Abstract: To reduce power consumption in a user terminal, especially mobile devices, a system and method are introduced that use terrestrial beacons as a location proxy when satellite positioning signals are not available. The geographic locations of the terrestrial beacons need not be known to use the beacons as a proxy for a satellite positioning signals derived location.

Abstract: Modern cellular wireless communications providers strive to keep their network and subscribers secure through various means. The identity of the subscriber may be obfuscated through the use of a temporary identifier for most network transactions including signaling events, voice calls, SMS messages and data sessions. A subscriber's unique identity may only be transmitted over the air in an encrypted form. Similarly, the content of voice calls, SMS messages and data sessions may also be encrypted when transmitted over the air and even when transferred over internal network interfaces. However, the use of encryption presents significant challenges for law enforcement communities when court ordered lawful intercept is required to monitor and locate subscribers utilizing the wireless networks for illegal and/or terrorist purposes. A technique to aid in the determination of a subscriber's unique wireless identity and the decryption of encrypted signals would be very useful for lawful intercept.

Abstract: By combining imaging systems with wireless location functionality, a subject's videometric signature can be linked to a public identity, thus enabling continuous surveillance outside or between the coverage area of video surveillance networks. In addition to extending the surveillance coverage area, the combination of computerized video surveillance with wireless location determination may also allow for identification of mobile device users via the existing mobile equipment and user identifiers used in the wireless network.

Abstract: A method for improving the results of radio location systems that incorporate weighted least squares optimization generalizes the weighted least squares method by using maximum a posteriori (MAP) probability metrics to incorporate characteristics of the specific positioning problem (e.g., UTDOA). Weighted least squares methods are typically used by TDOA and related location systems including TDOA/AOA and TDOA/GPS hybrid systems. The incorporated characteristics include empirical information about TDOA errors and the probability distribution of the mobile position relative to other network elements. A technique is provided for modeling the TDOA error distribution and the a priori mobile position. A method for computing a MAP decision metric is provided using the new probability distribution models. Testing with field data shows that this method yields significant improvement over existing weighted least squares methods.

Abstract: A method and system for enhancing the accuracy and robustness of locations determined for a mobile wireless transceiver in a cellular telephone communications system integrating location-related information both from an assisted GPS device embedded in the mobile unit and from infrastructure-based facilities that extract signal characteristic data at networked base stations. Available supporting collateral information may be additionally evaluated in the location determinations to provide location estimates of enhanced robustness and accuracy.

Abstract: In a network-based Wireless Location System (WLS), geographically distributed Location Measurement Units (LMUs) must be able to detect and use reverse channel (mobile to network) signals across multiple BTS coverage areas. By using Matched Replica correlation processing with the local and reference signals subdivided into discrete segments prior to correlation, the effects of mobile clock drift and Doppler shifts can be mitigated allowing for increased processing gain.

Abstract: Techniques for locating wireless devices involve a wireless device making measurements of signals transmitted by geographically distributed base stations within a wireless network. If some key site information is known about these transmitters, such as the transmitter location, transmit signal power, signal propagation, and transmit signal timing, measurements of these transmit signals by a device to be located can be used to determine the position of the device. In this example, all information exchange between the device and the location node is facilitated by a data link that is not provided by the wireless network providing signals used in the location estimation process.

Abstract: One illustrative embodiment takes the form of a system for locating wireless transmitters employing an Orthogonal Frequency Division Multiplexing (OFDM) digital modulation scheme. The OFDM scheme comprises transmitting signal components over narrowband frequency channels spanning a wideband channel. The system includes a first receiving system configured to receive a fraction of the signal components transmitted by a first wireless transmitter to be located in a fraction of the narrowband frequency channels, and to process the fraction of the signal components to derive location related measurements. The system further includes at least a second receiving system configured to receive the fraction of the signal components transmitted by the first wireless transmitter, and to process this fraction of the signal components to derive location related measurements.

Abstract: A wireless location system may include geolocation of a wireless device connected to Voice-over-Internet-Protocol (VoIP) adapter. The VoIP adapter may include a wireless transceiver or a wireless location determining receiver that facilitates the location of a wireless device connected to the VoIP adapter. The wireless transceiver or the location determining receiver may provide location information to an emergency dispatcher.

Abstract: Several techniques for locating wireless devices involve the Mobile Stations (MS) making measurements of the signals transmitted by geographically distributed base stations within a wireless network. If some key site information is known about these transmitters, such as the transmitter location, transmit signal power, signal propagation, and transmit signal timing, measurements of these transmit signals by a MS can be used to determine the position of the MS. An automatic method to detect transmitters, identify key transmitter information, and utilize the base station transmit signals to perform location is presented. In addition, this method facilitates the use of cell site transmit signals that are part of multiple wireless networks.

Abstract: One illustrative embodiment takes the form of a system for locating wireless transmitters employing an Orthogonal Frequency Division Multiplexing (OFDM) digital modulation scheme. The OFDM scheme comprises transmitting signal components over narrowband frequency channels spanning a wideband channel. The system includes a first receiving system configured to receive a fraction of the signal components transmitted by a first wireless transmitter to be located in a fraction of the narrowband frequency channels, and to process the fraction of the signal components to derive location related measurements. The system further includes at least a second receiving system configured to receive the fraction of the signal components transmitted by the first wireless transmitter, and to process this fraction of the signal components to derive location related measurements.

