For certain applications such as E911/E999/E112, GPS chipset receiver manufacturers will possibly have to test their products to ensure these fulfill mandated performance specifications for a variety of outdoor and indoor conditions. As opposed to testing in the field, laboratory testing is totally repeatable and controllable, and may be less costly. Hardware GPS signal simulators are now able to simulate signals under a variety of attenuation and multipath conditions. In indoor environments, GPS signals suffer not only from severe attenuation and multipath but from complex variations thereof. A method to simulate indoor GPS signals such that the stochastic characteristics of the simulated signals match those of actual GPS signals received in situ by a high sensitivity GPS receiver in various indoor environments is presented. Probability density functions and correlation coefficients are used to demonstrate the similarity between field and simulated data in terms of signal power fading and estimated pseudorange error. The results clearly demonstrate the feasibility of the approach.
