Submarine detection system

In a system for detecting the location of an object submerged in a medium having transmission characteristics substantially different from that of the atmosphere by means of radiated electromagnetic energy containing a multiplicity of frequencies;

• means to receive an incident radiation of said electromagnetic energy propagated in a first electric field and the reflection of said radiation propagated in a different electric field caused by the presence of a submerged object within the range of said system, said reflection containing some of the frequencies of said incident radiation, means to derive from said received incident radiation and said reflected radiation frequencies common to both, and means to compare said radiations of common frequencies to determine the relative field strength thereof, and thereby obtain a measure corresponding substantially to the range of the submerged object.

In a system for detecting the location of an object submerged in a medium having transmission characteristics substantially different from that of the atmosphere by means of radiated electromagnetic energy containing a multiplicity of frequencies and regardless of the source of said energy propagated in a first electric field;

• means to receive an incident radiation propagated in a different electric field of said electromagnetic energy and the reflection of said radiation caused by the presence of a submerged object within the range of said system, said reflection containing some of the frequencies of said incident radiation, means to filter from said received incident radiation and said reflected radiation all frequencies outside of a given range of frequencies and means to compare the field strength of said filtered reflected radiation with the field strength of said incident radiation to determine the relation therebetween, and thereby obtain a measure corresponding substantially to the range of the submerged object.

In a system for detecting the location of an object submerged in a medium having transmission characteristics substantially different from that of the atmosphere by means of radiated electromagnetic energy containing a multiplicity of frequencies and regardless of the source of said energy;

• means to receive an incident radiation of said electromagnetic energy and the reflection of said radiation caused by the presence of a submerged object within the range of said system, said reflection containing some of the frequencies of said incident radiation, means to filter from the said received incident radiation and said reflected radiation all frequencies outside of a given frequency, means to delay said filtered incident radiation and means to compare the field strength of said delayed incident radiation with the field strength of said filtered reflected radiation to determine the relation therebetween, and thereby obtain a measure corresponding substantially to the range of the submerged object.

In a system for detecting the location of an object submerged in a medium having transmission characteristics substantially different from that of the atmosphere by means of radiated electromagnetic energy containing a multiplicity of signals of different frequencies and regardless of the source of said energy;

• means to receive an incident radiation of said electromagnetic energy and the reflection of said radiation by the presence of a submerged object within the range of said system, said reflected radiation containing some of the frequencies of said incident radiation, means to derive from said received incident radiation and said reflected radiation in frequency common to both, means to extend the duration of said received incident radiation, means to compare the field strength of said filtered incident radiation with the field strength of said filtered reflected radiation to determine the relation therebetween, and thereby obtain a measure corresponding substantially to the range of the submerged object.

In a system for detecting the location of an object submerged in a medium having transmission characteristics substantially different than the atmosphere by means of radiated electromagnetic energy containing a multiplicity of signals of different frequencies and regardless of the source of said energy;

• means to receive an incident radiation of said energy and the reflections of said radiation caused by the presence of a submerged object within the range of said system, said reflected radiation containing some of the frequencies of said incident radiation, means to derive from said incident radiation and said reflected radiation a signal frequency common to both, means to extend the duration of said filtered incident radiation of each said frequency to be coincident with said filtered reflected radiation of the corresponding frequency, means to compare the field strength of each said signal frequency of said extended incident radiation with the field strength of the corresponding signal frequency of said reflected radiation to determine the relation therebetween, said relation indicating the range of said submerged object.

In a system for detecting the location of an object submerged in a medium having transmission characteristics substantially different from that of the atmosphere by means of radiated electromagnetic energy containing a multiplicity of signals of different frequencies and regardless of the source of said energy;

• means to receive an incident radiation of said energy and the reflections of said radiation caused by the presence of a submerged object within the range of said system, said reflected radiation containing some of the frequencies of said incident radiation, means to derive from said incident radiation and said reflected radiation a plurality of discrete frequency signals common to both, means to extend the duration of each derived discrete frequency signal of said incident radiation for a time substantially equal to the time difference to the velocity of propagation of said frequency signal in said medium as compared to the atmosphere, and means to compare the field strength of said extended signals of each said discrete frequency of said incident radiation with the field strength of the corresponding frequency signal of said reflected radiation to determine the relation therebetween, said relation indicating substantially the range of said submerged object.