Underwater direction signal processing system

Claim 2

A direction-finding system for ascertaining the bearings of sources of incident acoustical signals in water, said system having a plurality of transducers for converting said acoustical signals into at least a first and second electrical signals with said electrical signals comprising a plurality of frequency components, said transducers each generating an electrical signal that varies as a function of the angle between a sensitive axis of said transducer and the direction of the incoming acoustical signals with the sensitive axis of said transducers being oriented at a predetermined angle with respect to each other and to a known geographical reference; wherein the improvement comprises: a. frequency separating means adapted to receive first and second electrical signals, said frequency separating means arranged for separating each of said first and second electrical signals according to the frequency components thereof and to select a discrete frequency component in each of said electrical signals for processing; b. means for converting said selected frequency component of said first and second electrical signals to first and second amplitude related signals, the ratio of said first and second amplitude related signals corresponding to the tan of the bearing of said acoustical signal and the relative polarity of said first and second amplitude related signals being indicative of the quadrant containing the incident acoustical signal as measured from said known geographical reference, and c. bearing computation means, said computation means being responsive to the polarity and amplitude of said first and second amplitude related signals and arranged to provide an output signal representative of the direction of the source of said incident acoustical signal.

Claim 3

A direction-finding system for ascertaining the bearings of sources of incident acoustical signals in water, said system having a plurality of transducers for converting said acoustical signals into at least a first and second electrical signals with said electrical signals comprising a plurality of frequency components, said transducers each generating an electrical signal that varies as a function of the angle between a sensitive axis of said transducer and the direction of the incoming acoustical signals with the sensitive axis of said transducers being oriented at a predetermined angle with respect to each other and to a known geographical reference; wherein the improvement comprises: a. frequency separating means adapted to receive first and second electrical signals, said frequency separating means arranged for separating each of said first and second electrical signals according to the frequency components thereof and to select a discrete frequency component in each of said electrical signals for processing; b. means for converting said selected frequency component of said first and second electrical signals to first and second amplitude related signals, the ratio of said first and second amplitude related signals corresponding to the tan of the bearing of said acoustical signal and the relative polarity of said first and second amplitude related signals being indicative of the quadrant containing the incident acoustical signal as measured from said known geographical reference, and c. bearing computation means, said computation means being responsive to the polarity and amplitude of said first and second amplitude related signals and arranged to provide an output signal representative of the direction of the source of said incident acoustical signal.

Claim 4

A direction-finding system for ascertaining the bearings of sources of incident acoustical signals in water, said system having a plurality of transducers for converting said acoustical signals into at least a first and second electrical signals with said electrical signals comprising a plurality of frequency components, said transducers each generating an electrical signal that varies as a function of the angle between a sensitive axis of said transducer and the direction of the incoming acoustical signals with the sensitive axis of said transducers being oriented at a predetermined angle with respect to each other and to a known geographical reference; wherein the improvement comprises: a. frequency separating means adapted to receive first and second electrical signals, said frequency separating means arranged for separating each of said first and second electrical signals according to the frequency components thereof and to select a discrete frequency component in each of said electrical signals for processing; b. means for converting said selected frequency component of said first and second electrical signals to first and second amplitude related signals, the ratio of said first and second amplitude related signals corresponding to the tan of the bearing of said acoustical signal and the relative polarity of said first and second amplitude related signals being indicative of the quadrant containing the incident acoustical signal as measured from said known geographical reference, and c. bearing computation means, said computation means being responsive to the polarity and amplitude of said first and second amplitude related signals and arranged to provide an output signal representative of the direction of the source of said incident acoustical signal.

Claim 5

A direction-finding system described in claim 1, wherein said frequency separating means comprises: a first reference signal having a first frequency, first means to combine said first reference signal with said first and second electrical signals, to produce a third and fourth electrical signals having a frequency being greater than said first frequency and the frequency components of said first and second electrical signals, a second reference signal having a second frequency, said second frequency being less than the frequency of the combined signals, second means to combine said third and fourth electrical signals with said second reference signal, said second means being arranged to convert each of said third and fourth electrical signals combined with said second reference signal to a first and second pair of phase related electrical signals with each having frequency components greater than and less than said second frequency, said phases of said pair of electrical signals being arranged to cancel those electrical signals having a frequency on one side of said frequency and combine those electrical signals having a frequency on the opposite side of second frequency, and a third means to combine said first and second pair of phase related electrical signals producing said selected frequency component of said first and second electrical signals for processing.

