I do IPT, so I may not belong here
Needs of a system: Information Technology; including hardware and software. The requirements of the system, for example detailed hardware specifications and/or application and system software (or custom software from programmers).
Objectives: The aims and objectives which will be accomplished (or envisaged to be accomplished) by the system. This can be broad or very specific. The new system will be used in tandem with the needs of the users to fulfill the aims, goals and objectives.
Needs: something required for the system
Objective: something the system
should complete/do/fulfill
If it's irrelevant to SDD, then I'll be quiet