Ocean diffraction surveys for small target detection

Abstract

A seabed target detection system is provided. The system may include a receiver array. The receiver array may include a plurality of receivers arranged on a plurality of streamers. The plurality of streamers may include a central port streamer, a central starboard streamer, an auxiliary port streamer, and an auxiliary starboard streamer. The system may include a source array. The source array may include a plurality of sources. The plurality of sources may include a central port source, a central starboard source, an auxiliary port source, and an auxiliary port streamer.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. Patent Application No. 16 / 446,376, filed on June 19, 2019, the entire contents of which are incorporated herein by reference. Background Art

[0003] Seismic or other operations performed on a piece of land may identify features or characteristics beneath the subsurface of the land being analyzed. Summary of the invention

[0004] At least one aspect of the present disclosure relates to a seafloor target detection system that may include a receiver array. The receiver array may include a plurality of receivers. The plurality of receivers may receive diffraction data diffracted from a target in the seafloor. The plurality of receivers may be disposed on a plurality of streamers. The plurality of streamers may include a central streamer pair. The central streamer pair may include a central port streamer and a central starboard streamer. The plurality of streamers may include at least one auxiliary port streamer at a first distance from the central streamer pair. The plurality of streamers may include at least one auxiliary starboard streamer at a second distance from the central streamer pair, the at least one auxiliary starboard streamer being opposite to the at least one auxiliary port streamer. The seafloor target detection system may include a source array, the source array may include a plurality of sources. The plurality of sources may generate source emissions. The plurality of sources may include at least one central source pair. The at least one central source pair may include a central port source and a central starboard source. The central source pair may be located between the central streamer pair. The plurality of sources may include at least one auxiliary port source. The at least one auxiliary port source may be located between the central port streamer and the at least one auxiliary port streamer. The plurality of sources may include at least one auxiliary starboard source. The at least one auxiliary starboard source may be located between the central starboard streamer and the at least one auxiliary starboard streamer.

[0005] At least one aspect of the present disclosure relates to a method for detecting a seafloor target. The method may include providing a receiver array. The receiver array may include a plurality of receivers. The plurality of receivers may receive diffraction data diffracted from a target in the seafloor. The plurality of receivers may be disposed on a plurality of streamers. The plurality of streamers may include a central streamer pair. The central streamer pair may include a central port streamer and a central starboard streamer. The plurality of streamers may include at least one auxiliary port streamer at a first distance from the central streamer pair. The plurality of streamers may include at least one auxiliary starboard streamer located at a second distance from the central streamer pair, the at least one auxiliary starboard streamer being opposite to the at least one auxiliary port streamer. The method may include providing a source array. The source array may include a plurality of sources. The plurality of sources may generate source emissions. The plurality of sources may include at least one central source pair. The at least one central source pair may include a central port source and a central starboard source. The at least one central source pair may be located between the central streamer pair. The plurality of sources may include at least one auxiliary port source. The at least one auxiliary port source may be located between the central port streamer and the at least one auxiliary port streamer. The plurality of sources may include at least one auxiliary starboard source. The at least one auxiliary starboard source may be located between the central starboard streamer and the at least one auxiliary starboard streamer. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, drawings, and claims.

[0007] Figure 1 A seabed target detection system according to example embodiments is illustrated.

[0008] Figure 2 Diffraction surveying according to example embodiments is illustrated.

[0009] Figure 3 A reflection survey according to an example embodiment is illustrated.

[0010] Figure 4 A seabed target detection system according to example embodiments is illustrated.

[0011] Figure 5 A seabed target detection system according to example embodiments is illustrated.

[0012] Figure 6 A seabed target detection system according to example embodiments is illustrated.

[0013] Figure 7 A seabed target detection system according to example embodiments is illustrated.

[0014] Figure 8 A seabed target detection system according to example embodiments is illustrated.

[0015] Fig. 9 A method for detecting a seabed target according to an example embodiment is illustrated.

[0016] Like reference numbers and designations in the several drawings indicate like elements. DETAILED DESCRIPTION

[0017] Reflection-based surveys can obtain information about underground features. Acoustic signals can be reflected from underground lithological formations and acquired, analyzed, and interpreted. However, reflection-based surveys typically cover narrow areas and collect sparse data sets, both of which are factors that increase the time required to complete the survey. In addition, due to the resolution capabilities of reflection-based surveys, small shallow targets such as boulders buried in the seafloor may be difficult to accurately image. These small targets can complicate or delay the placement of wind turbines, marine or submarine structures fixed to the seafloor, and cable connections and communication lines between these wind turbines, marine or submarine structures.

[0018] The present disclosure relates to systems and methods for seafloor target detection. Due to the limitations of reflection-based surveys, detecting small shallow targets in the seafloor can be challenging. Without providing an accurate map of seafloor obstructions, inefficiencies associated with increased survey times (such as greater risk of weather delays) can increase the operating costs of these surveys. The systems and methods of the present disclosure can address these and other problems associated with performing surveys to detect seafloor targets.

[0019] The present disclosure relates to systems and methods for seabed target detection. For example, a seabed target detection system can provide an accurate map of seabed obstacles. The system can include a receiver array. The receiver array can include multiple receivers arranged on multiple streamers. The multiple streamers can include a central port streamer, a central starboard streamer, an auxiliary port streamer, and an auxiliary starboard streamer. The system can include a source array. The source array can include multiple sources. The multiple sources can include a central port source, a central starboard source, an auxiliary port source, and an auxiliary port streamer.

[0020] Figure 1An example seabed target detection system 100 for an ocean environment is illustrated, in which the systems and methods of the present disclosure can perform seismic surveys to detect seabed targets. The seabed target detection system 100 may include a receiver array 105. The receiver array 105 may include a plurality of receivers 110. The plurality of receivers 110 may be disposed on a plurality of streamers 115. One of the streamers 115 may be a cable (e.g., a surface cable), a wire assembly, or any component capable of connecting a receiver to a recording device that may be located on a vessel 102. The receiver array 105 may include one or more receivers. For example, the receiver array 105 may include a plurality of receivers 110 coupled to a plurality of streamers 115. The receiver array 105 may include a pattern of receivers. For example, a plurality of receivers 110 may be coupled to a plurality of streamers 115 along a line. The plurality of receivers 110 in the receiver array 105 may be coupled to the plurality of streamers 115 in a grid pattern. The receiver array 105 may be a pattern formed by a plurality of receivers 110 disposed on the plurality of streamers 115. For example, the receiver array 105 may include a plurality of receivers 110 disposed along the plurality of streamers 115. The receiver array 105 may include a plurality of receivers 110 disposed on several of the plurality of streamers 115. The receiver array 105 may receive diffraction data diffracted from a target in the seafloor.

[0021] The receiver array 105 may include a plurality of receivers 110. The plurality of receivers 110 may receive diffraction data diffracted from a target in the seafloor. For example, the receivers in the plurality of receivers 110 may be hydrophones or any other device capable of collecting seismic data. The seismic data may include reflection data indicating underground features of the seafloor. The seismic data may include diffraction data indicating underground features of the seafloor. The underground features of the seafloor may include small shallow targets such as boulders. The width of the small shallow targets may be between 10 cm and 100 cm (e.g., 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, 100 cm). The small shallow targets may be larger than 100 cm. These small shallow targets may be smaller than 10 cm. The plurality of receivers 110 may be configured to detect sound waves reflected by seafloor targets. The plurality of receivers 110 may be configured to detect sound waves diffracted by seafloor targets. The plurality of receivers 110 may detect diffraction data diffracted from the edge of the target. For example, multiple receivers 110 can detect diffraction data originating from the edge of a large target. The volume of a large target can be between 100 and 500 cubic meters (e.g., 100 cubic meters, 200 cubic meters, 300 cubic meters, 400 cubic meters, 500 cubic meters). The volume of a large target can be less than 100 cubic meters. The volume of a large target can be greater than 100 cubic meters. A large target can be a shipping container. Diffraction data can originate from the corner of a shipping container. Multiple receivers 110 can detect targets with irregular surface features. For example, multiple receivers 110 can detect targets with small faces, edges, sharp boundaries, or textures. A seabed target can be completely buried in the seabed. A seabed target can be partially buried in the seabed.

