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A blade tracking system including a detector having one or more sensors to detect radiation from at least one field of view of the detector, the one or more sensors generating signals based on changes in incident radiation to the one or more sensors as a rotor blade passes the field of view, and a p

A blade tracking system including a detector having one or more sensors to detect radiation from at least one field of view of the detector, the one or more sensors generating signals based on changes in incident radiation to the one or more sensors as a rotor blade passes the field of view, and a processor to determine a pass time for the rotor blade to pass through the at least one field of view based on the generated signals.

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1. A rotor blade tracking system, comprising: a detector housing having a pair of detector units, each detector unit of the pair of detector units having a sensor to generate signals based on changes in incident radiation to the respective sensor as a rotor blade passes a field of view of the respec

1. A rotor blade tracking system, comprising: a detector housing having a pair of detector units, each detector unit of the pair of detector units having a sensor to generate signals based on changes in incident radiation to the respective sensor as a rotor blade passes a field of view of the respective detector unit, each detector unit of the pair of detector units including: at least a first chamber and a second chamber,the first and second chamber defined by a plurality of side walls common to the first and second chambers and a dividing wall separating the first and second chambers,an entrance aperture configured to pass incident radiation from outside the detector unit into the first chamber,an internal aperture formed in the dividing wall configured to pass the incident radiation from the first chamber into the second chamber,the entrance aperture having a center that is located a first distance from one side wall of the plurality of side walls and the internal aperture having a center that is located a second distance from the one side wall of the plurality of side walls,the entrance and internal apertures being positioned in a staggered manner such that the first distance, is not equal to the second distance to create an optics path from the entrance aperture through the internal aperture to the sensor to define the field of view of the detector unit; anda processor configured to calculate a pass time for the rotor blade to pass through both fields of view based on a time difference between selected locations of signals generated when the rotor blade passes through each field of view, respectively. 2. The rotor blade tracking system of claim 1, wherein for each detector unit of the pair of detector units: the dividing wall is a baffle, and wherein the entrance and internal apertures are positioned such that a portion of the incident radiation moves through the optics path to the sensor unattenuated while the remainder of the incident radiation is attenuated in the first chamber and does not enter the second chamber via the optics path. 3. The rotor blade tracking system of claim 1, wherein each of the generated signals is a pulse signal having a leading edge and a trailing edge as the rotor blade enters and exits the respective field of view. 4. The rotor blade tracking system of claim 3, wherein the processor is configured to select a location between the leading and trailing edges based on a leading edge start time and a trailing edge end time of each of the generated signals, and to calculate the pass time for the rotor blade to pass through both fields of view based on a time difference between the respective selected locations between the leading edges and the trailing edges of each respective generated signal. 5. The rotor blade tracking system of claim 3, wherein the processor is configured to calculate the pass time based on a time difference between respective averages of measured times between the leading and trailing edges. 6. The rotor blade tracking system of claim 5, wherein the averages are the midpoints of the measured times between the leading and trailing edges. 7. The rotor blade tracking system of claim 1, wherein the selected locations are midpoints between leading edges and trailing edges of each respective generated signal. 8. The rotor blade tracking system of claim 7, wherein the processor is configured to determine a threshold level for each of the generated signals based on an amplitude of the respective generated signals, and the processor calculates a midpoint for each generated signal based on the leading edge start time and the trailing edge end time at the threshold level, respectively. 9. The rotor blade tracking system of claim 8, wherein the threshold level is adjusted based on the amplitude of prior signals of the generated signals. 10. The rotor blade tracking system of claim 1, wherein the processor determines a height of the rotor blade based on the pass time. 11. The rotor blade tracking system of claim 10, wherein the rotor blade is one of a plurality of rotor blades, and wherein the processor is configured to calculate the pass time for each rotor blade of the plurality of rotor blades and to compare the pass times of different rotor blades of the plurality of rotor blades to compute lead/lag characteristics of a given rotor blade of the plurality of rotor blades relative to another rotor blade of the plurality of rotor blades. 12. The rotor blade tracking system of claim 1, wherein each of the generated signals contains a component corresponding to a level of background radiation incident on a respective sensor of the sensors, and the rotor blade tracking system further comprises a background subtraction module to adjust the respective generated signal based on changes in the level of background radiation before the pass time is calculated. 13. The rotor blade tracking system of claim 1, wherein the processor is configured to determine a time period at which the generated signals are at a maximum or minimum. 14. The rotor blade tracking system of claim 1, wherein the processor includes gain electronics to enhance signal levels of the generated signals. 15. The rotor blade tracking system of claim 14, wherein the processer is configured to determine an amplitude of each of the generated signals, and adjusts the gain electronics based on the amplitude. 16. The rotor blade tracking system of claim 1, wherein the processor includes a low pass filter to remove noise from an output of each sensor. 17. The rotor blade tracking system of claim 1, wherein the processor includes a notch filter to remove noise of a specific frequency from the generated signals. 18. The rotor blade tracking system of claim 1, further comprising a radiation source to illuminate the blade when the incident radiation reaches a predetermined level. 