A signal processing unit performs, on the basis of a received electric field signal from an antenna by which a beam is scanned within a predetermined azimuthal angle and a signal of an azimuthal angle of the scanned beam, a Fourier transform on a distribution function of the received electric field signal into a frequency domain of the azimuthal angle, divides a signal according to a first spectral function by a signal according to a second spectral function, the first spectral function being obtained by performing the Fourier transform, the second spectral function being obtained by performing a Fourier transform on an antenna pattern of the antenna into a frequency domain of the azimuthal angle, and subjects the divided signal to fitting by using Prony's method with exponential functions including real parts and imaginary parts in arguments.

A signal processing unit performs, on the basis of a received electric field signal from an antenna by which a beam is scanned within a predetermined azimuthal angle and a signal of an azimuthal angle of the scanned beam, a Fourier transform on a distribution function of the received electric field signal into a frequency domain of the azimuthal angle, divides a signal according to a first spectral function by a signal according to a second spectral function, the first spectral function being obtained by performing the Fourier transform, the second spectral function being obtained by performing a Fourier transform on an antenna pattern of the antenna into a frequency domain of the azimuthal angle, and subjects the divided signal to fitting by using Prony's method with exponential functions including real parts and imaginary parts in arguments.

[Object] To provide an observation apparatus, an observation method, and a program that are capable of directly obtaining radio wave source information by using a deconvolution method and Prony's method, without using the phase of an electric field signal received by an antenna.

[Solving Means] An observation apparatus 10 includes a signal processing unit 15 that performs, using a square root signal of a received electric power signal from an antenna whose beam is scanned within a predetermined azimuthal angle range and a signal of an azimuthal angle of the scanned beam, a Fourier transform with respect to the azimuthal angle on the square root signal, divides a first azimuth frequency signal by a second azimuth frequency signal, the first azimuth frequency signal being obtained by performing the Fourier transform, the second azimuth frequency signal being obtained by performing a Fourier transform with respect to the azimuthal angle on a square root signal of an antenna electric power pattern or an antenna electric field pattern signal of the antenna, and fits the divided signal with exponential functions including real parts and imaginary parts in arguments by using Prony's method.

A measurement system for identifying a source direction of a wireless electromagnetic emitter signal is described. The measurement system is a radio frequency measurement system that comprises a rotary antenna and an analyzer or analysis unit being connected to the rotary antenna in a signal transmitting manner. The rotary antenna is a directional antenna and configured to receive the emitter signal and to forward the received emitter signal to the analysis unit for further processing. The measurement system is configured to gather a momentary position of the rotary antenna. The analysis unit is configured to determine a momentary frequency spectrum of the emitter signal and to combine the momentary frequency spectrum with the momentary position to generate source direction data comprising information on both the momentary frequency spectrum of the emitter signal and the momentary position of the rotary antenna. Moreover, a method for identifying a source direction of a wireless electromagnetic emitter signal is described.

A measurement system for identifying a source direction of a wireless electromagnetic emitter signal is described. The measurement system is a radio frequency measurement system that comprises a rotary antenna and an analyzer or analysis unit being connected to the rotary antenna in a signal transmitting manner. The rotary antenna is a directional antenna and configured to receive the emitter signal and to forward the received emitter signal to the analysis unit for further processing. The measurement system is configured to gather a momentary position of the rotary antenna. The analysis unit is configured to determine a momentary frequency spectrum of the emitter signal and to combine the momentary frequency spectrum with the momentary position to generate source direction data comprising information on both the momentary frequency spectrum of the emitter signal and the momentary position of the rotary antenna. Moreover, a method for identifying a source direction of a wireless electromagnetic emitter signal is described.

Using a phase interferometry method which utilizes both amplitude and phase allows the determination and estimation of multipath signals. To determine the location of an object, a signal that contains sufficient information to allow determination of both amplitude and phase, like a packet that includes a sinewave portion, is provided from a master device. A slave device measures the phase and amplitude of the received packet and returns this information to the master device. The slave device returns a packet to the master that contains a similar sinewave portion to allow the master device to determine the phase and amplitude of the received signals. Based on the two sets of amplitude and phase of the RF signals, the master device utilizes a fast Fourier transform or techniques like multiple signal classification to determine the indicated distance for each path and thus more accurately determines a location of the slave device.

Using a phase interferometry method which utilizes both amplitude and phase allows the determination and estimation of multipath signals. To determine the location of an object, a signal that contains sufficient information to allow determination of both amplitude and phase, like a packet that includes a sinewave portion, is provided from a master device. A slave device measures the phase and amplitude of the received packet and returns this information to the master device. The slave device returns a packet to the master that contains a similar sinewave portion to allow the master device to determine the phase and amplitude of the received signals. Based on the two sets of amplitude and phase of the RF signals, the master device utilizes a fast Fourier transform or techniques like multiple signal classification to determine the indicated distance for each path and thus more accurately determines a location of the slave device.

[Object] To enable to extract actual radio wave sources such that the actual radio wave source can be distinguished from information which is not the actual radio wave source even if the signal-to-noise ratio is not sufficiently high in radar observation and the like.

[Solving Means] The signal processing unit 15 performs, on the basis of a received electric field signal from an antenna by which a beam is scanned within a predetermined azimuthal angle and a signal of an azimuthal angle of the scanned beam, a Fourier transform on a distribution function of the received electric field signal into a frequency domain of the azimuthal angle, divides a signal according to a first spectral function by a signal according to a second spectral function, the first spectral function being obtained by performing the Fourier transform, the second spectral function being obtained by performing a Fourier transform on an antenna pattern of the antenna into a frequency domain of the azimuthal angle, and subjects the divided signal to fitting by using Prony's method with an exponential function including a real part and an imaginary part in an argument.

[Object] To enable to extract actual radio wave sources such that the actual radio wave source can be distinguished from information which is not the actual radio wave source even if the signal-to-noise ratio is not sufficiently high in radar observation and the like.

[Solving Means] The signal processing unit 15 performs, on the basis of a received electric field signal from an antenna by which a beam is scanned within a predetermined azimuthal angle and a signal of an azimuthal angle of the scanned beam, a Fourier transform on a distribution function of the received electric field signal into a frequency domain of the azimuthal angle, divides a signal according to a first spectral function by a signal according to a second spectral function, the first spectral function being obtained by performing the Fourier transform, the second spectral function being obtained by performing a Fourier transform on an antenna pattern of the antenna into a frequency domain of the azimuthal angle, and subjects the divided signal to fitting by using Prony's method with an exponential function including a real part and an imaginary part in an argument.

Using a phase interferometry method which utilizes both amplitude and phase allows the determination and estimation of multipath signals. To determine the location of an object, a signal that contains sufficient information to allow determination of both amplitude and phase, like a packet that includes a sinewave portion, is provided from a master device. A slave device measures the phase and amplitude of the received packet and returns this information to the master device. The slave device returns a packet to the master that contains a similar sinewave portion to allow the master device to determine the phase and amplitude of the received signals. Based on the two sets of amplitude and phase of the RF signals, the master device utilizes a fast Fourier transform or techniques like multiple signal classification to determine the indicated distance for each path and thus more accurately determines a location of the slave device.