A method for improving geolocation accuracy in a passive radar warning receiver, using synchronized data curve-fit and interpolation to asynchronous and noisy receiver and navigation measurements over observation periods that are extended to reduce inaccuracies caused by noise. The present disclosure yields synchronized data samples at intervals short enough that constant-rate equations are valid, even though the actual motions over the observation interval may be more complex and have higher-order dynamics. It reduces noise, synchronizes data samples, and is readily adapted to motions with variable acceleration. The method generates rate samples short enough to satisfy constant rate assumptions, yet fit data over intervals long enough to enhances measurement accuracy by reducing measurement noise.

A method and apparatus related to developing electromagnetic emission and power models for a target device using photonic emissions thereof are provided. Data of photonic emissions of a target device during a first period of time with the target device in one or more modes is recorded. Data of electromagnetic emissions of the target device during the first period of time with the target device in the one or more modes is also recorded. The recorded data of the photonic emissions and the recorded data of the electromagnetic emissions are correlated to establish one or more electromagnetic emission models for the target device. The one or more electromagnetic emission models enable predictive analysis of emissions by the target device.

In accordance with an embodiment of the invention, a sound masking system is used to produce a sound masking zone in the vicinity of a defined area, for example in an area surrounding a conference room, an area within a medical office, or an area within a place of worship. A screen of loudspeakers around the defined area is used to create the sound masking zone. An indicator light, outside the defined area and unique to the sound masking zone around the defined area, is used to indicate that the sound masking system is active or ramping up.

Methods, systems, and apparatus, including computer programs encoded on storage devices, for drone-augmented emergency response services. In one aspect, a device includes a network interface, one or more sensors, one or more processors, and one or more storage devices that include instructions that are operable to perform operations. The operations include monitoring a predetermined geographic area that surrounds a particular property, determining that a drone device is within the predetermined geographic area that surrounds the particular property, determining whether the drone device that is detected within the predetermined geographic area that surrounds the property is an unauthorized drone device, and in response to determining that the drone device that is detected within the predetermined geographic area that surrounds the property is an unauthorized drone device, transmitting a signal indicating the detection of the unauthorized drone device within the predetermined geographic area that surrounds the property.

In some aspects, a wireless-signal source locator system includes wireless sensor devices distributed at distinct locations over a geographic region. The wireless sensor devices are configured to passively monitor wireless communication network signals in the geographic region. Each wireless sensor device is configured to receive a source signal wirelessly transmitted by a source (e.g., a mobile device, etc.) and a reference signal (e.g., from a synchronization source). The wireless sensor devices can generate arrival-time data based on the source signal and the reference signal. The wireless-signal source locator system further includes a data analysis system configured to receive the arrival-time data from the wireless sensor devices and to identify a location of the source based on analyzing the arrival-time data generated by three or more of the wireless sensor devices.

A remote antenna security system for preventing unauthorized reading of RFID cards. The RFID remote antenna security system generally includes at least one remote contact in communication with a remote antenna. A carrier member is provided that includes at least one contact and a tag that is in communication with the at least one contact. When the contact of the carrier member is physically connected to the remote contact of the remote unit, the radio waves received by the remote antenna are communicated to the tag and the tag transmits radio waves including data from the remote antenna for reading by the reader.

A method for improving geolocation accuracy in a passive radar warning receiver, using synchronized data curve-fit and interpolation to asynchronous and noisy receiver and navigation measurements over observation periods that are extended to reduce inaccuracies caused by noise. The present disclosure yields synchronized data samples at intervals short enough that constant-rate equations are valid, even though the actual motions over the observation interval may be more complex and have higher-order dynamics. It reduces noise, synchronizes data samples, and is readily adapted to motions with variable acceleration. The method generates rate samples short enough to satisfy constant rate assumptions, yet fit data over intervals long enough to enhances measurement accuracy by reducing measurement noise.

In some aspects, a wireless-signal source locator system includes wireless sensor devices distributed at distinct locations over a geographic region. The wireless sensor devices are configured to passively monitor wireless communication network signals in the geographic region. Each wireless sensor device is configured to receive a source signal wirelessly transmitted by a source (e.g., a mobile device, etc.) and a reference signal (e.g., from a synchronization source). The wireless sensor devices can generate arrival-time data based on the source signal and the reference signal. The wireless-signal source locator system further includes a data analysis system configured to receive the arrival-time data from the wireless sensor devices and to identify a location of the source based on analyzing the arrival-time data generated by three or more of the wireless sensor devices.