Many hardware companies have settled with Microsoft over their use of Android, but Motorola -- which Google bought this year -- is fighting a range of patent issues with Microsoft in courts in the United States and Germany.
In the latest move, Microsoft said in a court in Munich that it plans to add Google as a defendant in a case in which it claims a mapping feature on Motorola phones infringes one of its patents.
"It became necessary to add Google to this particular case because Motorola maintains that it lacks sufficient information about actions occurring on Google's servers," said a Microsoft spokesperson in an e-mailed statement on Friday.
Google signaled it would defend itself.
"We want to focus on innovation, not litigation, but we'll vigorously defend against any amended complaint Microsoft files," Google's Deputy General Counsel Allen Lo said in an emailed statement.
The patent in question defines a method for a mobile device to obtain a map from one database, call up resource information such as the location of a hotel from a second database, and overlay the two sets of data.
Motorola and Microsoft are engaged in separate patent disputes in courts in Mannheim, Germany and Seattle over Motorola's use of scheduling software and Microsoft's use of some video and wireless technology.