Bio-inspired navigation algorithm for GPS denial modes

The wide use of the Global Positioning System (GPS) for navigation has been persistent for a long time. However, in today's scenario when technologies are advancing the accuracy of positioning systems, there are various new threats and challenges emerging. The signal receivers for positioning systems are prone to spoofing. This external interference in the system is usually done by feeding false signals to the receiver. Though the dead reckoning method is still in use, any interference with GPS can still lead to disaster. Insects and birds are known to use solar position for guidance and it is widely accepted by researchers that some birds, such as pigeons, use solar position in their homing flight. There are similar studies performed on honeybees and monarch butterflies. The use of solar position by these insects and birds brings up the question of whether a mathematical model can be used to replicate the results for aircraft navigation, and can a bio-inspired navigation algorithm like this be implemented? Solar position algorithms are already in wide use. The solar position algorithms available calculate the azimuth and zenith/incidence angles for the solar position at any given point of time when the position of the observer is known. The objective for navigation is to find an observer's position from solar position to present an alternative to GPS for navigational use. This document proposes a method for calculating the observer's position when the azimuth and zenith/incidence angles for solar position, attitude of aircraft and time are known. The approach proposed is that the position of the observer can be calculated by reversing the ENEA algorithm where instead of calculating the solar position using an observer's position, one will be calculating the position of the observer from solar position and time. The study includes the comparison of the calculated position of a UAS using the proposed method with the onboard GPS readings for both the ideal and the mimicked sensor accuracies for the position of the sun.