[0022] The plurality of streamers 115 may include a central streamer pair. The central streamer pair may include a central port streamer 125 and a central starboard streamer 130. The central port streamer 125 may be a cable (e.g., a surface cable), a wire assembly, or any component capable of connecting a receiver to a recording device that may be located on the vessel 102. The recording device may receive data such as reflection and diffraction data from the plurality of receivers 110 disposed on the plurality of streamers 115. The central port streamer 125 may be disposed on the port side of the vessel 102. The central starboard streamer 130 may be a cable (e.g., a surface cable), a wire assembly, or any component capable of connecting a receiver to a recording device that may be located on the vessel 102. The central starboard streamer 130 may be disposed on the starboard side of the vessel 102.

[0023] The plurality of streamers 115 may include an auxiliary port streamer 135. The auxiliary port streamer 135 may be positioned at a first distance from the central streamer pair. For example, the auxiliary port streamer 135 may be located at a first distance from the central port streamer 125. The auxiliary port streamer 135 may be located at a first distance from the central starboard streamer 130. The first distance may include a distance between 5 meters and 30 meters. For example, the first distance may be 12.5 meters. The first distance may be less than 5 meters. The first distance may be greater than 30 meters. The auxiliary port streamer 135 may be a cable (e.g., a surface cable), a wire assembly, or any component capable of connecting a receiver to a recording device that may be located on the vessel 102. The auxiliary port streamer 135 may be disposed on the port side of the vessel 102. The plurality of streamers 115 may include several auxiliary port streamers 135. For example, the plurality of streamers 115 may include one, two, three, or more auxiliary port streamers 135.

[0024] The plurality of streamers 115 may include an auxiliary starboard streamer. The auxiliary starboard streamer 140 may be located at a second distance from the central streamer pair. For example, the auxiliary starboard streamer 140 may be located at a second distance from the central port streamer 125. The auxiliary starboard streamer 140 may be located at a second distance from the central starboard streamer 130. The second distance may include a distance between 5 meters and 30 meters. For example, the second distance may be 12.5 meters. The second distance may be less than 5 meters. The second distance may be greater than 30 meters. The second distance may be approximately the same as the first distance. The auxiliary starboard streamer 140 may be a cable (e.g., a surface cable), a wire assembly, or any component capable of connecting a receiver to a recording device that may be located on the vessel 102. The auxiliary starboard streamer 140 may be disposed on the starboard side of the vessel 102. The auxiliary starboard streamer 140 may be located opposite the auxiliary port streamer 135. The plurality of streamers 115 may include several auxiliary starboard streamers 140. For example, the plurality of streamers 115 may include one, two, three, or more auxiliary starboard streamers 140. The plurality of streamers 115 may include exactly eight streamers. For example, the plurality of streamers 115 may include one central port streamer 125, one central starboard streamer 130, three auxiliary port streamers 135, and three auxiliary starboard streamers 140.

[0025] The seabed target detection system 100 may include a source array 127. The source array 127 may include a plurality of sources. The plurality of sources may include a central port source 150, a central starboard source 155, an auxiliary port source 160, and an auxiliary starboard source 165. A source in the plurality of sources may generate source emissions. A source in the plurality of sources may generate acoustic waves. The source array 127 may generate acoustic signals to be received by the receiver array 105. For example, the source array 127 may include a plurality of sources coupled to a source cable 197. The source array may include a pattern of sources. The source may include a central port source 150, a central starboard source 155, an auxiliary port source 160, and an auxiliary starboard source 165. For example, the central port source 150, the central starboard source 155, the auxiliary port source 160, and the auxiliary starboard source 165 may be coupled to a source cable 197 to form the source array 127.

[0026] Source array 127 may include at least one central source pair. Source array 127 may include a central source pair. The central source pair may include a central port source 150 and a central starboard source 155. The central source pair may be located between the central streamer pair. For example, central port source 150 may be located between central port streamer 125 and central starboard streamer 130. Central port source 150 may generate source emissions. Central port source 150 may generate acoustic waves. Central port source 150 may generate acoustic waves that will be reflected by a seafloor target and received by a plurality of receivers 110. Central port source 150 may generate acoustic waves that will be diffracted by a seafloor target and received by a plurality of receivers 110. Central starboard source 155 may be located between central port streamer 125 and central starboard streamer 130. Central starboard source 155 may generate source emissions. Central starboard source 155 may generate acoustic waves. Central starboard source 155 may generate acoustic waves that will be reflected by a seafloor target and received by a plurality of receivers 110. The central starboard source 155 may generate acoustic waves that will be diffracted by the seafloor target and received by the plurality of receivers 110 .

[0027] The source array 127 may include at least one auxiliary port source 160. The source array may include the auxiliary port source 160. The auxiliary port source 160 may be located between the central port streamer 125 and the auxiliary port streamer 135. The auxiliary port source 160 may be located between the first auxiliary port streamer 135 and the second auxiliary port streamer 135. The auxiliary port source 160 may generate source emissions. The auxiliary port source 160 may generate sound waves. The auxiliary port source 160 may generate sound waves that will be reflected by the seabed target and received by the plurality of receivers 110. The auxiliary port source 160 may generate sound waves that will be diffracted by the seabed target and received by the plurality of receivers 110. The source array 127 may include a plurality of auxiliary port sources 160. For example, the source array 127 may include one, two, three, or more auxiliary port sources 160.

[0028] The source array 127 may include at least one auxiliary starboard source 165. The auxiliary starboard source 165 may be located between the central starboard streamer 130 and the auxiliary starboard streamer 140. The auxiliary starboard source 165 may be located between the first auxiliary starboard streamer 140 and the second auxiliary starboard streamer 140. The auxiliary starboard source 165 may generate source emissions. The auxiliary starboard source 165 may generate acoustic waves. The auxiliary starboard source 165 may generate acoustic waves that will be reflected by the seabed target and received by the plurality of receivers 110. The auxiliary starboard source 165 may generate acoustic waves that will be diffracted by the seabed target and received by the plurality of receivers 110. The source array 127 may include a plurality of auxiliary starboard sources 165. For example, the source array 127 may include one, two, three or more auxiliary starboard sources 165. The plurality of sources may include exactly eight sources. For example, the plurality of sources may include one central port source 150, one central starboard source 155, three auxiliary port sources 160, and three auxiliary starboard sources 165.

[0029] The seabed target detection system 100 may include a port deflector 170. The port deflector 170 may be a deflector, downwind vane, or deflector that laterally redirects the movement of water through the deflector to generate a certain amount of lateral force. The deflector may be configured to redirect the flow of water through the deflector relative to the direction of movement of the deflector through the water. The deflector may include a steering device associated with the deflector. The steering device may redirect the flow of water to control the amount of lateral force generated by the deflector. The port deflector 170 may be connected to the starboard deflector 175 via a cable. The cable may include a streamer cable 195. For example, the port deflector 170 may be directly connected or coupled to the streamer cable 195. The port deflector 170 may be connected or coupled to the streamer cable 195 via a coupling device or a secondary cable. The coupling device may couple the port deflector 170 to the streamer cable 195. The streamer cable 195 may be connected to a plurality of streamers 115. The plurality of streamers 115 may be connected or coupled to the streamer cable 195 via a coupling device or a secondary cable. The coupling device may couple the streamer cable 195 to the plurality of streamers 115.

[0030] The seabed target detection system 100 may include a starboard deflector 175. The starboard deflector 175 may be a deflector, downwind vane, or deflector that laterally redirects the movement of water through the deflector to generate a certain amount of lateral force. The deflector may be configured to redirect the flow of water through the deflector relative to the direction of movement of the deflector through the water. The deflector may include a steering device associated with the deflector. The steering device may redirect the flow of water to control the amount of lateral force generated by the deflector. The starboard deflector 175 may be connected to the port deflector 170 via a cable. The cable may include a streamer cable 195. For example, the starboard deflector 175 may be directly connected or coupled to the streamer cable 195. The starboard deflector 175 may be connected or coupled to the streamer cable 195 via a coupling device or a secondary cable. The coupling device may couple the starboard deflector 175 to the streamer cable 195. The streamer cable 195 may be connected to a plurality of streamers 115. The plurality of streamers 115 may be connected or coupled to the streamer cable 195 via a coupling device or a secondary cable. The coupling device may couple the streamer cable 195 to the plurality of streamers 115.

