Questions tagged [radar]

Anything related to RADAR (RAdio Detection And Ranging) systems, their operations and circuits. RADAR systems are used to detect and locate a target by sweeping a beam of microwaves across a region of space and detecting echo signals reflected by the target.

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76 views

How does the author get to his equation for the ellipse and the antenna's beam?

I am trying to understand how the author of this textbook (Basic Radar Analysis by Mervin C. Budge) realizes the equation for the ellipse shown in the image attached labeled Figure 2.3 (found in ...
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60 views

Confusion on what the RF input to a PLL does

I am designing an FMCW radar, for which I need to generate an RF signal ramped in frequency. To accomplish this, I want to use a direct digital synthesizer (DDS) to generate the ramp at baseband then ...
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49 views

Can traffic counting be done with just doppler radar?

I'm planning on using radar to count car traffic on a slow speed road. What I'm wondering is if I should expect doppler radar to be good enough to get an accurate count? Alternatively I could also use ...
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Need help with the choice of a motion sensor for use in arctic temperatures

We are a group of students, who are currently investigating how to build a robot that is meant to work at arctic temperatures (peaks at roughly -30 degrees Celsius). We would like to equip our robot ...
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Why is my clipping circuit involving 1N5819 Schottky diodes in my radar receiver not working?

I have built the circuit shown below and been testing it on a breadboard. Everything works except the positive half clipping circuitry. I need it to clip after 3.3V. It currently just clips below 0V, ...
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41 views

FMCW radar sensor for vital sign signal processing

In order to get started with radar signal processing in MATLAB, I want to capture the heart frequency and respiration of a person with a FMCW radar. I only want to do post signal processing in MATLAB, ...
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99 views

Low Voltage Oscillation in OpAmp Circuit

I have a small signal from a radar sensor (in the range of 300 µV) which I want to amplify to something I can reliably measure. Fortunately the application notes of the sensor provide a recommended ...
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47 views

Uniform circular array (UCA) beamforming using FFT

As far as I know, conventional beamforming using FFT can return a range-angle map. However, this only works with a uniform linear array (ULA). I'm wondering if the same approach works for UCA. I guess ...
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186 views

How do I compute the angular resolution of a radar system?

I hope this is the right place to ask a radar related question, otherwise I would be grateful for a pointer to the correct forum. I want to compute the angular resolution of a radar system but so far ...
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129 views

What is the difference (and the link) between the RADAR cross section (RCS) and the equivalent area of the target?

Here it is written that: The radar cross section (RCS) σ of a target is the equivalent area seen by a radar. It is the fictitious area intercepting that amount of power which, when scattered equally ...
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What is the purpose of range gating in a tracking mode of a Radar?

I am trying to understand what happened in the famous incident where the Patriot failed to intercept a Scud missle because of a software bug. The reprot can be found here. Why does the radar need to ...
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Which is the cause of "scan losses" in a linear phased antenna array?

in a linear phased array it is possible to move the peak angle ("beam steering") by applying proper phase shift between the excitation currents: The second picture represents the array ...
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Pulse Doppler radar system simulation using MATLAB

How to code this project in MATLAB I'd tried coding this project (prob. 3-2, third paragraph) in MATLAB through this tutorial : https://www.mathworks.com/help/phased/ug/doppler-shift-and-pulse-doppler-...
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113 views

Stm32 dma for IQ modulation

I’m trying to develop an application where I use an stm32f405rgt6 microcontroller ic to drive a radar that operates in multiple ism bands (433.92 MHz, 915 MHz, 2.4 GHz and 5.8 GHz). The overall idea ...
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78 views

FMCW Radar Signal Processing based on MIT Open Course

I am working on a self-made FMCW radar - for the signal processing, I am using the MIT open course (https://ocw.mit.edu/resources/res-ll-003-build-a-small-radar-system-capable-of-sensing-range-doppler-...
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Friendly target identification in radar

Crossposted from Signal Processing stack exchange, How do radar systems identify friendly targets to avoid AA locks during combat scenarios? Do friendly planes broadcast a known signal or is something ...
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How to plug CAN Bus radar to Pixhawk Cube Orange flight controller?

