I have a GPS PCB which has regular USB pinouts (GND, +5V, DATA- and DATA+), but in addition has one stranded wire which is connected to USB type A plug. Marked as "USB connector" on the image:
What is the purpose of this stranded wire? If this is for shielding purposes, then why is it connected in both ends? Doesn't this create a "shielding loop"? In addition, if this matters, there is an aluminium-foil shielding around all five wires:
..and this aluminium-foil is also connected to USB plug, i.e. aluminium-foil and stranded wire are electrically connected.