摘要:
In selected embodiments, a process of geolocation of a transmitter uses a receiver with an antenna array that is non-line-of-sight (NLoS) to the transmitter. A first plurality of scatterers within line-of-sight (LoS) of the array is located using multilateration based on time difference of arrival (TDoA) from the first scatterers, and applying a spatial consistency requirement. Time of emission/reflection from the first scatterers is also determined. The coordinates and timing of the first scatterers are used to locate either the transmitter or another set of scatterers, by applying multilateration to the TDoA at the first scatterers, and applying the spatial consistency requirement. The process is iteratively repeated until the transmitter is identified. The multilateration may be linearized without sacrificing precision. In each iteration, a non-singularity requirement is applied to ensure that the selected scatterers produce unambiguous results.
摘要:
Selected embodiments use a relatively small image detector and a scanning mirror to obtain effective performance of a larger image detector. An imager with folded optics captures images of different field positions of a field of view (FOV), and stitches the images together for a larger image of the FOV. The stitched image is processed to identify portions of interest within the larger image, for example, using a cuing algorithm. The portions of interest are scanned again to capture enhanced quality images using, for example, longer dwell time for enhanced contrast. Another image of the FOV or a part of the FOV is stitched together using the enhanced quality images.
摘要:
Selected described embodiments include an imager providing concurrent wide field of view (WFOV) and foveated images. The imager includes a frontend optic configured to receive light from a scene. Corrective optics reduces distortions, and transmits the light to a beam splitter. One portion of the light exiting the beam splitter is focused on a WFOV image detector. A second portion of the light falls on a scanning mirror that can be configured to target a selected field position in the field of view. From the scanning mirror, the light passes through a magnifier and is corrected by an adaptive wavefront corrector. The corrector may be configured to correct aberrations corresponding to the particular field of view selected by the scanning mirror. The light from the wavefront corrector is focused on a foveated image detector. The images captured by the image detectors may be stored, processed, and transmitted to other systems.
摘要:
In selected embodiments, improved image restoration is realized using extensions of Wiener filtering combined with multiple image captures acquired after simple, fast reconfigurations of an optical imaging system. These reconfigurations may yield distinct OTF responses for each capture. The optical imaging system may reduce fabrication cost, power consumption, and/or system weight/volume by correcting significant optical aberrations. The system may be configured to perform independent correction of fields within the total field-of-regard. The system may also be configured to perform independent correction of different spectral bands.
摘要:
Techniques, apparatuses and systems for providing communications based on time reversal of a channel impulse response of a pulse in a transmission channel between a transmitter and a receiver to enhance reception and detection of a pulse at the receiver against various effects that can adversely affect and complicate the reception and detection of the pulse at the receiver.
摘要:
Dynamic, untethered array nodes are frequency, phase, and time aligned/synchronized, and used to focus their transmissions of the same data coherently on a target or in the target's direction, using time reversal or directional beamforming. Information for alignment/synchronization may be sent from a master node of the array to other nodes, over non-RF links, such as optical and acoustic links. Some nodes may be connected directly to the master nodes, while other nodes may be connected to the master node through one or more transit nodes. A transit nodes may operate to (2) terminate the link when the alignment/synchronization information is intended for the node, and (2) pass through the alignment/synchronization information to another node without imposing its local clock properties on the passed through alignment/synchronization information. In this way, an end point node may be aligned/synchronized to the master node without a direct link between the two nodes.
摘要:
Dynamic, untethered array nodes are frequency, phase, and time aligned, and used to focus their transmissions of the same data coherently on a target, using time reversal. Alignment may be achieved separately for the radio frequency (RF) carriers and the data envelopes. Carrier alignment may be by phase conjugation. The data is distributed across the nodes. Data distribution and/or alignment may be performed by a Master node of the array. The nodes capture a sounding signal from the target, in the same time window. Each node converts the captured sounding signal to baseband, for example, using in-phase/quadrature downconversion. Each node stores the baseband samples of the sounding pulse. Each node convolves time-reversed samples of the sounding signal with the data, and upconverts the convolved data to radio frequency. The nodes emit their respective convolved and upconverted data so that the emissions focus coherently at the target.
摘要:
Techniques, apparatus and systems for providing radio frequency wireless communications based on time reversal of the channel impulse response of an RF pulse in a transmission channel between an RF transmitter and an RF receiver to enhance reception and detection of an RF pulse at the RF receiver against various effects that can adversely affect and complicate the reception and detection of the RF pulse at the RF receiver.
摘要:
Techniques, apparatuses and systems for providing communications based on time reversal of a channel impulse response of a pulse in a transmission channel between a transmitter and a receiver to enhance reception and detection of a pulse at the receiver against various effects that can adversely affect and complicate the reception and detection of the pulse at the receiver.
摘要:
Techniques, apparatuses and systems for providing communications based on time reversal of a channel impulse response of a pulse in a transmission channel between a transmitter and a receiver to enhance reception and detection of a pulse at the receiver against various effects that can adversely affect and complicate the reception and detection of the pulse at the receiver.