An Anti Satellite active denial system launched against the Navstar or any loe Satellite network would just need 1 small launcher no bigger than the Black Arrow Rocket, which could deliver 100 kg of 2 mm stainless steel ball bearings with a mass of 1.5 grams (approx 45,000 objects all with differing orbits). Now if these bullets were traveling in the opposite direction to the satellites orbital direction the kinetic energy of the 2mm ball bearing with respect to the satellite would be around 0.5*0.0015*(15645^2)= 190KJ or about 10 times the energy of a .50 cal BMG round exiting the end of a gun barrel.

Those 45,000 2 mm ball bearing would be very difficult to track individually using ground based RADAR and would make it extremely difficult to operate satellites at the altitudes the ball bearings were released. It would take just a few days to weeks before Kessler Syndrome became a reality.