Scanning rangefinder with range to frequency conversion

A system for measuring a distance to a remote object comprising:

• a source for transmitting an optical measurement signal beam to the object;
• a detector for generating an output signal in response to detection of a reflection of said signal beam from the object, said detector output signal being related to an amplitude of said detected reflection;
• an element responsive to the detector output signal for causing said source to continually transmit the measurement signal beam at an amplitude which is inversely related to the amplitude of said detected reflection such that while the amplitude of said detected reflection is a quantitative amount above a threshold level, said element causes said source to continuously transmit the signal beam at an amplitude which is said quantitative amount below said threshold level;
• and while the amplitude of said detected reflection is a quantitative amount below said threshold level, said element causes said source to continuously transmit the signal beam at an amplitude which is said quantitative amount above said threshold level;
• and
• measurement means for measuring a frequency of modulation of said signal beam, said frequency being indicative of a distance from said source to the object.

A method for measuring a distance to a remote object comprising the steps of:

• (a) transmitting an optical measurement signal beam from a source to the object;
• (b) detecting a reflection of said signal beam from the object;
• (c) modulating said signal beam in response to said detected reflection, said modulating step comprising the step of causing said source to continually transmit the measurement signal beam at an amplitude which is inversely related to the amplitude of said detected reflection such that while the amplitude of said detected reflection is a quantitative amount above a threshold level, said element causes said source to continuously transmit the signal beam at an amplitude which is said quantitative amount below said threshold level;
• and while the amplitude of said detected reflection is a quantitative amount below said threshold level, said element causes said source to continuously transmit the signal beam at an amplitude which is said quantitative amount above said threshold level;
• and
• (d) measuring a frequency of modulation of said signal beam, said frequency being indicative of a distance from said source to the object.

A method for measuring a distance to a remote object comprising the steps of:

• (a) transmitting an optical measurement signal beam from a source to the object;
• (b) detecting a reflection of said signal beam from the object;
• (c) modulating said signal beam in response to said detected reflection, said modulating step comprising the steps of:
• (i) causing said source to continually transmit the measurement signal beam at a first amplitude while the amplitude of said detected reflection is at a second amplitude, and
• (ii) causing said source to continually transmit the measurement signal beam at said second amplitude while the amplitude of said detected reflection is at said first amplitude;
• and
• (d) measuring a frequency of modulation of said signal beam, said frequency being indicative of a distance from said source to the object.

A system for deflecting an optical measurement signal beam in two dimensions and for collecting a reflection of said beam from a remote object, said system comprising:

• a first prism means for deflecting, via a refraction angle, said beam and said reflection;
• a rotating means for rotating said first prism about an axis;
• a second prism means for deflecting said beams and said reflection, said second prism means comprising a triangular prism having a mirrored diagonal surface which deflects said beam and said reflection through a 360 degree field of view lying in a plane perpendicular to said axis of rotation, which together with the deflection of the beams and reflection by said first prism means enables a field of view encompassing 360 degrees of azimuth and a number of degrees of elevation equal to twice the refraction angle of said first prism;
• a second rotating means for rotating said second prism about said axis;
• a first control means for rotating said first prism through a first angle at a first rate of speed;
• and
• a second control means for rotating said second prism through a second angle at a second rate of speed, thereby enabling positioning of the transmitted signal beam to any desired position or through any desired pattern within a field of view encompassing 360 degrees of azimuth and said number of degrees of elevation.

A method for deflecting an optical measurement signal beam in two dimensions and for collecting a reflection of said beam from a remote object, said method comprising the steps of:

• deflecting said beam and said reflection through a refraction angle of a first prism;
• rotating said first prism about an axis, said first prism being rotated through a first angle at a first rate of speed;
• deflecting said beam and said reflection through a second prism, said second prism being a triangular prism having a mirrored diagonal surface which deflects said beam and said reflection (through a 360 degree field of view lying in a plane perpendicular to said axis of rotation, which together with the deflection of the beam and reflection by said first prism enables a field of view encompassing 360 degrees of azimuth and a number of degrees of elevation equal to twice the refraction angle of said first prism;
• rotating said second prism about said axis, said second prism being rotated through a second angle at a second rate of speed, thereby enabling positioning of the signal beam to any desired position or through any desired pattern within a field of view encompassing 360 degrees of azimuth and said number of degrees of elevation.