System and method for time-to-intercept determination

A method for determining a time-to-intercept for a radiation source, comprising:

• providing irradiance data relating to the radiating source;
• minimizing noise associated with the irradiance data so as to provide usable irradiance data;
• computing the time-to-intercept using the usable irradiance data;
• and
• updating the time-to-intercept computation using updated usable irradiance data derived from the updated irradiance data;
• where, minimizing noise comprises determining a signal-to-noise ratio (SNR) value of each irradiance value and declaring an irradiance value to be a usable irradiance value if the SNR value is greater than a threshold SNR value.

A system for determining a time-to-intercept of a radiation source, comprising:

• a detection system detecting successive irradiance values of the radiation source;
• a calculation module that calculates the time-to-intercept using the irradiance values output from said detection system;
• and
• an update module that updates the time-to-intercept calculation using irradiance values that are advanced in time;
• said detection system comprising a noise module for determining a signal-to-noise ratio (SNR) value of each detected successive irradiance value and for outputting to said calculation module only those irradiance values having a SNR value that is greater than a threshold SNR value.

A time-to-intercept processor for determining a time-to-intercept of a radiation source, comprising:

• means for providing irradiance values of the radiance source successively in time;
• means for reducing noise present in the irradiance values to produce usable irradiance values, said noise reducing means comprising means for determining a signal-to-noise ratio (SNR) value of each irradiance value and declaring an irradiance value to be a usable irradiance value if the SNR value is greater than a threshold SNR value;
• and
• means for calculating the time-to-intercept using the usable irradiance values.

A method for determining a time-to-intercept during a time-of-flight of a radiating source, comprising:

• computing a plurality of irradiance values from measurements made from the radiating source, each computation of the irradiance value using a substantially constant value of acceleration a of the radiating source;
• reducing noise in the irradiance values to provide usable irradiance values;
• and
• computing the time-to-intercept based on usable irradiance values.

A method for determining a time-to-intercept during a time-of-flight of a radiating source, comprising:

• computing, using a substantially constant value of acceleration a of the radiating source, a measured amplitude Z(t) of an irradiance value H(t) from a measurement made from the radiating source;
• determining a ratio of the measured amplitude to a change in amplitude dZ(t)/dt;
• and
• relating the determined ratio dZ(t)/dt to the time-to-intercept of the radiating source.