[marvin]

This sattelite was some 8000kgs, vs. 4000-ish kgs for the previous-generation GPS satellites, if I remember correctly.

[Roritharr]

Any idea why their weight increased so much?

[nradov]

The latest generation of GPS satellites has more antennas and more powerful transmitters. This improves signal reception and reduces the impact of jamming.

[walrus01]

GPS as received by a small hockey-puck sized antenna is a VERY weak signal, like -140 to -150dB. It only works because the channel size is so narrow and the modulation is very rudimentary. Having a satellite with much larger photovoltaic arrays and really powerful transmitters is one method to overcome regional jamming.

[tgsovlerkhgsel]

I wouldn't be surprised if the satellites had additional, classified capabilities.