Asked by: Brandon Chaplin
What causes range ambiguity?
Range aliasing occurs when reflections arrive from distances that exceed the distance between transmit pulses at a specific pulse repetition frequency (PRF). Range ambiguity resolution is required to obtain the true range when the measurements are made using a system where the following inequality is true.
What is range ambiguity in ultrasound?
Range-ambiguity artifacts (RAAs) are an erroneous mapping of returning echoes into a composite picture. The purpose of this review was to illustrate the mechanism of RAAs and to present the diagnostic problems caused by RAAs. RAA features differ slightly from organ to organ.
What are radar ambiguities?
A pulse Doppler radar can be ambiguous in either range or Doppler frequency. The ambiguity of a radar depends on the selected pulse repetition frequency (PRF). Three modes of airborne radar operation are well known: the high PRF (HPRF), medium PRF (MPRF), and low PRF (LPRF) mode.
What is ambiguity resolution in GNSS?
GNSS ambiguity resolution. The process of estimating the integer parameters of a mixed-integer model, based on their real-valued estimates and associated variance-covariance matrix. GNSS ambiguity validation. Applying an acceptance test to decide whether or not the estimated integer ambiguities are reliable enough.
How do you fix range ambiguity?
Range ambiguities are resolved at the lowest elevation angles by using additional antenna scans with relatively long pulse repetition times (PRTS). At middle elevation angles, batches of long-PRT transmitted pulses are alternated with batches of shorter PRT.
What is blind speed in radar?
The blind speed is a radial speed of the airplane at which the phase shifting of the echo-signal has the value ±n · 360° between two pulse periods. With blind speeds moving targets are suppressed by a MTI system like ground clutters.
What is range aliasing?
(Also called range folding.) In radar meteorology, a sampling problem that arises when echoes located beyond the maximum unambiguous range (rmax) are received as if they were within this range of the radar.
What is range resolution in ultrasound?
The range spatial resolution is an important factor determining the image quality in ultrasonic imaging. The range spatial resolution in ultrasonic imaging depends on the ultrasonic pulse length, which is determined by the mechanical response of the piezoelectric element in an ultrasonic probe.
How does CW radar work?
The Radar, which operates with continuous signal (wave) for detecting non-stationary targets, is called Continuous Wave Radar or simply CW Radar. This Radar requires two Antennas. Among which, one Antenna is used for transmitting the signal and the other Antenna is used for receiving the signal.
What do u mean by ambiguity?
Definition of ambiguity
1a : the quality or state of being ambiguous especially in meaning The ambiguity of the poem allows several interpretations. b : a word or expression that can be understood in two or more possible ways : an ambiguous word or expression. 2 : uncertainty.
What is integer ambiguity in GPS?
Source: GPS for Land Surveyors. The solution of the integer ambiguity, the number of whole cycles on the path from satellite to receiver, would be more difficult if it was not preceded by pseudoranges, or code phase measurements in most receivers. This allows the centering of the subsequent double-difference solution.
What is integer ambiguity resolution?
Carrier-phase integer ambiguity resolution is the key to fast and high-precision GNSS parameter estimation. It is the process of resolving the unknown cycle ambiguities of the carrier-phase data as integers.
What is phase ambiguity?
Phase ambiguity is produced by an interaction between ITD magnitude and sound frequency. (A) Phase ambiguity occurs because it is unclear whether the waveform in the right ear (grey) is delayed (ΔΦ1) or advanced (ΔΦ2) with respect to the waveform in the left ear (black).
What is integer cycle ambiguity?
But because we don’t know the true initial cycle count, the carrier-phase measurements are ambiguous by a constant integer amount (when measured in cycles). This characteristic of the observable is referred to as the integer ambiguity.
What is carrier phase ambiguity?
While carrier-phase measurements typically have very low noise compared to pseudorange (code) measurements, they have an inherent integer cycle ambiguity: the carrier phase, interpreted as a range measurement, is ambiguous by any number of cycles.