Various presence detection techniques are disclosed. In some embodiments, a system comprises a signal generator configured to generate a signal that includes a plurality of selected frequencies that are selected from among a set of candidate frequencies, wherein inclusion or exclusion of each candidate frequency in the signal encodes a bit of information and wherein the encoded information comprises a store identifier that identifies a retail store; and a transmitter configured to transmit the signal within the retail store; wherein presence of a device in the retail store is determined in response to reception of the signal at the device and extraction of the store identifier from the received signal by decoding the received signal.

A mobile computer may determine it is located in a vehicle or a conveyance based on a measured distance, satellite related positioning information, and a touch input.

Biometric monitoring devices, including various technologies that may be implemented in such devices, are discussed herein. Additionally, techniques, systems, and apparatuses are discussed herein for providing power-conserving techniques and systems for efficiently utilizing a GPS receiver are described. The positional fix frequency of the GPS receiver may, according to some implementations, be modified or adjusted between various levels according to data from one or more non-GPS sensors. Such non-GPS sensors may include, for example, ambient light intensity or spectrum sensors, accelerometers, gyroscopes, magnetometers, heart rate sensors, galvanic skin response sensors, infrared sensors, etc.

Systems and methods are provided for determining that the device is not reporting precise location information, based on output from one or more sensors determining that the device is located indoors and determining the altitude of the device. Based on the determination that the device is located indoors, suspending precise location services until it is determined that the device is back outdoors.

Systems and methods are provided for determining that the device is not reporting precise location information, based on output from one or more sensors determining that the device is located indoors and determining the altitude of the device. Based on the determination that the device is located indoors, suspending precise location services until it is determined that the device is back outdoors.

Calibrating an unstable sensor of a mobile device. Systems and methods for calibrating a sensor of a mobile device determine a first estimated position of the mobile device without using any measurement from the sensor of the mobile device, generate a second estimated position of the mobile device using a measurement from the sensor, estimate a sensor error of the sensor using the first estimated position and the second estimated position, and use the sensor error to determine a calibration value for adjusting one or more measurements from the sensor.

A system and method for recognizing features for location correction in Simultaneous Localization And Mapping operations, thus facilitating longer duration navigation, is provided. The system may detect features from magnetic, inertial, GPS, light sensors, and/or other sensors that can be associated with a location and recognized when revisited. Feature detection may be implemented on a generally portable tracking system, which may facilitate the use of higher sample rate data for more precise localization of features, improved tracking when network communications are unavailable, and improved ability of the tracking system to act as a smart standalone positioning system to provide rich input to higher level navigation algorithms/systems. The system may detect a transition from structured (such as indoors, in caves, etc.) to unstructured (such as outdoor) environments and from pedestrian motion to travel in a vehicle. The system may include an integrated self-tracking unit that can localize and self-correct such localizations.

In the vehicle communication system provided with the in-vehicle device for transmitting and receiving signals using the plurality of antennas, which are provided in different positions in the vehicle, and the portable device for transmitting and receiving the signals, the in-vehicle device: stores statistical values derived by measuring in advance received signal strengths of signals transmitted from a part of the plurality of antennas in associated with information identifying antennas of transmission sources, for each of the inside and the outside of a vehicle cabin of measured positions detects an antenna having a failure; calculates, for inside and outside the vehicle cabin, the statistical distance between the measured received signal strength and the statistical values corresponding to the selected antennas; makes a comparison between the results of the calculation; and determines whether the portable device is inside or outside the vehicle cabin.

The present disclosure provides a method for determining a real-time position of a mobile device using a global positioning system (GPS) and wireless local area network (WLAN) hybrid positioning mode. The method includes determining, by a mobile device, the mobile device's environment area based on GPS satellite signals; determining an absolute position of the mobile device based on the GPS satellite signals while the mobile device is moving from an outdoor area to an indoor area; estimating a reference position of the mobile device based on the determined absolute position and WLAN access point signals while moving to a shadow area; and while moving to an indoor area, determining an estimated position of the mobile device based on calculated regressive coefficients and the WLAN access point signals, and updating the estimated position of the mobile device based on motion information and indoor floor map information.

Embodiments disclosed aggregate a plurality of crowdsourced measurement sets for antennas received from a plurality of Mobile Stations (MS) with a Base Station Almanac (BSA), based on a measurement location estimate and a measurement location uncertainty estimate associated with each measurement set. A map comprising a plurality of map layers may be obtained, where each map layer associates locations in the BSA with spatially variable Forward Link Calibration (FLC) values for the antenna derived from the updated BSA data, wherein each spatially variable FLC value is associated with a corresponding location in the updated BSA data. Map layers, which may also include multipath map and/or received signal strength layers, may be provided to MS as location assistance data.