A fan on twitter went and visited a park in Tokyo that they thought was similar to to the park that appeared in episodes 3 and 4 of Symphogear. Thanks to some pictures and a thorough analysis, it seems that Yoyogi Park in Tokyo actually was the base design for the location featured in Symphogear. But you can judge for yourself, here's the translation of their tweets w/ pictures:
Right! Today I figured I would talk about finding the Symphogear park.
This is the design page for the park from episodes 3 and 4!
It's here, isn't it?
That's right, it's Yoyogi Park. When I first saw it in the Design Works book, I thought it seemed really similar to Yoyogi park, but I wasn't sure until I actually went and saw it for myself.
The Japanese style building in the design is the Meiji Shrine in reality, and marked just in the middle of the design is a pond, which Yoyogi Park has in the same place.
Then there's the subway where 'Bikki fought with the grape Noise. After she gets off the phone with Miku and the Noise appear just below the stairway, that's probably this place right here.
Plus the scene when the grape Noise appears from below ground right in the middle of the park, the subway that runs to Yoyogi Park station does actually run right underneath the park.
This place is similar to the area where Chris fought against Tsubasa. It's dark in the picture so you can't quite tell, but around the circumference are a bunch of different trees, which makes it seem authentic.
Since Symphogear is kind of futuristic I never really considered if any of the designs might be real life places, so this is pretty awesome and definitely an impressive find! You can read more about Yoyogi Park at wikipedia. It's definitely a spot to put on your vacation list if you're ever in Japan!