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DE-102025003154-B3 - Methods for assessing sonar reflections

DE102025003154B3DE 102025003154 B3DE102025003154 B3DE 102025003154B3DE-102025003154-B3

Abstract

A procedure for assessing sonar reflections (22) is disclosed comprising the following steps: a) Emitting a sonar signal (24) wherein the sonar signal (24) has a gap (28) in the time domain or in the frequency domain; b) Receiving reflections (22a, 22b) of the sonar signal (24); c) Evaluate the reflections (22a, 22b) of the sonar signal in the gap (28) to assess the reflections (22a, 22b).

Inventors

  • Tobias Fassbender
  • Patricio Muñoz-Esparza

Assignees

  • THYSSENKRUPP AG
  • TKMS ATLAS ELEKTRONIK GMBH

Dates

Publication Date
20260513
Application Date
20250603

Claims (10)

  1. Method for evaluating sonar reflections (22) comprising the following steps: a) Emitting a sonar signal (24) wherein the sonar signal (24) has a gap (28) in the time domain or in the frequency domain; b) Receiving reflections (22a, 22b) of the sonar signal (24); c) Evaluating the reflections (22a, 22b) of the sonar signal in the gap (28) to evaluate the reflections (22a, 22b).
  2. Procedure according to Claim 1 , where the assessment of the reflections (22a, 22b) includes the distinction between actual reflections (22a) and artificially generated reflections (22b).
  3. Method according to one of the preceding claims, wherein the assessment of the reflections (22a, 22b) includes a comparison of the reflection (22a, 22b) in the gap (28) and the background noise (30).
  4. Method according to one of the preceding claims, wherein the evaluation of the reflections (22a, 22b) comprises a detection of a level increase relative to the background noise (30).
  5. Signal processing unit (20) for evaluating sonar reflections (22) with the following features: - a sonar signal processing unit (32) configured to process received reflections (22a, 22b) of a sonar signal (24), wherein the emitted sonar signal (24) has a gap (28) in the time domain or in the frequency domain and evaluates the reflections (22a, 22b) of the sonar signal (24) in the gap (28) in order to evaluate the reflections (22a, 22b).
  6. Signal processing unit (20) according to Claim 5 , with a sonar signal generator (34) configured to control an underwater sound transducer such that the underwater sound transducer emits the sonar signal (24).
  7. Torpedo comprising the signal processing unit (20) according to one of the Claims 5 or 6 or wherein the torpedo performs the procedure according to one of the Claims 1 until 4 executes.
  8. Maritime target monitoring system comprising an underwater vehicle and a launching platform, in particular a watercraft, for the underwater vehicle, wherein the maritime target monitoring system includes the signal processing unit (20) according to one of the Claims 5 or 6 exhibits or the procedure according to one of the Claims 1 until 4 executes.
  9. Maritime target monitoring system according to Claim 8 , where the underwater vehicle is a torpedo.
  10. A computer program comprising instructions that, when executed by a computer, cause it to: - process received reflections (22a, 22b) of a transmitted sonar signal (24), wherein the transmitted sonar signal (24) has a gap (28) in the time domain or frequency domain; - evaluate the reflections (22a, 22b) of the sonar signal (24) in the gap (28) in order to assess the reflections (22a, 22b).

Description

The invention relates to the detection of irregularities using active sonar. Active sonar describes the detection of objects based on the reflection of a known, emitted sonar pulse. This includes not only classic active sonar (the same platform transmits and receives) but also bi-static (one platform transmits, a second receives) and multi-static (multiple platforms transmit, another receives). Currently, however, there are increasing efforts to manipulate the reflection of the sonar signal by means of emitted sound waves. This allows the reflection to be artificially created, thus masking the object's true signature. In particular, a torpedo approaching a target can be deceived, causing it to miss its target or attack the wrong one. Such a decoy device can then, for example, attack the decoy instead of its intended target. DE 10 2012 110 943 A1 reveals an underwater signal sequence with at least two acoustic sub-signals, each sub-signal being assigned a transmission time index and an expectation time index. US 5 062 083 A reveals a sonar target simulator. The object of the present invention is therefore to create an improved concept for the detection of irregularities in reflected sonar pulses. The problem is solved by the subject matter of the independent patent claims. Further advantageous embodiments are the subject matter of the dependent patent claims. Exemplary embodiments show a method for evaluating sonar reflections comprising the following steps a), b), and c). In step a), a sonar signal is emitted from any platform, in particular a watercraft, and/or an oil rig and/or the base of a wind turbine and/or a harbor wall. The sonar signal is emitted, in particular, by means of an underwater sound transmitter or an array of underwater sound transmitters (i.e., underwater transducers used to transmit underwater sound). The sonar signal exhibits a gap in either the time or frequency domain. That is, in the time domain, there is a pause during the emission of the sonar signal. In the frequency domain, a portion of the frequency spectrum covered by the sonar signal is omitted. In step b), reflections of the sonar signal are received, in particular by an underwater sound receiver. The underwater sound receiver can be located on the same platform as the underwater sound transmitter, or on a different platform. In step c), the reflections of the sonar signal in the gap are evaluated to assess them. Preferably, classical sonar signal processing takes place first. At an arbitrary point in time, but especially after the usual sonar signal processing, the signal component of the reflection of the sonar signal in the gap is evaluated. Since the object, which is unaware of the emitted signal pulse, also performs sonar signal processing before it can emit its own sonar signal to manipulate the reflection, the background noise present in the gap is inevitably also subjected to sonar signal processing. This sonar signal processing of the background noise reveals that the reflection is a distorted reflection. In other words, the assessment of the reflections involves distinguishing between actual reflections and artificially generated reflections. One idea is therefore to create a signal-free area in the transmitted sonar signal, which can be used to assess whether the received reflection of the sonar signal has been subjected to sonar signal processing and the actual reflection has thus been manipulated, i.e., the received reflection has been artificially generated. In exemplary implementations, evaluating the reflections involves comparing the reflection in the gap with the background noise. For example, evaluating the reflections includes detecting a level increase compared to the background noise. If the received sonar signal in the gap behaves differently than the background noise, it can be assumed that the reflection in the received sonar signal was artificially generated, i.e., did not arise solely due to physical laws. Furthermore, a signal processing unit for evaluating sonar reflections is disclosed, comprising a sonar signal processing unit configured to process received reflections of a sonar signal, wherein the emitted sonar signal has a gap in the time domain or frequency domain, and to evaluate the reflections of the sonar signal in the gap in order to determine the reflection to assess. Optionally, the signal processing unit includes a sonar signal generator configured to control an underwater transducer such that the transducer emits the sonar signal. The signal processing unit is advantageously a computer, wherein the sonar signal processing unit and optionally the sonar signal generator are implemented in software. Furthermore, a torpedo is disclosed comprising the aforementioned signal processing unit or wherein the torpedo performs the aforementioned method. Furthermore, a maritime target monitoring system, in particular a target destruction system, is disclosed. The target monitoring system compr