Method and system for measurement rejection in aided navigation

A system comprising:

• at least one processor onboard a vehicle;
• an aiding source onboard the vehicle and operatively coupled to the at least one processor;
• and
• one or more inertial sensors onboard the vehicle and operatively coupled to the at least one processor;
• wherein the at least one processor includes a set of processing modules comprising:
• a prediction module operative to propagate estimated vehicle navigation error states;
• a residual computation module in operative communication with the prediction module and the aiding source, the residual computation module operative to compute a measurement residual and a measurement residual variance, based on at least one aiding measurement from the aiding source and the estimated vehicle navigation error states from the prediction module;
• a measurement monitoring module in operative communication with the residual computation module, the measurement monitoring module comprising:
• a measurement monitor selection switch operative to select between a normalized measurement residual monitor, and a Chi squared measurement monitor;
• wherein when selected, the normalized measurement residual monitor is operative to perform a first aiding measurement validation process comprising:
• determining whether a normalized measurement residual is less than a first user selected threshold;
• wherein if the normalized measurement residual is less than the first user selected threshold, then providing an indication that the at least one aiding measurement is valid;
• wherein if the normalized measurement residual is not less than the first user selected threshold, then providing an indication that the at least one aiding measurement is invalid;
• wherein when selected, the Chi squared measurement monitor is operative to perform a second aiding measurement validation process comprising:
• determining whether a measurement residual error squared is less than a second user selected threshold;
• wherein if the measurement residual error squared is less than the second user selected threshold, then providing an indication that the at least one aiding measurement is valid;
• wherein if the measurement residual error squared is not less than the second user selected threshold, then providing an indication that the at least one aiding measurement is invalid;
• and
• a correction module in operative communication with the measurement monitoring module, the correction module configured to update the estimated vehicle navigation error states based on the first or second aiding measurement validation processes.