to carry out maneuver or is required less maneuvers, the possibility of accessing the surface with the laser beam is increased.

A preferred embodiment of the invention comprises the following process steps; detecting the depth of the underwater body from the surface by an inertia measurement unit of the controller; modulating the modulator of the controller such that the laser beam contains the detected depth measurement data. Therefore, the depth information of the underwater body can be achieved by means of the indicator formed on the surface. The indicator can be read with e.g. eyes or camera and image processing technologies etc. which is a receiver appropriate to the wavelength of the indicator.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is an illustrative front schematic view of the embodiment of the inventive underwater location detection assembly with a single laser source where the controller is enlarged.

Figure 2 is a schematic view of the illustrative embodiment of the inventive underwater location detection assembly with double laser source where the laser sources are adjusted such that they face away from each other. Figure 3 is a schematic view of the illustrative embodiment of the inventive underwater location detection assembly with double laser source where the laser sources are adjusted such that they coincide with each other.

DETAILED DESCRIPTION OF THE INVENTION

The subject of the invention is described without any limitation and with reference to the examples only for clarifying the subject matter in this detailed description.

In Figure 1 , an illustrative embodiment of the inventive underwater location detection assembly having a single laser source (16) which is applied to an underwater body (10) which is a submarine is shown schematically. The underwater body (10) is located for example at a depth which has a depth distance (H) in the sea from surface (22), is a water body (24) that forms border along the air above the water (30) and a surface (22). There is a casing (12) on the underwater body (10). A laser transmissive section (14) is provided on the external wall of the casing (12). The laser transmissive section (14) is a transparent plate which transmits the blue- green laser beam (40). A blue-green laser source (16) is fixed into the casing (12) in a distanced manner with the laser transmissive section (14). A controller (11) which comprises a central processing unit (114), an inertia measurement unit (112), a laser driver (116) and a modulator (118) is connected with a laser source (16) such that it transmits signal. The example specification of the laser source (16) is presented herein in the following table.

Table 1 Laser source specification

The laser transmissive section (14) is located on the upper portion of the underwater body (10) that faces the surface (22). When location detection is required for the underwater body (10) by an external observer, the controller (11) is adjusted to a location detection mode. In this case, the central processing unit (114) enables the depth distance (H) determined by the inertia measurement unit (112) to be distributed as a laser beam (40) of the laser driver (116) comprising pulse with the help of the modulator (118). The modulator (118) enables to form a laser beam (40) in an encrypted form by encoding the data with an encryption algorithm. The laser transmissive section (14) at the visible wavelength enables the laser beam (40) to rise up to the surface (22) as a visible first light beam (46). The first light beam (46) forms an intrasystem section (42) from the laser source (16) to the laser transmissive section (14) and then it reaches to the visible wavelength at the laser transmissive section (14) and it exceeds the water body (24) of the underwater section (44) along the depth distance (H). The laser beam (40) is refracted and scattered because of the passage from salt water to air on the surface (22) between the above water (30) and underwater (20). Therefore, an indicator (45) from a laser beam (40) is formed on the surface (22). In the continuation of the indicator (45), the laser beam (40) rises up to the sky. Because the indicator (45) formed with the scattering and refraction of the laser beam (40) on the surface (22) has a visible wavelength, it can be detected by an observer on the surface (22).

In Figure 2, an alternative embodiment wherein two laser sources (16,17) are used are shown schematically. Here, the laser source (16) is aligned towards an edge of the laser transmissive section (14). An auxiliary laser source (17) is aligned in the casing (12) at the opposite edge of the laser transmissive section (14) such that there is a separation angle (a) between them. The separation angle (a) is selected less than 30° in the example shown. When the first light beam (46) forms the first indicator (45), the auxiliary laser source (17) at a distance from thereof, provides a second light beam (48) that forms a second indicator (47). Both of the laser sources (16, 17) have similar structures and they generate blue-green laser. In the location detection mode, the controller (11) operates both laser sources (16, 17) together. Therefore, the first indicator (45) and the second indicator (47) occur on the surface (22) simultaneously. Since an observer knows the separation angle (a), he/she can calculate the depth of the underwater body (10) on the basis of the distance between the locations of both indicators (45, 47). Therefore, the depth of the underwater body (10) can be detected even if there is no modulator (118) or it is deactivated.

