A method for use in acoustic imaging, comprising: transmitting, from a transmitter, a first sound wave pulse at a first frequency determined by a maximum sampling rate of a receiver; transmitting at least one second sound wave pulse at a frequency substantially equal to the first frequency, the first and at least one second sound wave pulses being transmitted substantially within a fraction of a sample interval of the receiver; receiving and sampling, at the receiver, a reflection of at least two of the first and at least one second pulses to generate a set of receiver samples; and expanding the set of receiver samples, based on the first frequency and a total number of the first and at least one second pulses transmitted, to generate an expanded sample set with a larger number of samples than the set of receiver samples.

In some implementations, a non-terrestrial network (NTN) platform may transmit radio frequency (RF) signals toward earth, the RF signals comprising an orthogonal frequency-division multiplexing (OFDM) waveform with a plurality of symbols including a JCS symbol and one or more non-JCS symbols, wherein: the RF signals are incident on an area of the earth defining a footprint, and a duration of a cyclic prefix (CP) of the JCS symbol is a function of a width of the footprint. The NTN platform may receive, at the NTN platform, one or more reflections of the JCS symbol.

A system includes an analog front-end configured to process a signal to obtain amplified beams, the signal being formed by pulses of a plurality of beams, pulses of each of the plurality of beams being generated according to a time-hopping modulation scheme, a plurality of radars coupled to the analog front-end, the plurality of radars configured to transmit each of the amplified beams at a different angle, and to receive reflections of the transmitted beams, and a plurality of correlators coupled to the plurality of radars through the analog front-end, the plurality of correlators being configured to process the reflections of the transmitted beams to obtain proximity measurements.

The solid-state radar device includes: a transmission/reception unit configured to transmitting and receiving radio wave signals comprising a modulated signal and a non-modulated signal, which are pulse signals whose frequencies are different from each other; a frequency filter unit configured respectively to extract the modulated signal and the non-modulated signal from the received radio wave signals based on the frequencies; a pulse compression unit generating a pulse-compressed signal by pulse-compressing the modulated signal; a first echo image generation unit configured to generate a first echo image based on the non-modulated signal and the pulse-compressed signal; a wave analysis unit configured to analyze ocean wave information based on one of the non-modulated signal and the pulse-compressed signal; and a display signal generation unit configured to generate a display signal comprising the first echo image and/or the ocean wave information.

Various examples are provided related to penetrating radar based upon precursors. In one example, a method includes transmitting a radio frequency (RF) signal; and receiving a return signal associated with the RF signal, where the return signal is a precursor having no exponential decay. The precursor can be one of a sequence of precursors, which can be used to improve resolution of the system. The RF signal can be a short pulse generated by an RF front end, without automatic level control. The return signal can be processed without filtering.

Operating a stepped frequency radar system involves performing stepped frequency scanning across a frequency range using at least one transmit antenna and a two-dimensional array of receive antennas and using frequency steps of a fixed step size, processing a first portion of digital data that is generated from the stepped frequency scanning to produce a first digital output, wherein the first portion of the digital data is derived from frequency pulses that are separated by a first step size that is a multiple of the fixed step size, and processing a second portion of digital data that is generated from the stepped frequency scanning to produce a second digital output, wherein the second portion of the digital data is derived from frequency pulses that are separated by a second step size that is a multiple of the fixed step size, wherein the first multiple is different from the second multiple.

According to a first aspect, a pulsed radar comprises a transmitter; wherein the pulsed radar is arranged to generate a string of binary values; wherein the transmitter comprises a pulse generator arranged to generate a pulse signal comprising a series of transmit pulses with polarities determined in accordance with the string of binary values; wherein a first substring comprises a first series of values; wherein a second substring comprises a second series of values; wherein the second substring is different from the first substring; and wherein each value in the second series of values is either the same as or different from the corresponding value in the first series of values according to a repeating pattern; and wherein the string of binary values comprises at least the first substring and the second substring concatenated together and each optionally being reversed before concatenation.

A Time Domain Return measurement system for measuring liquid level, linear movement or other measurements which includes a first and second electrode, the second electrode spaced from the first electrode to define a gap, and an electronics assembly connected to the first and second electrodes equipped with a generator for transmitting an electromagnetic signal for propagation along the electrodes. The signal generator has a first analog timing circuit for actuating a slow-rising function of voltage versus time, a second analog timing circuit associated with the first analog timing circuit for actuating a fast-rising function of voltage versus time, and a receive circuit electrically connected to the electrodes, the receive circuit being activated for receiving return echo data associated with the electromagnetic signal transmitted when the fast-rising function is equal or greater than the slow-rising function to determine the position of the second medium with respect to the electrodes.

A Time Domain Return measurement system for measuring liquid level, linear movement or other measurements which includes a first and second electrode, the second electrode spaced from the first electrode to define a gap, and an electronics assembly connected to the first and second electrodes equipped with a generator for transmitting an electromagnetic signal for propagation along the electrodes. The signal generator has a first analog timing circuit for actuating a slow-rising function of voltage versus time, a second analog timing circuit associated with the first analog timing circuit for actuating a fast-rising function of voltage versus time, and a receive circuit electrically connected to the electrodes, the receive circuit being activated for receiving return echo data associated with the electromagnetic signal transmitted when the fast-rising function is equal or greater than the slow-rising function to determine the position of the second medium with respect to the electrodes.

A dual-polarization radar is disclosed. Selected embodiments provide a radar structure having a single receiving channel and enabling alternate transmission and simultaneous reception. Selected embodiments use a first polarization direction antenna and a second polarization direction antenna to transmit and receive a first polarization direction echo signal and a second polarization direction echo signal. The first polarization direction echo signal and the second polarization direction echo signal are received and synthesized by a synthesis module, which transmits the synthesized signal as the backscattered echo signal to a receiving module.