Description
Objective: Development of efficient on-board guidance algorithms for autonomous electric propulsion (EP) transfer and validation ona representative Processor In the Loop (PIL).
Targeted Improvements: When existing on-board hardware resources can be used to establish the guidance function on-board, then this will allow to reduce the need for ground station availability and control centre support to compute the attitude guidance thereby reducing related financial cost (for renting of stations and provision of staff) by atleast 80%. Flexibility is also improved opening towards future platform autonomy. In addition it supports collocation.
Description: Typical scenarios for electric propulsion transfer of telecom satellites are based on a period of 3-6 months until the satellite arrives in GEO. During the early and late part of the transfer, the satellite is almost continuously in contact with a ground controlcentre. Ground-based guidance is justified, because of the navigation function being based on ranging measurements and because of the complex algorithms for generating the transfer guidance. It results in extensive costs for ground station time and control centreavailability.
This activity proposes to overcome the need for extensive ground-based support for transfer guidance generation by moving the guidance function on-board.An on-board guidance algorithm would exploit the available GNSS measurements for navigation and run elaborate, robust and high-performing algorithms on the on-board computer to generate the attitude guidance, establishing the optimum EP thrust direction, solar array pointing and any further attitude constraints required to be addressed in the guidance. TheAOCS software will then control the attitude during transfer, removing the need for routine ground-intervention.
In order to make the on-board guidance robust and reliable, new algorithms need to be developed and verified for which the limited computing power on-board is sufficient. Hybridization of analytic methods with limited numerical optimization appears to have such potential.
The proposed work logic is the following:
- Initial trade-off of guidance methods
- Review of available analytic and semi-analytic methods to compute EP transfer guidance.
- Elaboration and testing of algorithm
- Implementation of algorithm in software for full verification on a flight-representative processor
- Extensive testing to demonstrate full functionality
Tender Specifics