19. The rotor blade tracking system of claim 1, wherein the processor is configured to collect data from a plurality of rotations and to use statistical timing correlations to distinguish a true blade event from a false blade event. 20. The rotor blade tracking system of claim 19, wherein the processor is configured to determine a blade track based on the collected data. 21. The rotor blade tracking system of claim 1, wherein the generated signals are digital signals, and wherein the selected locations of the generated signals are between maxima and minima of the digital signals. 22. The rotor blade tracking system of claim 1, wherein the processor is configured to calculate a pass time for the rotor blade to pass through both fields of view based on a time period between which the generated signals from the sensors are at maxima or minima. 23. The rotor blade tracking system of claim 1, wherein the generated signals are digital signals, and the processor is configured to calculate the pass time based on curve-fitting and/or using digital constant-fraction discriminators. 24. The rotor blade tracking system of claim 1, wherein the processor comprises a field-programmable gate array (FPGA) to curve fit data from the generated signals to find center times of pulse signals. 25. The rotor blade tracking system of claim 1, wherein the pass time is based on rotor blade pass event times through the respective optics paths forming the fields of view. 26. The system of claim 1, wherein the fields of view combine to form a cone-shaped field of known dimensions, and wherein the processor calculates a time in the cone-shaped field for the rotor blade based on the time differences between the generated signals. 27. The system of claim 26, wherein the fields of view diverge from each other extending from the entrance apertures. 28. A rotor blade tracking system, comprising: a detector housing having a pair of detector units, each detector unit of the pair of detector units having a sensor to generate signals based on changes in incident radiation to the respective sensor as a rotor blade passes a field of view of the respective detector unit, each detector unit of the pair of detector units including: at least a first chamber and a second chamber,the first and second chamber defined by a plurality of side walls common to the first and second chambers and a dividing wall separating the first and second chambers,an entrance aperture configured to pass incident radiation from outside the detector unit into the first chamber,an internal aperture formed in the dividing wall configured to pass the incident radiation from the first chamber into the second chamber,the entrance aperture having a center that is located a first distance from one side wall of the plurality of side walls and the internal aperture having a center that is located a second distance from the one side wall of the plurality of side walls,the entrance and internal apertures being positioned in a staggered manner such that the first distance is not equal to the second distance to create an optics path from the entrance aperture through the internal aperture to the sensor to define the field of view of the detector unit; andthe optics path of each detector unit of the pair of detector units being aimed at an angle so that the respective fields of view of each detector unit of the pair of detector units diverge from one another outside the detector housing, the incident radiation including background radiation incident to the sensors;a background subtraction module to remove at least a portion of a signal associated with the background radiation to define a background subtracted signal; anda processor configured to calculate a pass time for the rotor blade to pass through both fields of view based on a time difference between selected locations of signals generated when the rotor blade passes through each field of view, respectively. 29. A method of tracking a rotor blade, comprising: detecting incident radiation on a pair of sensors respectively provided in a pair of detector units in a detector housing as a rotor blade passes fields of view extending from the respective detector units, wherein for each detector unit of the pair of detector units: at least a first chamber and a second chamber,the first and second chamber defined by a plurality of side walls common to the first and second chambers and a dividing wall separating the first and second chambers,an entrance aperture configured to pass incident radiation from outside the detector unit into the first chamber,an internal aperture formed in the dividing wall configured to pass the incident radiation from the first chamber into the second chamber,the entrance aperture having a center that is located a first distance from one side wall of the plurality of side walls and the internal aperture having a center that is located a second distance from the one side wall of the plurality of side walls,the entrance and internal apertures being positioned in a staggered manner such that the first distance is not equal to the second distance to create an optics path from the entrance aperture to the sensor of the detector unit to define the field of view of the detector unit;the optics path of each detector unit of the pair of detector units being aimed at an angle so that the respective fields of view of each detector unit of the pair of detector units diverge from one another outside the detector housing;generating signals based on changes in the detected incident radiation to the pair of sensors; andcalculating a pass time for the rotor blade to pass through both fields of view based on a time difference between selected locations of signals generated when the rotor blade passes through each field of view, respectively. 30. The method of claim 29, wherein the selected locations of the generated signals are between leading and trailing edges of each generated signal based on a leading edge start time and a trailing edge end time of the leading edge and trailing edge, respectively. 31. The method of claim 30, further comprising: calculating a threshold level for each generated signal based on an amplitude of each generated signal, respectively; andcalculating a midpoint for each generated signal based on the leading edge start time and the trailing edge end time at the threshold level, respectively. 32. The method of claim 29, wherein the generated signals contain a component corresponding to a level of background radiation, the method further comprising: adjusting the respective generated signals to correspond to changes in the level of background radiation before the pass time is calculated. 33. The method of claim 29, wherein the blade rotates a plurality of times with respect to both fields of view, the method further comprising: correlating the generated signals to a corresponding rotation of the blade, respectively, such that signals generated during a same rotation are used to calculate the pass time.