| 摘要 |
A multi-ladar sensor system is proposed for operating in dense environments where many ladar sensors are transmitting and receiving burst mode light in the same space, as may be typical of an automotive application. The system makes use of several techniques to reduce mutual interference between independently operating ladar sensors. In one embodiment, the individual ladar sensors are each assigned a wavelength of operation, and an optical receive filter for blocking the light transmitted at other wavelengths, an example of wavelength division multiplexing (WDM). Each ladar sensor, or platform, may also be assigned a pulse width selected from a list, and may use a pulse width discriminator circuit to separate pulses of interest from the clutter of other transmitters. Higher level coding, involving pulse sequences and code sequence correlation, may be implemented in a system of code division multiplexing, CDM. A digital processor optimized to execute mathematical operations is described which has a hardware implemented floating point divider, allowing for real time processing of received ladar pulses, and sequences of pulses. |
| 主权项 |
1. A ladar system comprising:
a first ladar sensor and a second ladar sensor; said first ladar sensor having a laser transmitter with a pulsed laser light output transmitting light at a first wavelength through a diffusing optic for illuminating a scene in a field of view of said first ladar sensor, a time zero reference circuit having a time zero reference output, said time zero reference output adapted to signal the beginning of the pulsed laser light transmission, receiving optics for collecting and conditioning the pulsed laser light reflected from said scene in the field of view, a receive filter which receives light at said first wavelength and transmits light at said first wavelength and blocks light at a second wavelength, a two dimensional array of light sensitive detectors positioned at a focal plane of said receiving optics, and receiving light filtered through said receive filter at said first wavelength, and each of said light sensitive detectors with an output producing an electrical response signal from a reflected portion of said pulsed laser light output, a detector bias circuit connected to a voltage distribution grid of said array of light sensitive detectors, a readout integrated circuit with a clock circuit and a plurality of unit cell electrical circuits, each of said unit cell electrical circuits having an input connected to said clock circuit and another input connected to one of said light sensitive detector outputs, each unit cell electrical circuit having an electrical response signal amplifier, a range measuring circuit connected to the output of each of said electrical response signal amplifiers, said range measuring circuit further connected to the time zero reference output, and adapted to produce a range measurement for each light sensitive detector based on the number of clock cycles occurring between the time zero reference output and the time of arrival of the electrical response signal, said second ladar sensor having a laser transmitter with a pulsed laser light output transmitting light at a second wavelength through a diffusing optic for illuminating a scene in a field of view of said second ladar sensor, a time zero reference circuit having a time zero reference output, said time zero reference output adapted to signal the beginning of the pulsed laser light transmission, receiving optics for collecting and conditioning the pulsed laser light reflected from said scene in the field of view, a receive filter which receives light at said second wavelength and transmits light at said second wavelength and blocks light at said first wavelength, a two dimensional array of light sensitive detectors positioned at a focal plane of said receiving optics, and receiving light filtered through said receive filter at said second wavelength, and each of said light sensitive detectors with an output producing an electrical response signal from a reflected portion of said pulsed laser light output, a detector bias circuit connected to a voltage distribution grid of said array of light sensitive detectors, a readout integrated circuit with a clock circuit and a plurality of unit cell electrical circuits, each of said unit cell electrical circuits having an input connected to said clock circuit and another input connected to one of said light sensitive detector outputs, each unit cell electrical circuit having an electrical response signal amplifier, a range measuring circuit connected to the output of each of said electrical response signal amplifiers, said range measuring circuit further connected to the time zero reference output, and adapted to produce a range measurement for each light sensitive detector based on the number of clock cycles occurring between the time zero reference output and the time of arrival of the electrical response signal. |
