Determining a target's range profiles is an important issue for coastal surveillance radars because it can give us the knowledge about the target, for example, target's type, target's structure and its length along radial direction. Some modern radars nowaday are equipped with the feature of target's range profile extraction, but the results are not accurate due to limitations in processing algorithms. The invention “system and method of determining target's range profiles for coastal surveillance radars” solves the above problem in the direction of proposing a system of technical solutions and associated algorithm improvements.

Provided is method for determining free space surrounding a device, the method comprising: acquiring radar data regarding each of one or more radar antennas, the acquired radar data comprising range data and range rate data; extracting, from the acquired radar data, a specific set of radar data having values equal to or below a noise-based threshold; and determining a free space around the device based on the extracted specific set of radar data.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a wireless device may transmit a frequency-modulated continuous-waveform (FMCW) dual ramp radar signal over a time duration that sweeps from a first frequency to a second frequency and from the second frequency to the first frequency. The wireless device may receive a reflection of the radar signal with a first reflected part that corresponds to the first part of the radar signal and a second reflected part that corresponds to the second part of the radar signal. The wireless device may compare the first reflected part and a time-inverted version of the second reflected part to estimate a noise pattern. The wireless device may perform an action based at least in part on the noise pattern. Numerous other aspects are described.

A radar system may include a transmitter, a receiver, and a controller. The controller may calculate a received beam response spectrum based on the received reflected radar signal, detect a first maximum value of the received beam response spectrum, identify an angle corresponding to the first maximum value as a first target angle, obtain a threshold envelope based on the first maximum value and the first target angle, detect a second maximum value in a portion of the received beam response spectrum being greater than the threshold envelope, identify an angle corresponding to the second maximum value as a second target angle, and output the first target angle as the angle of arrival of the reflected radar signal from the first target and the second target angle as the angle of arrival of the reflected radar signal from the second target.

A vehicle radar system, apparatus and method use a radar control processing unit generate compressed radar data signals, to apply the compressed radar data signals to a log detector to generate log detector sample values, and to generate a first log cell-average constant false alarm rate (CA-CFAR) threshold from the log detector sample values by computing and adding an average sample value S.sub.AVG from the log detector sample values, a probability of false alarm factor α, and a log CA-CFAR correction factor β, where the first log CA-CFAR threshold may be used with a second log CA-CFAR threshold to generate an ordered statistics CA-CFAR threshold for the compressed radar data signals by sorting the first and second log CA-CFAR thresholds by magnitude to form a sorted list of log CA-CFAR thresholds, and then selecting a kth threshold from the sorted list of log CA-CFAR thresholds as the OS-CA-CFAR threshold.

A radar fill level measurement device for determining a fill level of a medium is provided, including a transmitter configured to transmit a transmission signal towards the medium; a receiver configured to receive a reception signal reflected by the medium; and a controller configured to determine the fill level of the medium based on the reception signal and based on at least one evaluation parameter, the radar fill level measurement device being configured to vary a transmitting power of the transmission signal, the controller being further configured to determine a current transmitting power of the transmission signal, and the controller being further configured to vary, based on the determined current transmitting power, a value of the at least one evaluation parameter and/or at least one measurement signal that correlates with the reception signal, such that the fill level is determined taking into account the transmitting power.

Techniques are described for determining a likelihood that a radar device failed to detect an object (i.e., a false negative). Determining the likelihood may be based at least in part on determining an estimated noise floor based at least in part on at least a portion of radar data, which may comprise one or more detections, and determining a likelihood that the portion of radar data includes a false positive, based at least in part on the estimated noise floor and a response profile associated with an object. A response profile may identify a received signal power and/or radar cross section associated with an object type.

A method for retrieval of lost radial velocity in weather radar includes expanding a radial velocity area to non-meteorological echoes including sea clutter and chaff echo using raw radar data for use of a wind field calculation area, correcting radial velocity by replacing the radial velocity determined as noise using a median sign comparison method with a median calculated within a window to which the radial velocity belongs, distinguishing a lost radial velocity area by comparing the corrected radial velocity with radar reflectivity data, and retrieving lost radial velocity using a Velocity Azimuth Display (VAD) fit function representing radial velocity of particles observed along a radar radiation source at a certain elevation in the lost radial velocity area as a function of an azimuth angle. Accordingly, it is possible to improve the quality of calculated wind field using the improved radar radial velocity, and provide more accurate dynamic structure information of the precipitation system.

Signal processing circuitry includes at least one processor configured to obtain a digitized radar signal, and further configured, for one or more iterations, to: determine a first power of at least one first signal sample of the radar signal; determine a second power of at least one second signal sample of the radar signal, the at least one second signal sample being subsequent in time to the at least one first signal sample; and determine a difference value between the second power and the first power. The at least one processor further configured to detecting a burst interference signal occurring within the radar signal based on the one or more difference values from the one or more iterations.

This document describes techniques and systems for asymmetrical frequency-division multiplexing (FDM) for radar systems. In some examples, a radar system includes multiple transmitters, multiple receivers, multiple polyphase shifters, and a processor. The transmitters can transmit electromagnetic (EM) signals in an FDM scheme. The receivers can receive EM signals reflected by one or more objects that include multiple channels. The polyphase shifters can introduce at least four potential phase shifts. The processor can control the polyphase shifters to introduce phase shifts asymmetrically spaced in a frequency spectrum. The processor can determine, using residue estimation and subtraction, potential detections of the objects. In this way, the described asymmetrical FDM for radar systems can support many simultaneous MIMO channels, increase the dynamic range of the radar system, resolve Doppler ambiguities, and provide an efficient processing scheme.