[0031] The seafloor target detection system 100 may include a vessel 102. The vessel 102 may tow a receiver array 105. The vessel 102 may tow a source array 127. The vessel 102 may tow the source array 127 in front of the receiver array 105. The vessel 102 may be connected to a port deflector 170. The vessel 102 may be connected to the port deflector 170 via a port cable 180. The vessel 102 may be coupled to the port deflector 170. The vessel 102 may be coupled to the port deflector 170 via a port cable 180. The port cable 180 may be a surface cable, an electrical wiring assembly, or any component capable of connecting a receiver to a recording device that may be located on the vessel 102. The port cable 180 may be a power cable that transmits power from the vessel 102 to a plurality of sources or a plurality of receivers 110. The vessel 102 may be connected to a starboard deflector 175. The vessel 102 may be connected to the starboard deflector 175 via a starboard cable 185. The vessel 102 may be coupled to the starboard deflector 175. The vessel 102 may be coupled to the starboard deflector 175 via a starboard cable 185. The starboard cable 185 may be a surface cable, an electrical wiring assembly, or any component capable of connecting a receiver to a recording device that may be located on the vessel 102. The starboard cable 185 may be a power cable that transmits power from the vessel 102 to a plurality of sources or a plurality of receivers 110. The vessel 102 may tow the receiver array 105 and the source array 127 so that the receiver array 105 receives diffraction data diffracted from a target in the seafloor. The diffraction data diffracted from a target in the seafloor may include diffraction waves generated by the source array 127. The source array 127 may generate an acoustic signal to diffract from a target in the seafloor.

[0032] The seabed target detection system 100 may include a streamer cable 195. The streamer cable 195 may connect the port deflector 170 to the starboard deflector 175. The streamer cable may be a surface cable, a wire assembly, or any component capable of connecting a receiver to a recording device that may be located on the vessel 102. The streamer cable 195 may be coupled to the port deflector 170. The streamer cable 195 may be coupled to the starboard deflector 175. The streamer cable 195 may be several cables. For example, the streamer cable 195 may be several cables coupled together to form a longer cable. The streamer cable 195 may be connected to the central port streamer 125. The streamer cable 195 may be connected to the central starboard streamer 130. The streamer cable 195 may be connected to the auxiliary port streamer 135. The streamer cable 195 may be connected to the auxiliary starboard streamer 140.

[0033] The streamer cables 195 may be power cables that transmit power from the vessel 102 to the plurality of receivers 110. The streamer cables 195 may transmit power from the vessel 102 to receivers disposed on the central port streamer 125. The streamer cables 195 may transmit power from the vessel 102 to receivers disposed on the central starboard streamer 130. The streamer cables 195 may transmit power from the vessel 102 to receivers disposed on the auxiliary port streamer 135. The streamer cables 195 may transmit power from the vessel 102 to receivers disposed on the auxiliary starboard streamer 140.

[0034] The seabed target detection system 100 may include a source cable 197. The source cable 197 may connect the port cable 180 to the starboard cable 185. The source cable 197 may be coupled to the port cable 180 closer to the port deflector 170 than the vessel 102. The source cable 197 may be coupled to the starboard cable 185 closer to the starboard deflector 175 than the vessel 102. The source cable 197 may be directly connected or coupled to the port cable 180. The source cable 197 may be directly connected or coupled to the starboard cable 185. The source cable 197 may be connected to the source array 127. The source cable 197 may be directly connected or coupled to the source array 127. The source cable 197 may be connected to the central port source 150. The source cable 197 may be connected to the central starboard source 155. The source cable 197 may be connected to the auxiliary port source 160. The source cable 197 may be connected to the auxiliary starboard source 165. Source cable 197 may be connected to central port source 150 via a secondary cable. Source cable 197 may be connected to central starboard source 155 via a secondary cable. Source cable 197 may be connected to auxiliary port source 160 via a secondary cable. Source cable 197 may be connected to auxiliary starboard source 165 via a secondary cable.

[0035] The source cable 197 may be a power cable that transmits power from the vessel 102 to a plurality of sources. The source cable 197 may transmit power from the vessel 102 to the central port source 150. The source cable 197 may transmit power from the vessel 102 to the central starboard source 155. The source cable 197 may transmit power from the vessel 102 to the auxiliary port source 160. The source cable 197 may transmit power from the vessel 102 to the auxiliary starboard source 165.

[0036] The seabed target detection system 100 may include a plurality of power streamers 190. The power cables 190 may include cables for transmitting power. The power cables 190 may transmit power from the vessel 102 to a plurality of sources of the source array 127. The power cables 190 may transmit power from the vessel 102 to the central port source 150. The power cables 190 may transmit power from the vessel 102 to the central starboard source 155. The power cables 190 may transmit power from the vessel 102 to the auxiliary port source 160. The power cables 190 may transmit power from the vessel 102 to the auxiliary starboard source 165.

[0037] Figure 2Diffraction survey 200 is illustrated. Diffraction survey 200 may include receiver array 105 and source array 127. Source array 127 may generate source emission 215. Source emission 215 may pass through a medium (e.g., seawater) and diffract from seafloor target 210. Seafloor target 210 may be completely buried in seafloor 220. Seafloor target 210 may be partially buried in seafloor 220. Seafloor target 210 may include small shallow targets such as boulders. Small shallow targets may have a width between 10 cm and 100 cm (e.g., 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, 100 cm). Small shallow targets may be larger than 100 cm. These small shallow targets may be smaller than 10 cm. Waves diffracted from seafloor target 210 may include diffraction data. Diffraction data may include diffraction waves 205. Receiver array 105 may receive diffraction data. For example, the receiver array 105 may receive the diffraction wave 205. The plurality of receivers 110 in the receiver array 105 may receive the diffraction data. For example, the plurality of receivers 110 may receive the diffraction wave 205. The receivers in the plurality of receivers 110 may receive the diffraction wave 205. The diffraction data may include the diffraction wave 205 originating from the seafloor target. The diffraction data may include the diffraction wave 205 generated from the source emission 215. The plurality of receivers 110 may detect the diffraction data diffracted from the edge of the target. For example, the plurality of receivers 110 may detect the diffraction data originating from the edge of a large target. The volume of the large target may be between 100 and 500 cubic meters (e.g., 100 cubic meters, 200 cubic meters, 300 cubic meters, 400 cubic meters, 500 cubic meters). The volume of the large target may be less than 100 cubic meters. The volume of the large target may be greater than 100 cubic meters. The large target may be a shipping container. The diffraction data may originate from the corner of the shipping container. The plurality of receivers 110 can detect targets having irregular surface features. For example, the plurality of receivers 110 can detect targets having small faces, edges, sharp boundaries, or textures.

[0038] A plurality of receivers 110 in the receiver array 105 may receive diffraction data. The diffraction data may include diffraction waves 205 diffracted from a seafloor target that is smaller than the Fresnel zone. The Fresnel zone is a reflection region from which most of the reflected energy returns, and the arrival time of the reflection differs from the arrival time of the energy propagated from the energy source by less than half a cycle. Waves with such arrival times may constructively interfere and be detected by a single arrival. Therefore, it may be difficult to detect reflected waves from a target that is smaller than the Fresnel zone. However, the plurality of receivers 110 of the receiver array 105 may detect diffraction waves from a target that is smaller than the Fresnel zone.

[0039] Source array 127 may generate acoustic waves. The acoustic waves may include source emission 215. The acoustic waves may be diffracted from a target in the seafloor. Receiver array 105 may receive diffracted waves originating from a target in the seafloor. A central source pair may generate acoustic waves. Central port source 150 may generate acoustic waves. Central starboard source 155 may generate acoustic waves. Auxiliary port source 160 may generate acoustic waves. Auxiliary starboard source 165 may generate acoustic waves. Receivers in a plurality of receivers 110 in receiver array 105 may receive diffracted waves. Receivers disposed on central port streamer 125 may receive diffracted waves. Receivers disposed on central starboard streamer 130 may receive diffracted waves. Receivers disposed on auxiliary port streamers 135 may receive diffracted waves. Receivers disposed on auxiliary starboard streamers 140 may receive diffracted waves.

