The test bed has two primary functions: firstly, it will have the capability to act as a mobile ‘truth' source which can be used to test the performance of other positioning sensors. An example of which may be that a user will use the test bed to investigate the performance a HSGPS receiver or other indoor positioning sensor. Secondly, the test bed will provide the capability for users to implement and test new sensors and algorithms by providing an open architecture design. For example, future developments in MEMS inertial sensors could be tested by removing the standard SPACE inertial sensor suite and replacing it with the MEMS technology. Similarly, users will be able to test their own algorithms through the open interface.