Ladar Sensor Wavelength and Pulse Discrimination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In dense environments with multiple LADAR sensors operating simultaneously, there is a high probability of spurious light pulses from other sensors causing confusion and false range measurements, which existing technologies have not adequately addressed.
Innovation Solution
A LADAR system is designed with multiple LADAR sensors using discrete laser wavelengths, pulse width discrimination, and digital encoding of a vehicle identification number in laser pulses to prevent spurious responses, allowing for independent operation and accurate range measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple LADAR sensors operate simultaneously in a dense environment, then the system can provide comprehensive 3-D imaging coverage, but spurious light pulses from other sensors cause confusion and false range measurements
Solution Approach 1:
The patent applies parameter changes by assigning unique combinations of wavelength, pulse width, and digital code to each LADAR sensor. This allows the system to maintain comprehensive coverage while distinguishing between sensors through multiple parameters, preventing spurious pulse confusion and ensuring measurement reliability.
Solution Approach 2:
The patent introduces an intermediary identification system using digital codes embedded in laser pulses. This intermediary mechanism allows receiving sensors to distinguish between their own transmitted pulses and those from other sensors, resolving the confusion caused by simultaneous operation in dense environments.
2Measurement precision
If discrete laser wavelengths and pulse width discrimination are used to reduce spurious pulses, then measurement accuracy improves, but system complexity increases
Solution Approach 1:
The patent merges multiple discrimination methods (wavelength filtering, pulse width discrimination, and digital code verification) into a unified identification system. This combined approach achieves high measurement precision while managing system complexity through integrated processing in the focal plane array and associated electronics.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively reduces the probability of false object and range measurements by using a combination of wavelength diversity, pulse width discrimination, and digital encoding, enabling accurate collision avoidance and navigation in dense LADAR environments.
Implementation Method 1
a laser transmitter with a pulsed laser light output transmitting light at a first wavelength through a diffusing optic
Implementation Method 2
a receive filter which receives light at said first wavelength and transmits light at said first wavelength and blocks light at a second wavelength
Implementation Method 3
each of said light sensitive detectors with an output producing an electrical response signal from a reflected portion of said pulsed laser light output
Implementation Method 4
A range measuring circuit is connected to the output of each of said electrical response signal amplifiers and further connected to the time zero reference output, and is 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
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
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.