[0040] Figure 3 Diffraction survey 300 is illustrated. Reflection survey 300 may include receiver array 105 and source array 127. Source array 127 may generate source emission 215. Source emission 215 may pass through a medium (e.g., seawater) and reflect from seafloor target 210. Seafloor target 210 may be completely buried in seafloor 220. Seafloor target 210 may be partially buried in seafloor 220. Seafloor target 210 may include small shallow targets such as boulders. Small shallow targets may have a width between 10 cm and 100 cm (e.g., 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, 100 cm). Small shallow targets may be larger than 100 cm. These small shallow targets may be smaller than 10 cm. Waves reflected from seafloor target 220 may include reflection data. Reflection data may include reflection wave 305. Receiver array 105 may receive reflection data. For example, receiver array 105 may receive reflection wave 305. Receivers in the plurality of receivers 110 may receive reflected waves 305. Reflection data may include reflected waves 305 originating from a target on the seafloor. Reflection data may include reflected waves 305 generated from source transmission 215. The plurality of sources of source array 127 may generate acoustic signals. The plurality of receivers 110 in receiver array 105 may receive reflection data reflected from a target in the seafloor. Reflection data may include reflected waves 305. Receivers in the plurality of receivers 110 may receive reflected waves 305 reflected from a target in the seafloor and generated by a source in the plurality of sources in source array 127.

[0041] Figure 4 The subsea target detection system 100 is illustrated. The subsea target detection system 100 may include a source array 127 and a receiver array 105. The source array 127 may generate a first source emission 405. The source array 127 may generate a second source emission 415. The source array 127 may generate a third source emission 425. The first source emission 405 may be emitted at an angle θ 1440 is reflected from the seafloor 220. The receiver array 105 can receive the 1 440 is a wave reflected from the seafloor 220. The receivers in the plurality of receivers 110 may receive the wave reflected from the seafloor 220 at an angle θ. 1 440 is a wave reflected from the seabed 220. The wave reflected from the seabed 220 may be the reflected wave 410. Angle θ 1 440 may be less than the reflection critical angle of the sources in source array 127 .

[0042] The second source emission 415 may be at an angle θ 2 445 is reflected from the seafloor 220. For example, the angle θ 2 445 may be a reflection critical angle of a source in source array 127. Refracted wave 420 is a wave generated from second source emission 415 instead of being reflected from seafloor 220. Critical angles may include a reflection critical angle. Critical angles may include an incidence critical angle. The incidence critical angle is the angle at which the refracted wave propagates along an interface between two media. The critical angle may depend on a distance 435 between seafloor 220 and receiver array 105. Distance 435 may be between 10 meters and 100 meters. For example, the distance may be 15 meters, 25 meters, 50 meters, or 75 meters. Distance 435 may be less than 10 meters. Distance 435 may be greater than 100 meters. Receiver array 105 does not receive radiation at angle θ. 2 445 is a wave reflected from the seafloor 220. The receivers in the plurality of receivers 110 do not receive the wave reflected at the angle θ. 2 445 waves reflected from the seabed 220. The receivers in the plurality of receivers 110 may be disposed at the critical angle of reflection of the sources in the source array 127. The receivers in the plurality of receivers 110 may be disposed at the critical angle of reflection of the sources in the plurality of sources in the source array 127. The receivers disposed at the critical angle of reflection may receive diffraction data in response to the acoustic source. The receivers disposed at the critical angle of reflection may receive diffraction data generated from the second source emission 415. The second source emission 415 may generate acoustic waves. The receivers disposed at the critical angle of reflection may receive diffraction data generated by the acoustic waves.

[0043] The third source emission 425 may be at an angle θ 3 450 is reflected from the seafloor 220. For example, the angle θ 3 450 may be greater than the critical angle of reflection of the sources in source array 127. Refracted wave 430 is a wave generated from third source emission 425 instead of being reflected from seafloor 220. Receiver array 105 does not receive the reflected wave at angle θ. 3 450 is a wave reflected from the seafloor 220. The receivers in the plurality of receivers 110 do not receive the wave reflected at the angle θ. 3450 waves reflected from the seabed 220. The receivers in the plurality of receivers 110 may be arranged outside the critical angle of reflection of the sources in the source array 127. The receivers in the plurality of receivers 110 may be arranged outside the critical angle of reflection of the sources in the plurality of sources in the source array 127. The receivers arranged outside the critical angle of reflection may receive diffraction data in response to the acoustic source. The receivers arranged outside the critical angle of reflection may receive diffraction data generated from the third source emission 425. The third source emission 425 may generate acoustic waves. The receivers arranged outside the critical angle of reflection may receive diffraction data generated by the acoustic waves.

[0044] The receiver array 105 may be disposed at a distance 435 above the seafloor 220. For example, the receiver array 105 may be disposed at 15 to 50 meters (e.g., 15, 25, 40, 50 meters) above the seafloor. The receiver array 105 may be disposed at a distance 435 less than 15 meters above the seafloor. The receiver array 105 may be disposed at a distance 435 greater than 50 meters above the seafloor. The plurality of receivers 110 in the receiver array 105 may be disposed at a distance 435 above the seafloor 220. Each of the plurality of receivers 110 may be disposed at substantially the same distance 435 above the seafloor 220. The receiver array 105 may be disposed at a distance below the sea surface. The plurality of receivers 110 in the receiver array 105 may be disposed at a distance below the sea surface. The source array 127 may be disposed at a distance above the seafloor 220. For example, the source array 127 may be disposed at 15 to 50 meters above the seafloor. The receiver array 105 may be towed deeper than the source array 127.

[0045] Figure 5 The seabed target detection system 100 is illustrated. The seabed target detection system 100 may include an auxiliary port source 160. For example, the auxiliary port source 160 may be located between the central port streamer 125 and the centerline 505 of the central port streamer 125 and the auxiliary port streamer 135. The auxiliary port source 160 may be located on the centerline 505 of the central port streamer 125 and the auxiliary port streamer 135. The auxiliary port source 160 may be located between the first auxiliary port streamer 135 and the second auxiliary port streamer 135. The auxiliary port source 160 may be located between the first auxiliary port streamer 135 and the centerline 505 of the first auxiliary port streamer 135 and the second auxiliary port streamer 135. The auxiliary port source 160 may be located between the second auxiliary port streamer 135 and the third auxiliary port streamer 135. The auxiliary port source 160 may be located between the second auxiliary port streamer 135 and a centerline 505 of the second auxiliary port streamer 135 and the third auxiliary port streamer 135 .

[0046] The seabed target detection system 100 may include an auxiliary starboard source 165. For example, the auxiliary starboard source 165 may be located between the central starboard streamer 130 and the centerline 505 of the central port streamer 125 and the auxiliary port streamer 135. The auxiliary starboard source 165 may be located on the centerline 510 of the central starboard streamer 130 and the auxiliary port streamer 140. The auxiliary starboard source 165 may be located between the first auxiliary starboard streamer 140 and the second auxiliary starboard streamer 140. The auxiliary starboard source 165 may be located between the first auxiliary starboard streamer 140 and the centerline 515 of the first auxiliary starboard streamer 140 and the second auxiliary starboard streamer 140. The auxiliary starboard source 165 may be located between the second auxiliary starboard streamer 140 and the third auxiliary starboard streamer 140. The auxiliary starboard source 165 may be located between the second auxiliary starboard streamer 140 and a centerline 515 of the second auxiliary starboard streamer 140 and the third auxiliary starboard streamer 140 .

[0047] Figure 6 An example of a subsea target detection system 100 is shown. The subsea target detection system 100 may include a receiver array 105. The receiver array 105 may include a plurality of receivers 110. The plurality of receivers 110 may be disposed on a plurality of streamers 115. The streamers in the plurality of streamers 115 may be cables (e.g., surface cables), wire assemblies, or any component capable of connecting a receiver to a recording device that may be located on the vessel 102. The receiver array 105 may include one or more receivers. For example, the receiver array 105 may include a plurality of receivers 110 coupled to the plurality of streamers 115. The receiver array 105 may include a pattern of receivers. For example, the plurality of receivers 110 may be coupled to the plurality of streamers 115 along a line. The plurality of receivers 110 in the receiver array 105 may be coupled to the plurality of streamers 115 in a grid pattern. The receiver array 105 may be a pattern formed by a plurality of receivers 110 disposed on the plurality of streamers 115. For example, the receiver array 105 may include a plurality of receivers 110 disposed along the plurality of streamers 115. Receiver array 105 may include a plurality of receivers 110 disposed on a plurality of streamers in plurality of streamers 115. Receiver array 105 may receive diffraction data diffracted from a target in the seafloor.