Abstract: A Network Autonomous Wireless Location System (NAWLS) is designed to allow for precise location of a mobile device (e.g., a cell phone) without interconnection to, and with minimal disruption of, the local wireless communications network. Using distributed radio network monitors (RNM) and a managed network emulator (NE); mobile devices are sampled, acquired or captured. Once triggered by the RNM or NE, an untethered wireless location system (U-WLS) is used to calculate a precise location. The U-WLS; comprising mobile receiver sites, each capable of self location, exchanging information with other components of the NAWLS, and receiving or exchanging signals from the mobile device; utilizes various network-based and handset-based wireless location techniques dependent on the deployed options. In addition, the NAWLS includes data links interconnecting the U-WLS, NE and RNM.

Abstract: Iterative geolocation of a stationary RF emitter through the use of TDOA may include the use of a single portable geolocation (e.g., TDOA) sensor, a pair of portable geolocation sensors and three of more portable geolocation sensors. Adding portable geolocation sensors to the iterative process reduces the constraints on the signals to be located as well as providing a reduction in the number of iterations required to obtain improved location accuracy.

Abstract: Several techniques for locating wireless devices involve the Mobile Stations (MS) making measurements of the signals transmitted by geographically distributed base stations within a wireless network. If some key site information is known about these transmitters, such as the transmitter location, transmit signal power, signal propagation, and transmit signal timing, measurements of these transmit signals by a MS can be used to determine the position of the MS. An automatic method to detect transmitters, identify key transmitter information, and utilize the base station transmit signals to perform location is presented. In addition, this method facilitates the use of cell site transmit signals that are part of multiple wireless networks.

Abstract: Methods and systems are employed by a wireless location system (WLS) for locating a wireless device operating in a geographic area served by a wireless communications system. An exemplary method includes monitoring a set of signaling links of the wireless communications system, and detecting at least one predefined signaling transaction occurring on at least one of the predefined signaling links. Then, in response to the detection of the at least one predefined network transaction, at least one predefined location service is triggered.

Abstract: A mobile wireless device is configured to provide a location quality of service indicator (QoSI) indicative of the quality of a calculated location estimation for use by a location-based service. The QoSI may be calculated by the device itself or by a server, such as a location enabling server (LES). The QoSI may be used to represent the predicted location accuracy, availability, latency, precision, and/or yield.

Abstract: Method and systems are employed by a wireless location system (WLS) for locating a wireless device operating in a geographic area served by a wireless communications system. An exemplary method includes monitoring a set of signaling links of the wireless communications system, and detecting at least one predefined signaling transaction occurring on at least one of the predefined signaling links. Then, in response to the detection of the at least one predefined network transaction, at least one predefined location service is triggered.

Abstract: Disclosed are methods and systems for filtering an intermediate frequency (IF) band when digitizing a radio frequency (RF) signal using a higher Nyquist zone several times above the sampling rate. Undersampling may be employed along with an undersampled Nyquist filtering technique to implement an integrated receiver for base station applications such as wireless base station beacon monitoring. Such a receiver may be integrated into a smaller package and consume less power at a reduced cost. In one embodiment, the receiver may operate at a high RF sampled frequency that is microsampled in the 10th Nyquist zone at less than 20% undersampling. In another embodiment, the receiver may operate in the 5th Nyquist zone at ½ the sampling rate with 40% undersampling. In various embodiments, sampling and processing functions may be implemented using software on a computer or other embedded computing device.

Abstract: A method for improving the results of radio location systems that incorporate weighted least squares optimization generalizes the weighted least squares method by using maximum a posteriori (MAP) probability metrics to incorporate characteristics of the specific positioning problem (e.g., UTDOA). Weighted least squares methods are typically used by TDOA and related location systems including TDOA/AOA and TDOA/GPS hybrid systems. The incorporated characteristics include empirical information about TDOA errors and the probability distribution of the mobile position relative to other network elements. A technique is provided for modeling the TDOA error distribution and the a priori mobile position. A method for computing a MAP decision metric is provided using the new probability distribution models. Testing with field data shows that this method yields significant improvement over existing weighted least squares methods.

Abstract: An Applications Processor (14) including a centralized database system is used in a wireless location system (WLS). The APs 14 may be used to manage resources in the WLS, including signal collection systems (SCSs 10) and TDOA location processors (TLPs 12). Each AP 14 contains a database containing triggers for the WLS. The WLS can be programmed to locate only certain pre-determined types of transmissions. When a transmission of a pre-determined type occurs, then the WLS is triggered to begin location processing. Each AP 14 also contains applications interfaces that permit a variety of applications to securely access the WLS. These applications may access location records in real time or non-real time, create or delete certain types of triggers, or cause the WLS to take other actions. Each AP 14 is also capable of certain post-processing functions.