Claim 6

A direction-finding system described in claim 2 wherein said second means includes a phase shifting network whereby one of said pair in each of said first and second pair of phase related signals is further shifted in phase by a predetermined angle, and summing means arranged to combine each of said first and second pair of phase related signals for producing said discrete frequency component signal in each of said first and second electrical signals for processing.

Claim 7

A direction-finding system described in claim 1 further including an omni-directional transducer providing an output electrical signal whose phase is independent on the bearing of said acoustical signal; and said bearing computation means arranged to compare the phase of each of said discrete frequency component signals with the phase of the output signal of said omni-directional transducer and producing a resultant signal for each of the compared signals having a first polarity if the compared signals are in phase and a second polarity if the compared signals are out of phase with the polarity of each of said resultant signals being indicative of the quadrant of said incident acoustical signal.

Claim 8

A direction-finding system described in claim 4 wherein said bearing computation means further includes: an integrator unit, said integrator unit being arranged to convert each of said resultant discrete frequency component signals to a pair of amplitude related signals whose amplitude ratio corresponds to the tan of the bearing of said incident acoustical signal.

Claim 9

A direction-finding system described in claim 1 wherein said bearing computation means includes: a reference signal source arranged to provide a first and second reference signals having the same frequency and related in phase by a predetermined angle, and means to combine one of said amplitude related signals with said first reference signal and the other of said amplitude related signals with the other of said reference signals, said means being arranged to sum each of the combined signals to provide a resultant signal having a frequency of said refernece signal and a phase angle essentially equal to the direction of said incident acoustical signal, second means arranged to combine said resultant signal with one of said first reference signals to produce a second combined signal having a constant amplitude and repetition rate and a pulse width which is relateed to the direction of said incident acoustical signal, third means adapted to convert the pulse width of said second combined signal to said output signal having an amplitude related to the direction of said incident acoustical signal, and display means responsive to said output signal and to provide a visual display of the direction of the source of said incident acoustical signal.

Claim 10

A direction-finding system for ascertaining the bearings of the sources of underwater acoustical signals, said system comprising a. a pair of bidirectional transducers, each of which has a response to incoming acoustical signals that is a cosine function of the bearing of the source of said acoustical signal relative to the sensitive axis of the transducer, and the sensitive axis of said transducer being arranged substantially perpendicular to each other, b. an omni-directional transducer having a response which is independent of the bearing of said acoustical signal, c. a reference signal source, d. means for modulating quadrature related signals from said reference source with the respective outputs of said bidirectional transducers and summing the modulated signals to provide a resultant signal whose phase angle relative to the phase of the signal of said reference source is substantially equal to the bearing of the source of said acoustical signal relative to the sensitive axis of one of said bidirectional transducers, e. a transmitter connected to effect a wireless transmission of the modulated signal and the output of said omni-directional transducer, f. a receiver arranged to receive the signals from said transmitter, said receiver including means for demodulating said resultant signal and providing a pair of amplitude related signals whose ratio is essentially equal to the tan of the bearing of said acoustical signal and for providing a signal equivalent to the response of said omni-directional transducer, g. signal translator means arranged for separating said amplitude related signals and said omni-directional signal according to the frequency components thereof and selecting one discrete frequency component present in each of said amplitudE related signals and said omni-directional signal for processing and the amplitude ratio of the discrete frequency component of said amplitude related signals being equal to the bearing of said acoustical signal, h. means for comparing said discrete frequency component of said omni-directional signal with each of said discrete frequency component signals of said amplitude related signals and producing a first pair of amplitude related signals whose ratio is relative to the tangent of the bearing of the acoustical signals, and i. bearing computer means, said bearing computer means converting said pair of amplitude related signals to an output signal having a constant amplitude and fixed repetition rate and a pulse width which is proportional to the bearing of the source of said acoustical signal.