[0048] The receiver array 105 may include a plurality of receivers 110. The plurality of receivers 110 may receive diffraction data diffracted from a target in the seafloor. For example, the receivers in the plurality of receivers 110 may be hydrophones or any other device capable of collecting seismic data. The seismic data may include reflection data indicating underground features of the seafloor. The seismic data may include diffraction data indicating underground features of the seafloor. The underground features of the seafloor may include small shallow targets such as boulders. The width of the small shallow targets may be between 10 cm and 100 cm (e.g., 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, 100 cm). The small shallow targets may be larger than 100 cm. These small shallow targets may be smaller than 10 cm. The plurality of receivers 110 may be configured to detect sound waves reflected by seafloor targets. The plurality of receivers 110 may be configured to detect sound waves diffracted by seafloor targets. The plurality of receivers 110 may detect diffraction data diffracted from the edge of the target. For example, multiple receivers 110 can detect diffraction data originating from the edge of a large target. The volume of a large target can be between 100 and 500 cubic meters (e.g., 100 cubic meters, 200 cubic meters, 300 cubic meters, 400 cubic meters, 500 cubic meters). The volume of a large target can be less than 100 cubic meters. The volume of a large target can be greater than 100 cubic meters. The large target can be a shipping container. Diffraction data can originate from the corner of a shipping container. Multiple receivers 110 can detect targets with irregular surface features. For example, multiple receivers 110 can detect targets with small faces, edges, sharp boundaries, or textures. A seabed target can be completely buried in the seabed. A seabed target can be partially buried in the seabed.

[0049] The plurality of streamers 115 may include a central streamer pair. The central streamer pair may include a central port streamer 125 and a central starboard streamer 130. The central port streamer 125 may be a cable (e.g., a surface cable), a wire assembly, or any component capable of connecting a receiver to a recording device that may be located on the vessel 102. The recording device may receive data such as reflection and diffraction data from the plurality of receivers 110 disposed on the plurality of streamers 115. The central port streamer 125 may be disposed on the port side of the vessel 102. The central starboard streamer 130 may be a cable (e.g., a surface cable), a wire assembly, or any component capable of connecting a receiver to a recording device that may be located on the vessel 102. The central starboard streamer 130 may be disposed on the starboard side of the vessel 102.

[0050] The plurality of streamers 115 may include an auxiliary port streamer 135. The auxiliary port streamer 135 may be positioned at a first distance from the central streamer pair. For example, the auxiliary port streamer 135 may be located at a first distance from the central port streamer 125. The auxiliary port streamer 135 may be located at a first distance from the central starboard streamer 130. The first distance may include a distance between 5 meters and 30 meters. For example, the first distance may be 12.5 meters. The first distance may be less than 5 meters. The first distance may be greater than 30 meters. The auxiliary port streamer 135 may be a cable (e.g., a surface cable), a wire assembly, or any component capable of connecting a receiver to a recording device that may be located on the vessel 102. The auxiliary port streamer 135 may be disposed on the port side of the vessel 102. The plurality of streamers 115 may include several auxiliary port streamers 135. For example, the plurality of streamers 115 may include one, two, four, five, six, seven, or more auxiliary port streamers 135.

[0051] The plurality of streamers 115 may include an auxiliary starboard streamer 140. The auxiliary starboard streamer 140 may be located at a second distance from the central streamer pair. For example, the auxiliary starboard streamer 140 may be located at a second distance from the central port streamer 125. The auxiliary starboard streamer 140 may be located at a second distance from the central starboard streamer 130. The second distance may include a distance between 5 meters and 30 meters. For example, the second distance may be 12.5 meters. The second distance may be less than 5 meters. The second distance may be greater than 30 meters. The second distance may be approximately the same as the first distance. The auxiliary starboard streamer 140 may be a cable (e.g., a surface cable), a wire assembly, or any component capable of connecting a receiver to a recording device that may be located on the vessel 102. The auxiliary starboard streamer 140 may be disposed on the starboard side of the vessel 102. The auxiliary starboard streamer 140 may be located opposite the auxiliary port streamer 135. The plurality of streamers 115 may include several auxiliary starboard streamers 140. For example, the plurality of streamers 115 may include one, two, four, five, six, seven, or more auxiliary starboard streamers 140. The plurality of streamers 115 may include exactly sixteen streamers. For example, the plurality of streamers 115 may include one central port streamer 125, one central starboard streamer 130, seven auxiliary port streamers 135, and seven auxiliary starboard streamers 140.

[0052] The seabed target detection system 100 may include a port deflector 170. The port deflector 170 may be a deflector, downwind vane, or deflector that laterally redirects the movement of water through the deflector to generate a certain amount of lateral force. The deflector may be configured to redirect the flow of water through the deflector relative to the direction of movement of the deflector through the water. The deflector may include a steering device associated with the deflector. The steering device may redirect the flow of water to control the amount of lateral force generated by the deflector. The port deflector 170 may be connected to the starboard deflector 175 via a cable. The cable may include a streamer cable 195. For example, the port deflector 170 may be directly connected or coupled to the streamer cable 195. The port deflector 170 may be connected or coupled to the streamer cable 195 via a coupling device or a secondary cable. The coupling device may couple the port deflector 170 to the streamer cable 195. The streamer cable 195 may be connected to a plurality of streamers 115. The plurality of streamers 115 may be connected or coupled to the streamer cable 195 via a coupling device or secondary cable. The coupling device may couple the streamer cable 195 to the plurality of streamers 115. The plurality of streamers 115 may be coupled to the streamer cable 195 across substantially the entire length of the streamer cable 195.

[0053] The seabed target detection system 100 may include a starboard deflector 175. The starboard deflector 175 may be a deflector, downwind vane, or deflector that laterally redirects the movement of water through the deflector to generate a certain amount of lateral force. The deflector may be configured to redirect the flow of water through the deflector relative to the direction of movement of the deflector through the water. The deflector may include a steering device associated with the deflector. The steering device may redirect the flow of water to control the amount of lateral force generated by the deflector. The starboard deflector 175 may be connected to the port deflector 170 via a cable. The cable may include a streamer cable 195. For example, the starboard deflector 175 may be directly connected or coupled to the streamer cable 195. The starboard deflector 175 may be connected or coupled to the streamer cable 195 via a coupling device or a secondary cable. The coupling device may couple the starboard deflector 175 to the streamer cable 195. The streamer cable 195 may be connected to a plurality of streamers 115. The plurality of streamers 115 may be connected or coupled to the streamer cable 195 via a coupling device or secondary cable. The coupling device may couple the streamer cable 195 to the plurality of streamers 115. The plurality of streamers 115 may be coupled to the streamer cable 195 across substantially the entire length of the streamer cable 195.

[0054] Figure 7An example of a subsea target detection system 100 is shown. The subsea target detection system 100 may include a source array 127. The source array 127 may include a plurality of sources. The plurality of sources may include a central port source 150, a central starboard source 155, an auxiliary port source 160, and an auxiliary starboard source 165. A source in the plurality of sources may generate a source emission. A source in the plurality of sources may generate an acoustic wave. The source array 127 may generate an acoustic signal to be received by the receiver array 105. For example, the source array 127 may include a plurality of sources coupled to a source cable 197. The source array may include a pattern of sources. The source may include a central port source 150, a central starboard source 155, an auxiliary port source 160, and an auxiliary starboard source 165. For example, the central port source 150, the central starboard source 155, the auxiliary port source 160, and the auxiliary starboard source 165 may be coupled to a source cable 197 to form the source array 127. The source array 127 may include sixteen sources. For example, the plurality of sources may include one central port source 150 comprising two sources, one central starboard source 155 comprising two sources, three auxiliary port sources 160 comprising two sources each, and three auxiliary starboard sources 165 comprising two sources each.