I want to plug my radar (which is a CAN Bus) to my Pixhawk flight controller. (https://ardupilot.org/copter/docs/common-thecubeorange-overview.html)I bought the radar from China and the site i bought ...
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A question on single-sided baseband signals

Can anyone provide insight on whether a radar is able to exploit a real baseband signal that has a single-sided spectrum?
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183 views

Is the impulse response of a real system is always a real function?

As stated in the title, is the impulse response of a real system is always a real function? Can it ever be complex/analytic, etc.? I'm more interested in terms of radar systems. Any info would be ...
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29 views

Estimating Safe Pulsed RF Power given Continuous Wave Power Rating

For a university project I am designing a RADAR transmit/receive module at 9.4 GHz. Right now I'm working on an input power limiter to protect an LNA, but my colleague designing the LNA quotes its ...
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120 views

Building a 77GHz Band FMCW Radar with 0.25 Degree Angular Resolution

First some context. My group recently acquired some hardware for a radar related project, specifically a Texas Instrument AWR1843Boost (https://www.ti.com/tool/AWR1843BOOST) and a Texas Instruments ...
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203 views

FMCW radar FFT(Fast Fourier Transform)

I am trying to design a simple FMCW radar for the ideal case. Below are steps I planned. Transmit signal, Tx = cos(T) receive signal, Rx = cos(R) Mix transmitted signal and received signal, Sx1 = cos(...
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744 views

What is beam coupling coefficient for linear beam klystron?

What does beam coupling coefficient exactly tell? For eg. a voltage gain coefficient tells how much times the input was amplified. So what does beam coupling coefficient tell, like does it tell how ...
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53 views

Typical power reflected off wall/window/wooden shelves etc

For interference purposes, I would like to quantify how much signal power I would receive back when my transmitted signal is reflected off an object (a wall, glass window, wooden shelf) at a distance ...
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135 views

Feasibility of rat-race as RF mixer without active devices

My understanding is that RF mixers generally use some sort of active device (sometimes diodes) to produce output rich in harmonics, and rat-race couplers can be used to get the sum or difference ...
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107 views

Finding a material transparent to 26GHz radio waves for radome protecting a radar rangefinder probe

I want to use a 26GHz radar probe to measure water levels for some outdoors applications. These are pretty common devices, one manufacturer among many others is for example: https://en.supmea.com/...
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110 views

HB100 Range extension with Dish Antenna

I have interfaced HB100 sensor with ATMega Microcontroller. It easily detects my hand movement upto 5-6 inches only. I want to extend range of the sensor so that it detect movement upto atleast ...
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181 views

Why does medical ultrasound use pulses instead of chirps?

My background is in radar where it's quite common to use chirped excitation signals (i.e. pulse compression). I have noticed that this method seems to not be used in medical ultrasound. Why not?
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91 views

How do we tell distance to target at the receiver from frequency modulation?

Was thinking about radar and how to tell distance using FM. If you send a wave with a consistent wavelength of 1 meter, and it hits a target 1000 meters away and then comes back, it will have gone ...
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How does stretch processing work for SFCW?

I've been reading about FMCW radar, and I understand that a chirped signal can be de-chirped by mixing it with a copy of itself, which yields a beat frequency which is much easier to process and is ...
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186 views

Best waveform for Radar

I was wondering what would be the best waveform to generate for a phased array short range imaging radar? Square, sine, etc. Also what frequency would be best to operate at for the carrier wave given ...
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341 views

IC / logo identification: 5.8 GHz radar MMIC marked "5810"

Can anyone identify the pictured IC or the manufacturer logo on it? It's a 5.8 GHz radar MMIC with 1 Tx, 1 Rx, PLL, power amplifier, mixer, and low noise amplifier, presumably from an Asian ...
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289 views

How to calculate Doppler Shift for multipaths from moving objects?