Claim 11

A direction-finding system for ascertaining the bearings of the sources of underwater acoustical signals, said system comprising a. a pair of bidirectional transducers, each of which has a response to incoming acoustical signals that is a cosine function of the bearing of the source of said acoustical signal relative to the sensitive axis of the transducer, and the sensitive axis of said transducer being arranged substantially perpendicular to each other, b. an omni-directional transducer having a response which is independent of the bearing of said acoustical signal, c. a reference signal source, d. means for modulating quadrature related signals from said reference source with the respective outputs of said bidirectional transducers and summing the modulated signals to provide a resultant signal whose phase angle relative to the phase of the signal of said reference source is substantially equal to the bearing of the source of said acoustical signal relative to the sensitive axis of one of said bidirectional transducers, e. a transmitter connected to effect a wireless transmission of the modulated signal and the output of said omni-directional transducer, f. a receiver arranged to receive the signals from said transmitter, said receiver including means for demodulating said resultant signal and providing a pair of amplitude related signals whose ratio is essentially equal to the tan of the bearing of said acoustical signal and for providing a signal equivalent to the response of said omni-directional transducer, g. signal translator means arranged for separating said amplitude related signals and said omni-directional signal according to the frequency components thereof and selecting one discrete frequency component present in each of said amplitudE related signals and said omni-directional signal for processing and the amplitude ratio of the discrete frequency component of said amplitude related signals being equal to the bearing of said acoustical signal, h. means for comparing said discrete frequency component of said omni-directional signal with each of said discrete frequency component signals of said amplitude related signals and producing a first pair of amplitude related signals whose ratio is relative to the tangent of the bearing of the acoustical signals, and i. bearing computer means, said bearing computer means converting said pair of amplitude related signals to an output signal having a constant amplitude and fixed repetition rate and a pulse width which is proportional to the bearing of the source of said acoustical signal.

Claim 12

The system defined in claim 7 in which said signal translator means includes: a first reference signal having a first frequency, means to combine said first reference signal with each of said amplitude related signals and said omni-directional signal to produce a first, second and third resultant signals having a frequency greater than said first frequency, a second refernece signal having a second frequency, second means to combine said first, second and third resultant signals with said second reference signal, said second means being arranged to convert each of said first, second and third resultant signals combined with said second reference signals to a first, second and third pair of phase related signals with each having frequency components greater than and less than said second frequency, the phases of said pair of phase related signals being arranged to cancel those electrical signals having a frequency on one side of said second frequency and add those electrical signals having a frequency on the opposite side of second frequency, and means to sum each of said first, second and third pair of phase related signals producing a pair of amplitude related signals and said omni-directional signal at said discrete frequency component for processing.

Claim 13

The system defined in claim 8 wherein said second means including a phase shifting network whereby one of said phase related signals is further shifted in phase by a predetermined angle.

Claim 14

The system defined in claim 8 wherein the means for comparing the discrete frequency component of said omni-directional signal with each of said amplitude related signals having said discrete frequency component includes: a. a pair of phase detectors, each being arranged to receive said omni-directional signal and one of said pair of amplitude related signals at said discrete frequency component and adapted to provide a first output signal having a first polarity if the compared signals are in phase and a second output signal having a second polarity if the compared signals are out of phase, and b. a pair of integrators, each of said integrators arranged to receive one of said first or second output signals of one of said phase detectors, said integrators providing a first pair of amplitude-related signals whose amplitude ratio is essentially the tangent of the bearing of the source of said acoustical signal.

Claim 15

The systemm defined in claim 8 wherein said bearing computer means includes a. a third reference signal source having a third frequency and arranged to provide a pair of reference signals having the same frequency and related in phase by a predetermined angle, b. third means to combine one of said first pair of amplitude related signals with one of said third reference signals and the other of said amplitude related signals with the other of said third reference signals to produce a first and second combined signals, and c. fourth means to add said first and second combined signals to produce a combination signal having the frequency of said third reference signal and a phase which is shifted from the phase of one of said third reference signals by an angle essentially equal To said bearing of the source of said acoustical signal.

Claim 16

The system defined in claim 11 wherein said bearing computer means includes: a. fifth means to combine said combination signal with one of said third reference signals to produce a second combination signal having a constant amplitude and repetition rate and a pulse width which is proportional to said bearing, and b. sixth means to convert said second combination signal to said output signal whose amplitude is equal to said bearing.

Claim 17

The system defined in claim 12 further including display means arranged to receive said output signal for processing and to provide a visual display of the direction of the source of said acoustical signal.