[0055] Source array 127 may include at least one central source pair. Source array 127 may include a central source pair. The central source pair may include a central port source 150 and a central starboard source 155. The central source pair may be located between the central streamer pair. For example, central port source 150 may be located between central port streamer 125 and central starboard streamer 130. Central port source 150 may generate source emissions. Central port source 150 may generate acoustic waves. Central port source 150 may generate acoustic waves that will be reflected by a seafloor target and received by a plurality of receivers 110. Central port source 150 may generate acoustic waves that will be diffracted by a seafloor target and received by a plurality of receivers 110. Central starboard source 155 may be located between central port streamer 125 and central starboard streamer 130. Central starboard source 155 may generate source emissions. Central starboard source 155 may generate acoustic waves. Central starboard source 155 may generate acoustic waves that will be reflected by a seafloor target and received by a plurality of receivers 110. The central starboard source 155 may generate acoustic waves that will be diffracted by the seafloor target and received by the plurality of receivers 110. The central port source 150 may include a source pair. The central starboard source 155 may include a source pair.

[0056] The source array 127 may include at least one auxiliary port source 160. The source array may include an auxiliary port source 160. The auxiliary port source 160 may be located between the central port streamer 125 and the auxiliary port streamer 135. The auxiliary port source 160 may be located between the first auxiliary port streamer 135 and the second auxiliary port streamer 135. The auxiliary port source 160 may generate source emissions. The auxiliary port source 160 may generate acoustic waves. The auxiliary port source 160 may generate acoustic waves that will be reflected by a seabed target and received by a plurality of receivers 110. The auxiliary port source 160 may generate acoustic waves that will be diffracted by a seabed target and received by a plurality of receivers 110. The source array 127 may include a plurality of auxiliary port sources 160. For example, the source array 127 may include one, two, three, or more auxiliary port sources 160. The auxiliary port source 160 may include a source pair.

[0057] The source array 127 may include at least one auxiliary starboard source 165. The auxiliary starboard source 165 may be located between the central starboard streamer 130 and the auxiliary starboard streamer 140. The auxiliary starboard source 165 may be located between the first auxiliary starboard streamer 140 and the second auxiliary starboard streamer 140. The auxiliary starboard source 165 may generate source emissions. The auxiliary starboard source 165 may generate acoustic waves. The auxiliary starboard source 165 may generate acoustic waves that will be reflected by the seabed target and received by the plurality of receivers 110. The auxiliary starboard source 165 may generate acoustic waves that will be diffracted by the seabed target and received by the plurality of receivers 110. The source array 127 may include a plurality of auxiliary starboard sources 165. For example, the source array 127 may include one, two, three or more auxiliary starboard sources 165. The plurality of sources may include exactly eight sources. For example, the plurality of sources may include one central port source 150, one central starboard source 155, three auxiliary port sources 160, and three auxiliary starboard sources 165. The auxiliary starboard source 165 may include a source pair.

[0058] The seabed target detection system 100 may include a plurality of power streamers 190. The power cable 190 may include a cable for transmitting power. The power cable 190 may transmit power from the vessel 102 to a plurality of sources of the source array 127. The power cable 190 may transmit power from the vessel 102 to the central port source 150. The power cable 190 may transmit power from the vessel 102 to the central starboard source 155. The power cable 190 may transmit power from the vessel 102 to the auxiliary port source 160. The power cable 190 may transmit power from the vessel 102 to the auxiliary starboard source 165. The power cable 190 may transmit power from the vessel 102 to two sources in the central port source 150. The power cable 190 may transmit power from the vessel 102 to two sources in the central starboard source 155. The power cable 190 may transmit power from the vessel 102 to two sources in the auxiliary port source 160. Power cable 190 may transmit power from vessel 102 to two of auxiliary starboard sources 165 .

[0059] Figure 8 An example of a seabed object detection system 100 is shown. The seabed object detection system 100 may include a source array 127 and a receiver array 105. The seabed object detection system 100 may include two sources in the source array 127 disposed between receivers on two streamers in the plurality of streamers. The seabed object detection system 100 may include a plurality of sampling points 805. The sampling points 805 may be located on the seabed 220. The source array 127 and the receiver array 105 may be arranged in such a pattern that four samples are sampled at each sampling point 805.

[0060] Fig. 9 A method of detecting a subsea target according to an embodiment is illustrated. Briefly, method 900 may include providing a receiver array (block 905). Method 900 may include providing a source array (block 910). Method 900 may include generating an acoustic signal (block 915). Method 900 may include receiving diffraction data (block 920). Method 900 may include receiving reflection data (block 915).

[0061] The method 900 may include providing a receiver array (block 905). The method may include providing a receiver array comprising a plurality of receivers. The plurality of receivers may receive diffraction data diffracted from a target in the seafloor. The plurality of receivers may be disposed on a plurality of streamers. The plurality of streamers may include a central streamer pair. The central streamer pair may include a central port streamer and a central starboard streamer. The plurality of streamers may include at least one auxiliary port streamer at a first distance from the central streamer pair. The plurality of streamers may include at least one auxiliary starboard streamer located at a second distance from the central streamer pair opposite the at least one auxiliary port streamer.

[0062] Method 900 may include providing a source array (block 910). The source array may include a plurality of sources. The plurality of sources may generate source emissions. The plurality of sources may include at least one central source pair. The at least one central source pair may include a central port source and a central starboard source. The plurality of sources may be located between the central streamer pair. The source array may include at least one auxiliary port source. The at least one auxiliary port source may be located between the central port streamer and at least one auxiliary port streamer. The source array may include at least one auxiliary starboard source. The at least one auxiliary starboard source may be located between the central starboard streamer and at least one auxiliary starboard streamer.

[0063] In some embodiments, method 900 may include disposing at least one of the plurality of receivers outside a critical angle of reflection of at least one of the plurality of sources. The at least one receiver may receive diffraction data in response to the acoustic source. The critical angle may include a critical angle of reflection. The critical angle may include a critical angle of incidence. The critical angle of incidence is the angle at which a refracted wave propagates along an interface between two media. A receiver of the plurality of receivers may be disposed outside a critical angle of reflection of a source in a source array. A receiver of the plurality of receivers may be disposed outside a critical angle of reflection of a source in a plurality of sources in a source array. A receiver disposed outside a critical angle of reflection may receive diffraction data in response to the acoustic source. A receiver disposed outside a critical angle of reflection may receive diffraction data generated by a source emission. The source emission may generate an acoustic wave. A receiver disposed outside a critical angle of reflection may receive diffraction data generated by the acoustic wave.

[0064] Method 900 may include generating an acoustic signal (block 915). Method 900 may include generating an acoustic signal by a source array. The method may include generating an acoustic wave by a source array. The acoustic wave may be diffracted from a target in the seafloor. The source array may generate the acoustic wave. The acoustic wave may include source emission. The acoustic wave may be diffracted from a target in the seafloor. The receiver array may receive diffracted waves originating from the target in the seafloor. The central source pair may generate the acoustic wave. The central port source may generate the acoustic wave. The central starboard source may generate the acoustic wave. The auxiliary port source may generate the acoustic wave. The auxiliary starboard source may generate the acoustic wave. A receiver of a plurality of receivers in the receiver array may receive the diffracted wave. A receiver disposed on the central port streamer may receive the diffracted wave. A receiver disposed on the central starboard streamer may receive the diffracted wave. A receiver disposed on the auxiliary port streamer may receive the diffracted wave. A receiver disposed on the auxiliary starboard streamer may receive the diffracted wave.

[0065] In some embodiments, the method 900 may include towing the receiver array and the source array by a vessel. The method may include towing the receiver array 15 by a vessel to a position 15 to 50 meters above the seafloor. The method may include towing the source array by a vessel in front of the receiver array. The vessel may tow the receiver array and the source array so that the receiver array receives diffraction data diffracted from a target in the seafloor.

