Suppressed feature waveform for modulated sonar transmission
US7596054B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 3, 2005 |
| Grant date | Sep 29, 2009 |
| Priority date | — |
| Expiry date | Apr 5, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2201/70715
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A suppressed feature waveform sonar transmission is produced by modulating a carrier wave with a baseband waveform that is generated from a known pulse sequence. A waveform embodiment of the pulse sequence is modified to create interference among the primary lobes of the constituent waveforms that are representative of the individual pulses. The baseband waveform so created appears as noise, making the baseband waveform modulation of the sonar transmission difficult to detect without knowledge of the pulse sequence or baseband waveform structure. The sonar transmission can be analyzed by cross-correlating the received signal with the baseband waveform or the pulse sequence waveform. The pulse sequence is preferably a complementary sequence. Modification of the pulse sequence may be obtained by passing an embodiment of the pulse sequence through a bandpass filter. In such a modification, the bandpass filter is preferably overdriven by a pulse sequence waveform having a frequency that is about eight to about ten times the bandwidth of the filter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.