1. Field
The present disclosure relates generally to position estimation techniques and, more particularly, to logo detection for indoor positioning for use in or with mobile communication devices.
2. Information
Mobile communication devices, such as, for example, cellular telephones, portable navigation units, laptop computers, personal digital assistants, or the like are becoming more common every day. Certain mobile communication devices, such as, for example, location-aware cellular telephones, smart telephones, or the like may assist users in estimating their geographic locations by providing position information obtained or gathered from various systems. For example, in an outdoor environment, certain mobile communication devices may obtain a position estimate or so-called “position fix” by acquiring wireless signals from a satellite positioning system (SPS), such as the global positioning system (GPS) or other like Global Navigation Satellite System (GNSS), cellular base station, location beacon, or the like via a cellular telephone or other wireless communications network. In some instances, received wireless signals may be processed by or at a mobile communication device, and its location may be estimated using known techniques, such as, for example, Advanced Forward Link Trilateration (AFLT), base station identification, or the like.
In an indoor environment, at times, mobile communication devices may be unable to reliably receive or acquire satellite or like wireless signals to facilitate or support one or more position estimation techniques. For example, signals from an SPS or other wireless transmitters may be attenuated or otherwise affected in some manner (e.g., insufficient, weak, fragmentary, etc.), which may at least partially preclude their use for position estimations. As such, in an indoor environment, different techniques may be employed to enable navigation or location services. For example, a mobile communication device may obtain a position fix by measuring ranges to three or more terrestrial wireless access points positioned at known locations. Ranges may be measured, for example, by obtaining a Media Access Control identifier (MAC ID) address from wireless signals received from suitable access points and measuring one or more characteristics of received signals, such as signal strength, round trip delay, or the like. A position of a mobile communication device, such as in an indoor environment, for example, may also be estimated via heat map or radio map signature matching. For example, current or live characteristics of wireless signals received at a mobile communication device may be compared with expected or previously measured signal characteristics stored as heat map values in a database. By finding a signature in a database that more closely matches characteristics exhibited by signals currently received at a mobile communication device, a location associated with a matching signature may be used as an estimated location of the device.
In some instances, however, such as, for example, in larger indoor or like areas, relatively dense environments prone to multipath or fading effects (e.g., shopping malls, retailer outlets, etc.), or the like, access point or like wireless transmitter distribution may be less than sufficient or adequate for accurate or otherwise suitable positioning. In addition, at times, pre-measuring signal characteristics so as to construct a heat map for a particular indoor area of interest may be labor-intensive, time-consuming, costly, etc. Also, once constructed, heat maps tend to be rather static and, as such, may be difficult or expensive to update or reconstruct in a relatively dynamic environment associated with a corresponding physical location. Accordingly, how to improve or otherwise enhance position accuracy, such as in an indoor or like environment (e.g., urban canyons, etc.), for example, continues to be an area of development.