Embedded Star Sensor Software

 

Sankya’s  Star Based Precision Aviation Software is an embedded software for on-orbit  estimation of satellite direction parameter using data of the star location and  image. It was developed for a 16-bit processor and the application has an  optimized organization of star catalog for low memory and fast access, a  quaternion based parameter structure to avoid trigonometric functions and  singularity points, a geometric tracking method for fast and error free star  identification and simple attitude propagation model. Sankya’s solution is made  such that it is operational on two satellites. Designed for 24x7 operations,  these applications are operational onboard live satellites.

The attitude of a satellite is the orientation with  respect to a definite frame of reference and Sankya uses the stellar bodies to  determine this. The external forces generally compel the attitude dynamics to  change. But Sankya’s software solution uses attitude determination by using  star sensors to ascertain the new and current attitude. By doing so, the  readings are always accurate in spite of shift in position.


Different  kinds of sensors function by generating outputs that reflect by taking into  consideration the rate of change in attitude. They work by gaining information  of the initial attitude or external data in order to use them to determine the  current attitude. In order to avoid any errors due to noise etc, Sankya uses  absolute attitude sensors.

The software uses a star sensor, an  optical device that can determine the position of the star using a camera or a  high quality photocell. Sankya’s software solution takes into accounts all  possibilities of inaccuracies and strives at designing a solution that can  foresee all of it and overcome it. The sensors don’t fall prey to sunlight  reflected off other bodies etc. Though they work because of high sensitivity,  they are built to identify the target focus and not get confused. The solution  also ensures that it avoids errors of high spatial frequency, low spatial  frequency, temporal errors etc besides the expected optical errors like chromatic  aberration, spherical aberration and more. Star identification algorithm also  has many potential sources of confusion like the planets, supernovas, comets,  the bimodal aspect of the point spread functionality of nearby stars etc.  Sankya, being a high-tech tracking solution uses entire star field database to  determine satellite orientation as against smaller solution that uses limited  star access. This helps removing problematic stars that could have obvious  magnitude variability, or a location that states unreliability or color index  uncertainty and more. In such cases Sankya’s software ensures that the reading of  the location and position of the satellite is read without errors.

With  this software one is assured of a level of aviation control and development  that is completely unmatched.

 

 

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