Heterodyne measurement device and method

A method of measuring a distance between a reference point and an object, comprising the steps of:

• providing a continuous measurement beam for a predetermined time period, a continuous reference beam for the predetermined time period, an intensity modulated measurement beam, and an intensity modulated reference beam;
• directing the continuous measurement beam and the intensity modulated measurement beam from the reference point toward the object to produce a reflected continuous measurement beam and a reflected intensity measurement beam;
• and
• combining the reflected continuous measurement beam and the continuous reference beam to produce a first beat signal and for combining the reflected intensity modulated measurement beam and the intensity modulated reference beam to produce a second beat signal;
• integrating the first beat signal over the predetermined time period to produce a first integration value and integrating the second beat signal to produce a second integration value;
• and
• determining the distance between the reference point and the object in accordance with the first and second integration values.

A method of measuring a distance between a reference point and an object, comprising:

• a first step of providing a continuous measurement beam for a predetermined time period and a continuous reference beam for the predetermined time period;
• a second step of directing the continuous measurement beam from the reference point toward the object to produce a reflected continuous measurement beam;
• a third step of combining the reflected continuous measurement beam and the continuous reference beam to produce a first beat signal;
• a fourth step of integrating the first beat signal over the predetermined time period to produce a first integration value;
• a fifth step of providing an intensity modulated measurement beam and an intensity modulated reference beam;
• a sixth step of directing the intensity modulated measurement beam from the reference point toward the object to produce a reflected intensity modulated measurement beam;
• a seventh step of combining the reflected intensity modulated measurement beam and the intensity modulated reference beam to produce a second beat signal;
• an eighth step of integrating the second beat signal to produce a second integration value;
• and
• a ninth step of determining the distance between the reference point and the object in accordance with the first and second integration values.