Globalstar differs from Iridium in two important ways. First, Globalstar satellites are simple bent pipe repeaters; there is no inter-satellite linking. Second, Globalstar orbits have an inclination of 52 degrees, compared to the near-polar 86.4 degree orbits used by Iridium_(satellite).
A network of ground gateway stations provides connectivity from the satellites to the public switched telephone network. Because there is no inter-satellite linking, a satellite must have a gateway station in view to provide service to any users it may see. Because no gateway stations cover certain remote areas (such as oceans far from land), no service can be provided in those areas even though the satellites fly over them.
Globalstar also does not cover polar areas due to the lower orbital inclination.
Despite (or because) of these limitations, Globalstar is significantly cheaper and can support somewhat higher data rates than Iridium. However, neither system has been a commercial success.
Globalstar is a joint venture of Qualcomm and Loral.