Want to improve your GPS antenna multipath convergence time performance to near survey-grade GNSS levels? Just using this simple steel plate effectively improves simple patch antenna performance to near professional level antenna setups.
The steel disc provides a ground plane for a low cost u-blox ANN-MB-00 antenna and enables centimeter-level positioning when coupled with a L1/L2 capable GNSS receiver such as the ZED-F9P.
The 1.6 mm thick steel plate fits onto the standard ¼-20 UNC camera mounting screw. While it is not the cleanest piece of steel and weighs in at a hefty 0.2 kg, it does provide a solid base to allow a GPS Magnetic Mount Antenna to sit flat on the ground plane while mounted to a tripod.
See also Ublox white paper on using low cost antennas for RTK.
Moer information is available on the website of Sparkfun.