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Smarter Cars
Published in Patrick Hossay, Automotive Innovation, 2019
You might expect an automotive radar system to simply emit a narrow beam wave and measure the wave’s travel to define an object’s range. And, in fact, this is how radar units have functioned since World War II. However, this sort of approach is cumbersome, would be vulnerable to clutter and leaves something to be desired in accuracy. So, new automotive systems utilize continuous wave radar. Instead of measuring timing, the definitive measurement is frequency change. An uninterrupted wave is emitted with a frequency that constantly changes in some variation of a saw-tooth pattern, defining a frequency-modulated continuous wave (FMCW) radar. The frequency shift between the sending and received signal can be easily measured to determine distance; the greater the shift, the longer the distance.
Processing Data from Radar Measurements
Published in Zhengming Wang, Dongyun Yi, Xiaojun Duan, Jing Yao, Defeng Gu, Measurement Data Modeling and Parameter Estimation, 2016
Zhengming Wang, Dongyun Yi, Xiaojun Duan, Jing Yao, Defeng Gu
The basic working principle of continuous wave radar (CW radar) is that carrier frequency signals with a fixed frequency are transmitted from the transmitter, and the velocity is measured by the Doppler effect while the position is determined using time delay. This type of radars can measure velocity directly with high precision, while does not require many environmental conditions. MISTRAM system is a typical CW radar system. It consists of one transmitter and three receivers.
Length Measurement
Published in Rajpal S. Sirohi, Introduction to OPTICAL METROLOGY, 2017
In a more sophisticated modulation scheme, the optical frequency is varied linearly as shown in Figure 14.6. The frequency-modulated continuous wave radar can be used to measure accurately the range and the axial velocity.
A series-fed low sidelobe antenna for 24-GHz automotive radar
Published in Electromagnetics, 2023
Millimeter wave radar can directly measure the distance, radial velocity, and angle of target through an appropriate antenna system in dark light and severe weather (Waldschmidt, Hasch, and Menzel 2021). Common millimeter wave radars include continuous wave radar and pulse radar. Frequency-modulated continuous wave (FMCW) radar system is easier to measure the speed and distance of the target without requiring high output power of the transmitter (Thomas, Bredendiek, and Pohl 2019; Vasanelli, Bögelsack, and Waldschmidt 2018; Welp et al. 2020). Automotive radars are operated in 24 GHz band mostly for short-range applications, such as blind spot detection, lane change assistance, automatic cruise control, and parking assistance (Ho and Chung 2005; Lee and Kim 2010; Meinecke et al. 2013).
Measurement of soil water content using ground-penetrating radar: a review of current methods
Published in International Journal of Digital Earth, 2019
Xinbo Liu, Jin Chen, Xihong Cui, Qixin Liu, Xin Cao, Xuehong Chen
Currently, the FWI method is extended for different GPR antenna systems. For borehole GPR, a FWI scheme based on a 2D finite-difference time-domain solution of Maxwell's equations was first proposed by Ernst et al. (2007a, 2007b) and then improved by Meles et al. (2010) and Klotzsche et al. (2010). Klotzsche et al. (2014) and Gueting et al. (2015) successfully applied the FWI method based on borehole GPR in different experimental sites. For air-coupled GPR, Lambot et al. (2004a, 2004b) developed a FWI model specific to a monostatic ultra-wide band step-frequency continuous wave radar system. The reliability of this method has been validated in various laboratory and field hydrogeophysical applications (Lambot et al. 2005, 2006a, 2006b, 2008a, 2008b, 2009). Tran, André, and Lambot (2014) and Moghadas et al. (2014) tested this model for further improvement and application. The extension of the FWI for the ground-coupled GPR is less straightforward (Lavoué et al. 2014). However, Busch et al. (2012, 2014) introduced a FWI to ground-coupled GPR with promising results in large-scale measurement.
New Security Concepts for Advanced Reactors
Published in Nuclear Science and Engineering, 2023
Alan Evans, John L. Russell, Benjamin B. Cipiti
Figure 3 shows an example of a new PIDS that takes advantage of the new “enabling” technologies. The concept depicted is called the centralized radar–pan tilt zoom (CR-PTZ) module, and consists of a frequency-modulated continuous-wave radar, a bi-spectral PTZ, and the DMA algorithm. This design uses a radar capable of reliable detection out to 700 m. In the design proposed, the radar needs to provide reliable detection out to 240 m so the detection range needed in this design concept is well within the radar’s detection capability of the radar.