[0066] The method 900 may include receiving diffraction data (block 920). The method may include receiving, by a receiver array, diffraction data including diffraction waves originating from a seafloor target and emitted from a source. The method may include receiving, by a receiver array, diffraction data diffracted from a target in the seafloor. The method may include receiving, by a receiver array, diffraction waves originating from a target in the seafloor. A plurality of receivers in the receiver array may receive the diffraction data. The diffraction data may include diffraction waves diffracted from a seafloor target that is smaller than the Fresnel zone. The Fresnel zone is a reflection region from which most of the reflected energy is returned, and the arrival time of the reflection differs from the arrival time of the energy propagated from the energy source by less than half a cycle. Waves with such arrival times may constructively interfere and be detected by a single arrival. Therefore, it may be difficult to detect reflected waves from a target that is smaller than the Fresnel zone. However, a plurality of receivers 110 of the receiver array may detect diffraction waves from a target that is smaller than the Fresnel zone.

[0067] Method 900 may include receiving reflection data (block 915). The method may include receiving, by a receiver array, reflection data reflected from a target in the seafloor. A source array may generate source emissions. The source emissions may pass through a medium (e.g., seawater) and reflect from a seafloor target. The seafloor target may be completely buried in the seafloor. The seafloor target may be partially buried in the seafloor. The seafloor target may include a small shallow target such as a boulder. The width of a small shallow target may be between 10 cm and 100 cm (e.g., 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, 100 cm). The small shallow target may be greater than 100 cm. These small shallow targets may be less than 10 cm. The waves reflected from the seafloor target 220 may include reflection data. The reflection data may include reflection waves. A receiver array may receive reflection data. For example, a receiver array may receive reflection waves. A receiver in a plurality of receivers may receive reflection waves. The reflection data may include reflection waves originating from a seafloor target. The reflection data may include reflection waves generated from the source emission. A plurality of sources in the source array may generate acoustic signals. A plurality of receivers in the receiver array may receive reflection data reflected from a target in the seafloor. The reflection data may include reflected waves. A receiver in the plurality of receivers may receive reflected waves reflected from a target in the seafloor and generated by a source in the plurality of sources in the source array.

[0068] The subject matter and operation embodiments described in this specification may be implemented in digital electronic circuits or in computer software, firmware or hardware, including the structures disclosed in this specification and their structural equivalents, or a combination of one or more of them. The subject matter described in this specification may be implemented as one or more computer programs (e.g., one or more circuits of computer program instructions), which are encoded on one or more computer storage media for execution by a data processing device or for controlling the operation of a data processing device. Alternatively or in addition, program instructions may be encoded on artificially generated propagation signals, such as electrical, optical or electromagnetic signals generated by a machine, which are generated to encode information for transmission to a suitable receiver device for execution by a data processing device. Computer storage media may be or be included in a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination of one or more of them. In addition, although a computer storage medium is not a propagation signal, a computer storage medium may be a source or destination of computer program instructions encoded in an artificially generated propagation signal. A computer storage medium may also be or be included in one or more separate components or media (e.g., multiple CDs, disks or other storage devices).

[0069] The operations described in this specification may be performed by a data processing device on data stored on one or more computer-readable storage devices or received from other sources. The term "data processing device" or "computing device" includes various devices, equipment and machines for processing data, including, for example, a programmable processor, a computer, a system on a chip, or a plurality of the foregoing or a combination thereof. The device may include a dedicated logic circuit, such as an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). In addition to hardware, the device may also include code that creates an execution environment for the computer program in question, for example, code that constitutes processor firmware, a protocol stack, a database management system, an operating system, a cross-platform runtime environment, a virtual machine, or a combination of one or more thereof. The device and the execution environment may implement a variety of different computing model infrastructures, such as web services, distributed computing, and grid computing infrastructures.

[0070] A computer program (also referred to as a program, software, software application, script, or code) may be written in any form of programming language, including compiled or interpreted languages, declarative or procedural languages, and may be deployed in any form, including as a stand-alone program or as a circuit, component, subroutine, object, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program may be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files storing one or more circuits, subroutines, or portions of code). A computer program may be deployed to execute on one computer or on multiple computers located at one site or distributed over multiple sites and interconnected by a communications network.

[0071] Processors suitable for executing computer programs include, for example, any one or more processors of a microprocessor and a digital computer. The processor may receive instructions and data from a read-only memory or a random access memory or both. The elements of a computer are a processor for performing actions according to instructions and one or more memory devices for storing instructions and data. The computer includes or is operably connected to receive data from or transmit data to or to one or more large-capacity storage devices (such as magnetic disks, magneto-optical disks, or optical disks) for storing data. The computer does not need to have such a device. In addition, the computer may be built into another device, such as a personal digital assistant (PDA), a global positioning system (GPS) receiver, or a portable storage device (such as a universal serial bus (USB) flash drive), to name a few. Devices suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, for example, semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD ROM and DVD-ROM disks. The processor and memory may be supplemented by or incorporated into a dedicated logic circuit.

[0072] To provide interaction with a user, embodiments of the subject matter described in this specification may be implemented on a computer having a display device, such as a CRT (cathode ray tube) or LCD (liquid crystal display) monitor for displaying information to the user, a keyboard, and a pointing device such as a mouse or trackball, through which the user can provide input to the computer. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback, such as visual feedback, auditory feedback, or tactile feedback; and any form of input from the user including acoustic, voice, or tactile input may be received.

[0073] The embodiments described herein can be implemented in any of a variety of ways, including, for example, using hardware, software, or a combination thereof. When implemented in software, the software code can be executed on any suitable processor or processor collection, whether provided in a single computer or distributed among multiple computers.

[0074] Likewise, a computer may have one or more input and output devices. Among other things, these devices may be used to present a user interface. Examples of output devices that may be used to provide a user interface include a printer or display screen for visual presentation of the output and a speaker or other sound generating device for auditory presentation of the output. Examples of input devices that may be used for a user interface include a keyboard and a pointing device, such as a mouse, a touch pad, and a digitized tablet computer. As another example, a computer may receive input information through speech recognition or other auditory formats.

[0075] These computers can be interconnected in any suitable form through one or more networks, including local area networks or wide area networks (such as enterprise networks) and intelligent networks (IN) or the Internet. Such networks can be based on any suitable technology and can operate according to any suitable protocol, and can include wireless networks, wired networks or fiber optic networks.

[0076] A computer for implementing at least a portion of the functions described herein may include a memory, one or more processing units (also referred to herein as "processors"), one or more communication interfaces, one or more display units, and one or more user input devices. The memory may include any computer-readable medium, and may store computer instructions (also referred to herein as "processor executable instructions") for implementing the various functions described herein. The processing unit may be used to execute instructions. The communication interface may be connected to a wired or wireless network, a bus, or other communication device, and thus allow the computer to send communications to or receive communications from other devices. For example, a display unit may be provided to allow a user to view various information related to the execution of instructions. For example, a user input device may be provided to allow a user to make manual adjustments, make selections, enter data or various other information during the execution of instructions, or interact with the processor in any of a variety of ways.

[0077] The various methods or processes outlined herein may be encoded as software that can be executed on one or more processors using any of a variety of operating systems or platforms. In addition, such software may be written using any of a number of suitable programming languages ​​or programming or scripting tools, and may also be compiled into executable machine language code or intermediate code that is executed on a framework or virtual machine.

[0078] In this regard, various inventive concepts may be embodied as a computer-readable storage medium (or multiple computer-readable storage media) (e.g., computer memory, one or more floppy disks, optical disks, optical disks, tapes, flash memory, circuit configurations in field programmable gate arrays or other semiconductor devices or other non-transitory media or tangible computer storage media), which is encoded with one or more programs that, when executed on one or more computers or other processors, perform methods of implementing various embodiments of the solution discussed above. The computer-readable medium or multiple computer-readable media may be removable so that the one or more programs stored thereon can be loaded onto one or more different computers or other processors to implement various aspects of the present solution as discussed above.

[0079] In this document, the term "program" or "software" is used to refer to any type of computer code or computer executable instruction set that can be used to program a computer or other processor to implement various aspects of the above-described embodiments. The one or more computer programs that perform the methods of the present solution when executed need not reside on a single computer or processor, but can be distributed in a modular manner among multiple different computers or processors to implement various aspects of the present solution.