Let's say we have a radar where the transmitter and receiver are placed together, and form an angle theta with a target object moving with velocity ...
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397 views

Why use convolution for pulse compression in radar instead of correlation?

I have not understood the way to process pulse compression in radar signal processing. I think it's correct to use correlation for pulse compression, but I saw many materials about pulse compression. ...
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66 views

Resonant Radar -- How aspect independent is it? [closed]

Resonant Radar: transmitting at a bandwidth that encapsulates nearly the natural resonance frequency of a reflective object in hopes of illuminating it upon return (higher amplitude.) I have read ...
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62 views

Geometric spreading of an impulse antenna

I am new to radar and curious about the geometric spreading in free space. I set up an air-coupled antenna about a half meter above the ground, with a large PEC on the ground. Then I adjusted the ...
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62 views

What do you believe was meant by FEA?

( RCS = radar cross section ) FEA wasn't mentioned in the acronyms or keywords list.
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121 views

Sampling Frequency of a pulsed radar signal

I'm new to radar. please excuse my question if it doesn't make sense to you. In a pulsed radar signal, why is the required sampling frequency "2 times the inverse of pulse width" instead of "2 times ...
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167 views

Can two Radar motion sensor, running next to each other, result a false detection?

I have two CDM324 Radar motion sensors. I want to run the two sensors close to each other. The transmitted frequency is roughly 24 GHz and I am afraid that a small shift in one sensor transmitted ...
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1k views

Does this VCO produce a sine wave or square wave

I'm looking at the datasheet for the analog devices hmc431lp4 voltage controlled oscillator, and I can't tell if its output waveform is a sine wave or square wave. The datasheet doesn't label the ...
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442 views

Signal processing in FMCW and SFCW

With regard to signal processing, how is frequency modulated continuous wave (FMCW) radar similar/different from stepped frequency continuous wave (SFCW) radar? Do we actually modulate the RF carrier ...
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5k views

How does LIDAR avoid getting confused in an environment being scanned by hundreds of other LIDAR?

(Meta: I do not know an appropriate place for this on Stack Exchange. There does not appear to be any groups related to autonomous driving technology and computer 3D vision / perception systems.) For ...
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Why do the Duga-1 dipoles look like an array of birdcages?

Looking for sources for the question What Soviet signals attempted to scramble communication and sabotage Apollo missions? I ran across the Wikipedia article for Duga Radar. Below are cropped and ...
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Pulsed Power Charging Resistor and Choke

I am currently attempting to build a pulsed power supply that requires an 8 H inductor to produce 50 kV 17 A square pulses with widths of 100 uS. Please see the attached schematic for more details (...
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172 views

radar attenuation calculations

I would like to ask a few questions that are probably not difficult for engineers to figure out. Personally, I am not an engineer but want to learn about radars. I am having trouble understanding the ...
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444 views

Meaning of 'Scatterer' and 'point scatterer' as opposed to just using the word 'target'?

https://earth.esa.int/web/guest/missions/esa-operational-eo-missions/ers/instruments/sar/applications/radar-courses/content-3/-/asset_publisher/mQ9R7ZVkKg5P/content/radar-course-3-the-radar-equation "...
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What is meant by "doppler extent"?

A google search of "doppler extent", Where I found the term: Extracting Target Features from Angle-Angle and Range-Doppler Images 1993 - ‎Cited by 5 - ‎Related articles Doppler extents (as for ...
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Radar and Standing Waves

I have a doubt about the working principle of a simple Radar. Consider a stationary object, which does not move with respect to our transmitter. We send an electromagnetic wave to it, and it will ...
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Measured doppler shift error biggest on direct flight on target

Following scenario: There is a radar on a plane which emits a CW Signal and outputs the measured doppler shifts from the reflection of a static target. I can see from the data, that the error of the ...
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2k views

Is it common practice to connect power supply to a DB9?

I got a project where many sensors which uses CAN were connected to a DB9. And sensor power (24V and GND) too. I want to connect the DB9 terminal to power however how can I do it in a safe way? If I ...