The general rule
If a question is primarily targeting the design of electronics (as defined in the FAQ), it is on topic, regardless of the platform on which that design will be used. This platform could be consumer electronics (even though we don't take questions about fixing/troubleshooting consumer electronics), PC motherboards (even though we don't take questions about PC software), or a robot(even though we don't take questions about robotics).
Of course, it could be about a development board or Arduino shield, which we'd instantly recognize as on-topic. However, the topic of the question, not the finished product, determines the scope into which the question falls.
This specific case
On a first glance, I would have said that it's only tagged robotics because the electronics involved are on a robotics platform. Therefore, the tag should be removed and the question admitted. (But read on!)
Adding a GPS sensor to a motor base (system controller)? Sounds like electronics to me! They're doing electronics design, not robotics design, so I say that it can stay on the Robotics vs. Electronics grounds. If they had questions about AI theory/machine learning, mechanics, automation, or other robotics-specific questions, then it's robotics and off-topic.
However, after further reading, they're using MRDS (Microsoft Robotics). I don't see any indication that they intend to use any electronics to make a physical realization of this system at any time. Seriously, a robot driving a car? It's not on topic.