This paper proposes a RSSI of geomagnetic field-based indoor positioning method that takes advantage of the dependence of RSSI of geomagnetic field on the type of building material. Buildings are usually constructed with H-beam or reinforced concrete. However, most researches on RSSI of geomagnetic field-based indoor positioning do not consider the extent of geomagnetic field disturbance by building material. Based on the finding that RSSI of geomagnetic field is more affected by H-beam building than reinforced concrete building, and by applying interpolation, the proposed positioning method achieved efficient database generation. Experiments demonstrated that the proposed method not only efficiently reduced DB generation costs but also was faster.

Methods for addressing two types of multiplicative noise in synthetic aperture radar (SAR) imaging are presented. The authors consider a multiplicative noise with a real phase (i.e. the SAR signal's phase is contaminated but its amplitude is uncorrupted) that possesses unknown functional characteristics with respect to the radar signal's temporal frequencies. A perturbation solution for phase reconstruction from amplitude is developed from a wave equation governing the SAR signal and a Riccati equation that relates the amplitude and phase functions of the SAR signal. This solution is converted into a noniterative analytical solution in terms of the moments and powers of the log amplitude function. Next, the authors consider a multiplicative noise with a complex phase (i.e. both the amplitude and phase of the SAR signal are contaminated) that varies linearly with respect to the radar signal's temporal frequencies. The two wave equations governing the SAR signal at two temporal frequencies of the radar signal are combined to derive a method to reconstruct the complex phase error function.