Low power laser sensing
AssigneeIsrael Aerospace Industries Ltd.
InventorsBenjamin Levy, Valery Heymann, Igal Greenberg, Uri Karazi, Amnon Ychye
Life of this patent
Estimating the term…
Abstract
The presently disclosed subject matter includes a laser system and a respective method of detecting a signal reflected from a target illuminated by a modulated CW light source configured to generate a modulated laser signal at a predefined modulation frequency. A signal comprising true laser signal portions reflected from said target, and noise is received; the signal is filtered for selecting laser signal portions at a modulation frequency band; and the true signal portions in the signal are detected, if the energy at the modulation frequency band is greater than a given threshold.
Claims21
A method of detecting a signal reflected from a target, the method comprising:
- receiving light signals by sampling continuous wave (CW) input signals at a sampling rate selected to be greater than a frequency corresponding to predefined frequency bands used for signal modulation, and generating a plurality of samples;
- and
- processing said plurality of samples, said processing including:
- applying filtering to said plurality of samples for dividing said plurality of samples into different frequency bands during a given time window;
- and
- analyzing the divided samples and determining the energy integrated at frequency bands including the energy integrated at a modulation frequency and the energy integrated at frequencies different from the modulation frequency;
- determining a threshold as a function between the energy integrated at frequencies different from the modulation frequency and the energy integrated at the modulation frequency;
- and
- applying said threshold to the divided samples, thereby detecting true signal portions reflected from said target corresponding to the modulation frequency band greater than said determined threshold.
A laser sensor unit operable for detecting a signal reflected from a target illuminated by a modulated CW light source configured to generate a laser signal modulated at a predefined modulation frequency, the laser sensor unit comprising:
- a sensor head associated with at least one processing channel, the sensor head being operable to receive light input comprising true signal portions reflected from said target, and noise;
- said at least one processing channel including:
- a sampler configured to sample the light input being received with a sampling rate which is greater than a frequency corresponding to predefined frequency bands used for signal modulation, and thereby generating a plurality of samples;
- an energy integration module configured to process the plurality of samples and divide the samples into different frequency bands and integrate energy of the divided samples at said different frequency bands during a given time window, said energy integrated at different frequency bands including energy integrated at the modulation frequency and energy integrated at frequencies different from the modulation frequency;
- and
- an energy threshold detector configured for processing said energy integrated at said different frequency bands for determining a threshold as a function between the energy integrated at frequencies different from the modulation frequency and the energy integrated at the modulation frequency, and applying the determined threshold to thereby detect the true signal portions in the signal, corresponding to the modulation frequency band greater than said threshold.
A non-transitory program storage device readable by machine, tangibly embodying a program of instructions executable by the machine to perform method steps of detecting a signal reflected from a target, the method comprising:
- receiving light signals by sampling continuous wave (CW) input signals at a sampling rate selected to be greater than a frequency corresponding to predefined frequency bands used for signal modulation, and generating a plurality of samples;
- processing said plurality of samples, said processing comprising:
- applying filtering to said plurality of samples for dividing said plurality of samples into different frequency bands during a given time window;
- and
- analyzing the divided samples and determining the energy integrated at frequency band including the energy integrated at a modulation frequency and the energy integrated at frequencies different from the modulation frequency;
- determining a threshold as a function between the energy integrated at frequencies different from the modulation frequency and the energy integrated at the modulation frequency;
- and
- applying said threshold to the divided samples thereby detecting true signal portions reflected from said target corresponding to the modulation frequency band greater than said determined threshold.
Dependencies are inferred from the claim text.