Navigation initialization with a celestial navigation system

A system comprising:

• a reference oscillator to generate timing signals;
• an altitude reference system to generate altitude information;
• and
• a celestial navigation system (CNS) including,
• a star tracker configured to determine an orientation of the star tracker with respect to an earth centered inertial (ECI) frame, and
• an inertial sensor assembly (ISA) used to determine at least an attitude to a local vertical frame;
• a controller configured to generate an initialization signal using the timing signals generated by the reference oscillator, the altitude information generated from the altitude reference system, and at least one output of the CNS;
• a memory configured to at least store operating instructions implemented by the controller;
• a navigation system in communication with the controller, the generated initialization signal configured to initialize the navigation system;
• and
• a vehicle control system configured to control operation of an associated vehicle based at least in part on an output of the navigation system.

A method of initializing a navigation system with a celestial navigation system, the method comprising:

• computing a star tracker attitude with a star tracker;
• computing a platform level using the computed star tracker attitude;
• computing earth orientation for a world geodetic system (WGS) model using coordinated universal time (UTC) and the computed platform level;
• computing orientation of an earth frame with respect to a local vertical (LV) using the computed earth orientation of the WGS model;
• solving latitude and longitude using the computed orientation of the earth frame with respect to the LV;
• forming a position vector using the solved latitude, the solved longitude, and a reference altitude;
• and
• initializing the navigation system based on the formed position vector.