[0080] Computer executable instructions may be in various forms, such as program modules, executed by one or more computers or other devices. Program modules may include routines, programs, objects, components, data structures, or other components that perform specific tasks or implement specific abstract data types. In various embodiments, the functionality of program modules may be combined or distributed as desired.

[0081] Likewise, data structures may be stored in a computer-readable medium in any suitable form. To simplify the description, data structures are shown as having fields that are associated by location in the data structure. Such relationships may also be achieved by allocating storage space for the fields, which have location information in the computer-readable medium that conveys the relationship between the fields. However, any suitable mechanism may be used to establish the relationship between the information in the fields of the data structure, including by using pointers, tags, or other mechanisms that establish relationships between data elements.

[0082] Any reference to an embodiment or element or action of a system and method mentioned in the singular herein may include an embodiment comprising a plurality of these elements, and any reference to a plural form of any embodiment or element or action herein may include an embodiment comprising only a single element. References in the singular or plural form are not intended to limit the currently disclosed system or method, their parts, actions or elements to a single or multiple configurations. References to any action or element based on any information, action or element may include an embodiment in which the action or element is based at least in part on any information, action or element.

[0083] Any embodiment disclosed herein may be combined with any other embodiment, and references to "an embodiment," "some embodiments," "alternative embodiments," "various embodiments," "one embodiment," etc. are not necessarily mutually exclusive and are intended to indicate that a particular feature, structure, or characteristic described in conjunction with an embodiment may be included in at least one embodiment. These terms as used herein do not necessarily all refer to the same embodiment. Any embodiment may include or be exclusively combined with any other embodiment in any manner consistent with the aspects and embodiments disclosed herein.

[0084] References to "or" may be interpreted as inclusive, such that any term described using "or" may indicate any of a single, more than one, and all of the described terms. References to at least one of a joint list of terms may be interpreted as inclusive OR to indicate any of a single, more than one, and all of the described terms. References to "at least one of 'A' and 'B'" may include only "A," only "B," and both "'A' and 'B'." Elements other than "A" and "B" may also be included.

[0085] The systems and methods described herein may be embodied in other specific forms without departing from their characteristics.The foregoing embodiments are illustrative rather than limiting of the described systems and methods.

[0086] Where a technical feature in the drawings, detailed description or any claim is followed by a reference numeral, the reference numeral is included to increase the intelligibility of the drawings, detailed description and claims. Therefore, neither the reference numerals nor their absence will have any limiting effect on the scope of any claim element.

[0087] The systems and methods described herein may be embodied in other specific forms without departing from their characteristics. The foregoing embodiments are illustrative rather than limiting of the systems and methods described. Therefore, the scope of the systems and methods described herein is indicated by the appended claims rather than the preceding description, and changes within the meaning and scope of equivalents of the claims are included therein.

Claims

1. A seabed target detection system (100), comprising: A receiver array (105) comprising a plurality of receivers (110) receiving diffraction data diffracted from a target in the seafloor and arranged on a plurality of streamers (115), the plurality of streamers (115) comprising: a central streamer pair, comprising a central port streamer (125) and a central starboard streamer (130); at least one auxiliary port streamer (135) positioned a first distance from the central pair of streamers; and at least one auxiliary starboard streamer (140) positioned opposite the at least one auxiliary port streamer (135) and a second distance from the central streamer pair; A source array (127) comprising a plurality of sources for generating source emissions (215) and comprising: at least one central source pair, the at least one central source pair comprising a central port source (150) and a central starboard source (155) and located between the central streamer pair; at least one auxiliary port source (160), the at least one auxiliary port source (160) being located between the central port streamer (125) and the at least one auxiliary port streamer (135); at least one auxiliary starboard source (165), the at least one auxiliary starboard source (165) being located between the central starboard streamer (130) and the at least one auxiliary starboard streamer (140); and At least one of the plurality of receivers (110) is disposed outside a critical reflection angle of at least one of the plurality of sources, and receives diffraction data in response to the sound source.

2. The seabed target detection system (100) according to claim 1, comprising: The receiver array (105) is used to receive diffraction data including diffraction waves (205) originating from a seabed target (210) and generated from a source emission (215).

3. The seabed target detection system (100) according to claim 1, comprising: Port side deflector (170); as well as A starboard deflector (175) is connected to the port deflector (170) by a cable connected to the plurality of streamers (115).

4. The seabed target detection system (100) according to claim 1, comprising: Ships (102); a port deflector (170), the port deflector (170) being connected to the vessel (102) by a port cable; a starboard deflector (175), the starboard deflector (175) being connected to the vessel (102) by a starboard cable (185); a streamer cable connecting the port deflector (170) to the starboard deflector (175); and A source cable connects the port cable (180) to the starboard cable (185), and the source cable is connected to the source array (127).

5. The seafloor target detection system (100) of claim 1, comprising a vessel (102) configured to tow the receiver array (105) and the source array (127).

6. The seabed target detection system (100) according to claim 1 comprises a vessel (102) configured to tow the receiver array and the source array (127), the source array (127) being used to generate acoustic signals, and the plurality of receivers (110) in the receiver array (105) being used to receive diffraction data diffracted from targets in the seabed.

7. The seafloor object detection system (100) of claim 1, wherein the plurality of streamers (115) comprises exactly eight streamers and the plurality of sources comprises exactly eight sources.

8. The seabed target detection system (100) according to claim 1, comprising: The plurality of receivers (110) are used to receive diffraction data diffracted from the target smaller than the Fresnel zone.

9. The seabed target detection system (100) according to claim 1, comprising: The receiver array (105) is disposed 15 to 50 meters above the sea floor.

10. The seabed target detection system (100) according to claim 1, comprising: The at least one auxiliary port source (160) is located between the central port streamer (125) and a centerline of the central port streamer (125) and the at least one auxiliary port streamer (135); and The at least one auxiliary starboard source (165) is located between the central starboard streamer (130) and a centerline of the central starboard streamer (130) and the at least one auxiliary starboard streamer (140).

11. The seabed target detection system (100) according to claim 1, comprising the plurality of sources for generating acoustic signals, and the plurality of receivers (110) in the receiver array (105) for receiving reflection data reflected from targets in the seabed.

12. The seabed target detection system (100) according to claim 1, comprising: The source array (127) is used to generate acoustic waves that diffract from a target in the seafloor; and The receiver array (105) is used to receive diffracted waves originating from a target in the seafloor.

13. A method (900) for detecting a seabed target, comprising: A receiver array is provided (905) comprising a plurality of receivers that receive diffraction data diffracted from a target in the seafloor and the plurality of receivers are disposed on a plurality of streamers, the plurality of streamers comprising: a center towline pair, including a center port towline and a center starboard towline; at least one auxiliary port streamer positioned a first distance from the central pair of streamers; and at least one auxiliary starboard streamer positioned opposite the at least one auxiliary port streamer and a second distance from the central pair of streamers; Providing (910) a source array comprising a plurality of sources for generating source emissions and comprising: at least one central source pair, the at least one central source pair comprising a central port source and a central starboard source and located between the central streamer pair; at least one auxiliary port source, the at least one auxiliary port source located between the central port streamer and the at least one auxiliary port streamer; at least one auxiliary starboard source, the at least one auxiliary starboard source located between the central starboard streamer and the at least one auxiliary starboard streamer; and At least one of the plurality of receivers is disposed outside a critical angle of reflection of at least one of the plurality of sources, the at least one receiver receiving diffraction data in response to the acoustic source.

14. The method (900) of claim 13, comprising: Diffraction data including diffraction waves originating from a seafloor target and emitted from a source is received by the receiver array.

15. The method (900) of claim 13, comprising: towing the receiver array and the source array by a vessel; generating (915) an acoustic signal from the source array; as well as Diffraction data diffracted from a target in the seafloor is received (920) by the receiver array.

16. The method according to claim 13, comprising: generating (915) an acoustic signal from the source array; as well as Reflection data reflected from a target in the seafloor is received (925) by the receiver array.

17. The method according to claim 13, comprising: generating acoustic waves from the source array, the acoustic waves being adapted to diffract from a target in the seafloor; as well as Diffracted waves originating from a target in the seafloor are received by the receiver array.

18. The method according to claim 13, comprising: The receiver array is towed by a vessel to a position 15 to 50 meters above the sea floor.

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