Coherent optical radar processor

Claim 2

In a coherent radar system having means for transmitting radar pulses and receiving radar echoes from said pulses wherein said received echoes represent radar data, a radar processing system for extracting information from said radar data about moving targets in the presence of high background clutter comprising: a. optical recording means sensitive to said radar echoes for storing said radar data and comprising: 1. means for generating an optical beam, 2. optical modulating means in the path of the optical beam and responsive to the radar echoes for modulating the beam, and 3. an optical recording medium sensitive to the modulated beam for recording said radar data; and b. optical processing means for processing said stored data in such a way to emphasize said moving targets over said background clutter, whereby said moving targets are distinguished from said background clutter, said optical processing means including optical means for producing an optical display of the Fourier transform of the stored radar data.

Claim 3

optical modulating means in the path of the optical beam and responsive to the radar echoes for modulating the beam, and

Claim 4

optical modulating means in the path of the optical beam and responsive to the radar echoes for modulating the beam, and

Claim 5

The radar processing system of claim 1 wherein said optical beam is a coherent light beam, and wherein said optical recording means comprises: a. driving means for advancing said optical recording medium; and b. scanning means for scanning said modulated beam across said recording medium in a direction transverse to its driven direction, whereby said radar data is stored on said optical recording medium.

Claim 6

The optical recording means of claim 2 further comprising: a. comparator means coupled between the output of said optical modulating means and said received radar echoes for generating an output signal representing the difference between these signals, and b. voltage driving means coupled to said optical modulating means and sensitive to said output signal for controlling said optical modulating means whereby the output of said modulating means is linearized.

Claim 7

an optical recording medium sensitive to the modulated beam for recording said radar data; and b. optical processing means for processing said stored data in such a way to emphasize said moving targets over said background clutter, whereby said moving targets are distinguished from said background clutter, said optical processing means including optical means for producing an optical display of the Fourier transform of the stored radar data.

Claim 8

an optical recording medium sensitive to the modulated beam for recording said radar data; and b. optical processing means for processing said stored data in such a way to emphasize said moving targets over said background clutter, whereby said moving targets are distinguished from said background clutter, said optical processing means including optical means for producing an optical display of the Fourier transform of the stored radar data.

Claim 9

The optical recording means of claim 2 wherein said scanning means comprises a beveled scanning mirror.

Claim 10

The optical recording means of claim 2 further comprising: a. timing means coupled to said scanning means and said radar pulses for synchronizing said scanning means with said radar pulses, whereby the radar data may be recorded in a predetermined manner on said optical recording medium.

Claim 11

The radar processing system of claim 1 wherein: a. said radar data is stored in vertical and horizontal directions, the radar data in said vertical direction representing the radar echoes from one radar pulse while traveling from the nearest to the farthesT range, and the radar data in the horizontal direction representing similar data from successive radar pulses; and b. said optical means produces from said stored data the Fourier spectrum of the Doppler frequency shift in the horizontally stored radar data.

Claim 12

The radar processing system of claim 6 wherein said optical processor comprises: a. a source of collimated, coherent light for producing a beam of light; b. driving means for advancing said stored radar data through said beam of light in a horizontal direction, whereby said radar data modulates said beam; c. a lens system placed in said beam after the entry of said radar data for focusing said modulated beam into images; whereby the Doppler shift of said horizontally recorded data determines one directional displacement of said displayed image and said vertically recorded data determines the other directional displacement of said displayed image.

Claim 13

The optical processor of claim 7 further comprising detector means for attenuating said images derived from said background clutter.

Claim 14

In a coherent radar system having means for transmitting radar pulses and receiving radar echoes from said pulses wherein said received echoes represent radar data, said radar pulses being transmitted at such a frequency that radar echoes from several pulses may be received in the same time interval thereby creating range ambiguities in the radar data as to these echoes, a radar processing system for resolving said range ambiguities comprising: a. an optical recorder for storing said radar data, said storage taking place in vertical and horizontal directions, the radar data in said vertical direction representing the radar echoes from one radar pulse while traveling from a minimum radar range to a first ambiguous range, and the radar data in the horizontal direction representing similar data from successive radar pulses; b. timing means for varying the time period between successive radar pulses according to the progression t, t+ Delta , t+2 Delta , . . . t+n Delta , where t is the time between the first and second pulses, Delta is a fixed time interval, and n is a predetermined number, said progression being repeated once completed, whereby all stored radar data of a given range ambiguity falls along a line at a predetermined angle; and c. a multichannel optical processor for processing said stored data, whereby each channel processes one ambiguous range interval, said optical processor including optical means for producing an optical display of the Fourier transform of the stored radar data.

Claim 15

In a coherent radar system having means for transmitting radar pulses and receiving radar echoes from said pulses wherein said received echoes represent radar data, said radar pulses being transmitted at such a frequency that radar echoes from several pulses may be received in the same time interval thereby creating range ambiguities in the radar data as to these echoes, a radar processing system for resolving said range ambiguities comprising: a. an optical recorder for storing said radar data, said storage taking place in vertical and horizontal directions, the radar data in said vertical direction representing the radar echoes from one radar pulse while traveling from a minimum radar range to a first ambiguous range, and the radar data in the horizontal direction representing similar data from successive radar pulses; b. timing means for varying the time period between successive radar pulses according to the progression t, t+ Delta , t+2 Delta , . . . t+n Delta , where t is the time between the first and second pulses, Delta is a fixed time interval, and n is a predetermined number, said progression being repeated once completed, whereby all stored radar data of a given range ambiguity falls along a line at a predetermined angle; and c. a multichannel optical processor for processing said stored data, whereby each channel processes one ambiguous range interval, said optical processor including optical means for producing an optical display of the Fourier transform of the stored radar data.

Claim 16

In a coherent radar system having means for transmitting radar pulses and receiving radar echoes from said pulses wherein said received echoes represent radar data, a method for extracting information from said radar data about moving targets in the presence of high background clutter comprising the steps of: a. optically storing said radar echoes by generating a recording optical beam, modulating the beam in proportion to the received radar echoes, and recording the modulated beam on an optical recording medium; and b. optically processing said optically recorded data in such a way to emphasize said moving targets over said background clutter, whereby said moving targets are distinguished from said background clutter, said processing step including optically producing the Fourier transform of the recorded data.

Claim 17

In a coherent radar system having means for transmitting radar pulses and receiving radar echoes from said pulses wherein said received echoes represent radar data, a method for extracting information from said radar data about moving targets in the presence of high background clutter comprising the steps of: a. optically storing said radar echoes by generating a recording optical beam, modulating the beam in proportion to the received radar echoes, and recording the modulated beam on an optical recording medium; and b. optically processing said optically recorded data in such a way to emphasize said moving targets over said background clutter, whereby said moving targets are distinguished from said background clutter, said processing step including optically producing the Fourier transform of the recorded data.

Claim 18

The method of claim 10 wherein the recording beam is a coherent light beam, and wherein said step of optically recording comprises the steps of: a. advancing the optical recording medium; and b. scanning said modulated recording beam across said recording medium in a direction transverse to its driven direction, whereby said radar data is stored on said optical recording medium.

Claim 19

The method of claim 10 wherein said optical processing step comprises the steps of: a. generating a processing beam of collimateD, coherent light; b. advancing said recorded radar data through said processing beam of light, whereby said recorded radar data modulates said beam; c. focusing said modulated processing beam into images; and d. optically displaying said images.

Claim 20

The method of claim 12 further comprising the step of attenuating those images derived from said background clutter.