Though Sunrise and Ark Performance have not released any words about it yet.
Official website URL: http://g-twilight-axis.net/
Gundam ACE magazine May 2017 issue teases these 2 visual images that looked like some screenshots from anime trailer is making us feel more excited about this!
Story concept design: Ark Performance
Mechanical Chief Animation Director: Shingo Abe
Art Director: Nakamura TsuyoshiNozomi
Music: Omama Subaru
More info will be provided soon.