In Figure 3, the laser sources (16, 17) are fixed into the casing (12) with a separation angle (a) such that they are facing each other. The separation angle (a) enables the first light beam (46) and the second light beam (47) to focus firstly in the laser transmissive section (14) and to separate from each other. Similar to the system given in Figure 2, the depth distance (H) can be calculated with separation angle (a) and the distance between the first indicator (45) and the second indicator (47) that are formed by the first and second light beam (46, 48). The power of the laser sources (16, 17) is determined as 1W and above. REFERENCE NUMBERS

10 Underwater body 24 Water body

11 Controller 30 Above water

112 Inertia measuring unit 40 Laser beam 114 Central processor unit 42 Intrasystem section 116 Laser driver 44 Underwater section 118 Modulator 45 First indicator

12 Casing 46 First light beam

14 Laser transmissive section 47 Second indicator

16 Laser source 48 Second light beam

17 Auxiliary laser source a Separating angle 20 Underwater H Depth distance

22 Surface P Output power value

Claims

1 - An underwater location detection assembly for an underwater system which is provided on an underwater body (10) and comprises a casing (12) having a laser transmissive section (14), characterized in that it comprises a laser source (16) which is adjusted to a predetermined power output value (P) with the refraction of a laser beam (40) travelling underwater (20) on the surface (22) of the water body (24) in which the underwater body (10) is submerged such that it forms an indicator (45), and is positioned in a casing (12) by being aligned to the laser transmissive section (14) and a controller (11) which activates the laser source (16) in a location detection mode.

2- An underwater location detection assembly according to Claim 1 , wherein the laser transmissive section (14) consists of a laser transmissive material at a visible wavelength.

3- An underwater location detection assembly according to any of the preceding claims, wherein the controller (11) comprises an inertia measurement unit (112) to which is connected such that it transmits electrical signal and which is adjusted to detect the depth measurement (H) of the underwater body (10) from the surface (22) and supplies the data to the laser source (16).

4- An underwater location detection assembly according to Claim 3, wherein the controller (11) is configured such that the depth measurement (H) data supplied by the inertia measurement unit (112) is loaded on the laser beam (40) by modulation.

5- An underwater location detection assembly according to Claim 3 or 4, wherein the controller (11) comprises a modulator (118) which is adjusted to load the depth measurement (H) data of the laser source (16) on the laser beam (40).

6- An underwater location detection assembly according to Claim 5, wherein the modulator (118) is configured to encrypt the laser beam (40) with a predetermined encoding algorithm.

7- An underwater location detection assembly according to any of the preceding claims, wherein the laser source (16) comprises blue-green laser unit.

8- An underwater location detection assembly according to any of the preceding claims, wherein it comprises an adjacent auxiliary laser source (17) facing the laser transmissive section (14) such that it provides at least a first light beam (46) and at least a second light beam (48) that forms a separation angle (a) provided by the laser source (16).

9- An underwater location detection assembly according to Claim 8, wherein the separation angle (a) is selected less than 30°.

10- An underwater location detection assembly according to Claim 8 or 9, wherein the separation angle (a) is adjusted such that the first light beam (46) and the second light beam (48) are enabled to hit near the mutual edges of the laser transmissive section (14).

11- An underwater location detection assembly according to any of claims 8 to 10, wherein the separation angle (a) is adjusted such that the first light beam (46) and the second light beam (48) are enabled to hit near the center of the laser transmissive section (14).

12- An underwater location detection method for an underwater system which is provided on an underwater body (10) and comprises a casing (12) having a laser transmissive section (14), characterized by comprising following process steps of aligning a laser source (16) positioned in the casing (12) through the laser transmissive section (14) to the surface (22) of a water body (24) in which the underwater body (10) is submerged; activating the laser source (16) in a location detection mode by the controller (11) to which it is connected such that it transmits electrical signal; forming an indicator (45) with a refraction on the surface (22) by moving the laser source (16) under water (20) which is adjusted to a predetermined output power value (P).

13- An underwater location detection method according to Claim 12, characterized by comprising following process steps of detecting the depth measurement (H) of the underwater body (10) from the surface (22) by an inertia measurement unit (112) of the controller (11); modulating the modulator (118) of the controller (11) such that the laser beam (40) contains the detected depth measurement (H) data.