Spacecraft docking sensor system

Sensing apparatus for use in docking a first space vehicle with a second space vehicle, the apparatus comprising:

• means on the first space vehicle for generating electromagnetic radiation having two distinct wavelengths;
• a reflective target located on the second space vehicle, and responsive to only one of the wavelengths;
• means on the first space vehicle for transmitting the radiation, to illuminate the reflective target, of which the exact position and orientation are initially unknown;
• filter means on the first space vehicle, for separating received reflected radiation into two wavelength bands containing the two respective transmitted wavelengths;
• camera means on the first space vehicle, for converting the received and filtered radiation simultaneously into two separate electronic images corresponding to received images in the two wavelength bands;
• and
• image processing means, including means for subtracting the two electronic images, one from the other, to yield an enhanced image of the reflective target, whereby unwanted reflections from the second space vehicle tend to be canceled in the means for subtraction.

A method for forming an image of a reflective target, comprising the steps of:

• generating electromagnetic radiation having two distinct wavelengths;
• transmitting the radiation, to illuminate a reflective target responsive to only one of the wavelengths, and of which the exact position and orientation are initially unknown;
• separating received reflected radiation into two wavelength bands containing the two respective transmitted wavelengths;
• converting the received and filtered radiation simultaneously into two separate electronic corresponding to received images in the two wavelength bands;
• and
• subtracting the two electronic images, one from the other, to yield an enhanced image of the reflective target, whereby unwanted reflections from other objects tend to be canceled by the subtracting step.

A method for sensing space vehicle position and orientation while docking a first space vehicle with a second space vehicle, the method comprising the steps of:

• generating, on the first space vehicle, electromagnetic radiation having two distinct wavelengths;
• transmitting the radiation, from the first space vehicle, to illuminate a reflective target responsive only to on of the wavelengths, and of which the exact position and orientation are initially unknown;
• separating, on the first space vehicle, received reflected radiation into two wavelength bands containing the two respective transmitted wavelengths;
• converting, on the first space vehicle, the received and filtered radiation simultaneously into two separate electronic images corresponding to received images in the two wavelength bands;
• and
• subtracting the two electronic images, one from the other, to yield an enhanced image of the reflective target, whereby unwanted reflections from the second space vehicle tend to be canceled by the subtracting step.