GNSS Receiver class. Instantiable, extendable, non-restrictable, non-substitutable. This class is used to include a given GNSS receiver in a proc input xml file. The only thing we're adding to the base class is the element "gnssReceiverConfig" with type "gnssReceiverConfigType" to access this complexType's firmware element. GNSS Antenna class. Instantiable, extendable, non-restrictable, non-substitutable. This class is used to include a given GNSS receiver in a proc input xml file. We're just extending gnssAntennaType so we can use it in an instance.