Abstract: A method is described which includes receiving a time series of radio data (S1). The method includes, for each of a plurality of buffer periods, at the end of a most recently elapsed buffer period, analysing the radio data of that buffer period to detect signals (S2). The method also includes, in response to detecting one or more signals ending within that buffer period (S4|Yes), determining a start time and an end time of that signal, and one or more signal properties corresponding to that signal, the signal properties including at least a duration, and storing (S5) that signal to a detailed database (DD) and a summary database (SD). Methods of querying the summary database (SD) and detailed database (AD) are also described, along with apparatuses for carrying out the methods.

Abstract: A method is described which includes receiving or obtaining a time series of data (S1). The method also includes storing the time series of data to a storage device without interrupting the reception of the time series of data (S2). The method also includes, for each of a plurality of base time periods, at the end of a most recently elapsed base time period (S5) and without interrupting the reception or storage of the time series of data, calculating (S6) one or more measurements based on the time series of data corresponding to the most recently elapsed base time period and updating a binary tree structure indexing the one or more measurements and the time series of data. Updating the binary tree structure includes generating a new binary tree leaf (1, 2, 4, 5) corresponding to the most recently elapsed base time period (S7).

Abstract: A frequency discriminator is described. The frequency discriminator comprises a power splitter (2) for splitting a signal into a plurality of paths (40, 41, 42, . . . , 4n). At least two of the plurality of paths (41, 42, . . . , 4n) include respective filters (121; 122, . . . , 12n) having different frequency characteristics which are configured to provide respective filtered signals to respective power detectors (161, 162, . . . , 16n. The frequency discriminator comprises an analogue-to-digital conversion section (8) which is configured to receive values of measured powers from the power detectors, to generate digital values of measured powers and to provide the digital values of measured powers to a digital processing section (10). The digital processing section is configured to estimate a value (11) of at least one frequency in the signal in dependence on the digital values, for example the ratio of the digital values, of measured powers and on frequency responses (201, 202, . . . , 20n; FIG.

Abstract: A method of determining incident angles of Radio Frequency, RF, signals received by an antenna array comprising a plurality of antennae is described. The method comprises generating a plurality of direction finding, DF, signals based on antenna signals received from the antenna array, wherein each DF signal corresponds to a respective antenna array element and each antenna array element corresponds to one or more antennae. A plurality of DF spectra are then generated, each DF spectrum corresponding to a respective DF signal and comprising measured values of signal power at two or more given respective frequencies. An incident signal angle is calculated for each given frequency, based on the measured values of power at the frequency, the configuration of the antennae in the antenna array and antenna gain patterns corresponding to the antenna array elements.

Abstract: A method for processing a primary data record, a spatial tree index and a plurality of time tree indexes is described. The method includes writing the primary data record to a primary data table, determining whether a spatial tree leaf node including location data exists and, if not, generating a spatial tree leaf node including the location data, and creating or updating spatial tree nodes connecting the spatial tree leaf node to a spatial tree root node. For spatial tree nodes including the location data, updating a respective time tree index by determining whether a time tree leaf node including time data exists and, if not, generating a time tree leaf node including the time data, and creating or updating time tree nodes connecting the time tree leaf node to a time tree root node. The time tree leaf node updated to include a pointer to the primary data record.

Abstract: Apparatus for generating an RF signal for use in RF signal detection is described. The apparatus comprises at least one processor configured to generate a set of IQ data based on at least one set of weighted IQ data, each set of weighted IQ data having a respective weight and a circuit configured to generate an RF signal using the set of IQ data. The at least one processor is configured to calculate each respective weight in dependence upon location of a signal detector or an antenna associated with the RF signal detector.

Abstract: A frequency discriminator comprising a power splitter for splitting a signal into first and second paths, wherein the first path is configured to provide a first, straight-through signal and the second path includes a frequency-dependent element, such as low-pass filter, so as to provide a second signal. The frequency discriminator further comprises a circuit configured to compare the first and second signals and generate an instantaneous frequency signal in dependence thereon.

Abstract: Apparatus for generating an RF signal for use in RF signal detection is described. The apparatus comprises at least one processor configured to generate a set of IQ data based on at least one set of weighted IQ data, each set of weighted IQ data having a respective weight and a circuit configured to generate an RF signal using the set of IQ data.

Abstract: A frequency discriminator comprising a power splitter for splitting a signal into first and second paths, wherein the first path is configured to provide a first, straight-through signal and the second path includes a frequency-dependent element, such as low-pass filter, so as to provide a second signal. The frequency discriminator further comprises a circuit configured to compare the first and second signals and generate an instantaneous frequency signal in dependence thereon.

Abstract: Apparatus for generating an RF signal for use in RF signal detection is described. The apparatus comprises at least one processor configured to generate a set of IQ data based on at least one set of weighted IQ data, each set of weighted IQ data having a respective weight and a circuit configured to generate an RF signal using the set of IQ data.