The whole point of the device is to be portable.
It just is not as portable as we would like it for most applications, yet.
The first GPS units were much bigger, and took more power than the current ones.
I remember working on the "Carousel IV" in the 70s, for commercial aviation. The accelerometers were mounted on a rotating platform, a carousel, to improve the accuracy. By rotating, the errors in the acceleration signal would somewhat cancel out. The device was a bit larger than the micromachined accelerometer chips in your cell phone.
The developers were quite proud that the device allowed an airplane to fly from Europe to LA, and only miss the airport by a mile, or so.
The first units weight about 40 pounds, at least the ones I work on. Big black box.... The antennas were huge too.