Questions tagged [sensor]

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Best way to reach experts in the Synthetic Aperture Radar (SAR) Simulation field?

I'm looking for Synthetic Aperture Radar (SAR) Simulation experts and struggling to find them (context: synthetic data for geospatial applications). I've found a few users in this community who could ...
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19 views

Smartphone acceleration data to path

I try to calculate smartphone path based on acceleration data. I drew a triangle on the table using my device and now I want to generate a path. I use following formula: ax = (ax[i] + ax[i+1])/2 ay = (...
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1answer
31 views

Clustering FFT frequency bins from sensor time series data

I am trying to analyse multivariate time series data sets. I have 6 signals for each event, representing 3 linear accelerations and 3 rotational velocities for a 40ms window. I am trying to find a way ...
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1answer
38 views

sensor data windowing and normalization

I am getting up to speed with working with sensor accelerometer data. I am looking to conduct a FFT on this signal. I found that the signal being non periodic is causing issues so I have tried to look ...
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1answer
33 views

Kalman filter for heading estimation with magnetometerv + gyroscope only considers magnetometer

I implemented a Kalman filter to estimate the heading of a robot that is moving in 2D, given the measurements coming from a magnetometer (X, Y) and a gyroscope (Z). The code is the following: ...
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30 views

Using lock-in amp to measure pulsed signal

I am working on a design of an acoustic resonator for sensing application, I use an excitation field at a certain frequency (a), and measure the response of the sensor (b), for my application, I only ...
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1answer
46 views

Time-frequency analysis of a nonlinear system

I have empirically developed a sensor failure detection system which works fine. The system receives inputs from different types of sensors. Because of noise characteristics, I use low pass filters on ...
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11 views

Optimal fiducial marker design for signal registration

I have scalar, time series data being produced by a set of measurement devices. For simplicity, assume that all the devices operate at the same sampling frequency (I can always interpolate if not). ...
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55 views

How to determine sampling rate of a lock-in amplifier?

I am trying to figure out the sampling rate of a lock-in amplifier and how it is related to the time constant. For example, imagine measuring sinusoidal waves at $1$, $5$, $10$, and $50$ Hz ...
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119 views

Space-Time Finite Element and Static Condensation for Sensor Fusion

My recent pastime interest deals with the nonlinear sensor fusion of GNSS, barometer, magnetometer, accelerometer and gyroscope data. I had a look at the EKF, UKF and Particle Filters but gave up as ...
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41 views

How do I turn my sensor samples into a cleaner, more useful curve?

This is for one of my fish tanks, which has dimmable LED lights. It's a bit of an experiment where I'd like to see what'll happen if the "sun" above the tank "rises" and "sets&...
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1answer
41 views

Trying to do frequency analysis of an accelerometer output

I am new to signal processing. I have a 3 axis MEMS accelerometer. I have read its output into $\mbox{Matlab}^{\tt TM}$. My problem is that the signal I am trying to isolate has a frequency of about 0....
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44 views

FFT requirements of real time signal from sensors

I have an electrical current sensor which generates measurements every second. I want to calculate the FFT of this signal. Since my real-time values are received every second, I think that the fastest ...
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1answer
359 views

Kalman filter with multiple sensors

I have been reading more about EKF and I am a bit confused on how you handle predictions with multiple sensors. Ex, I have IMU, GPS, Odom and Stereo Camera. Each can be used to predict location, how ...
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86 views

How to get a depth map from a Kinect 360 depth sensor?

I'm trying to understand how Kinect 360 depth sensor works. At the moment, I know that this sensor is composed by an infrared pattern generator and a infrared camera. IR camera gets the pattern ...
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17 views

Accelerometer drift: What hardware-level signal conditioning operations are being performed under the hood of a MEMS accelerometer chip?

I'm in a debate with a peer who says that filtering accelerometer signals at the chip-level has nothing to do with mitigating the problem of drift Often, additional software-level filtering is ...
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2answers
79 views

Speed from Depth/Pressure sensors

I have a pressure based Depth sensor. For reference, MS5837-02BA. All depth measurements I've been able to read are very accurate (±1cm) I tried experimenting to find out the speed of the body by ...
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3answers
305 views

Averaging data from 2 sensors

Suppose we take a reading of a single rotating axis using 2 identical sensors. Intuitively, I think that averaging the outputs of both sensors will yield a less noisy result. But what if sensor A has ...
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65 views

Using a Kalman filter to clean acceleration data

I am collecting acceleration, gyroscope and magnetometer data in all 3 directions. I would like to filter noise from the accelerometer using a Kalman filter. I am not trying to esimate orientatoin or ...
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1answer
47 views

How significant is the time lag between inertial IMU data in a inertial analisys?

I'm working on a MCU system that use an IMU (ICM-20948) which has two different chip inside: one provides accelerometer and gyroscope data at $1125$ Hz (configurable at $125$ Hz), the other one ...
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1answer
186 views

Finding Minimum SNR or Minimum Detectable Signal Based on Noise Spectral Density

Imagine I have an $n$-bit sensor, whose noise spectral density is $V/\sqrt{Hz}$. $V$ is an exemplary measurement unit. The desired measurement bandwidth is also known. Is there a mathematical way to ...
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1answer
44 views

Accelerometer Inference from power spectrum

I have 3d accelerometer data sampled as 60hz. When I am looking at the power spectrum in all three accelerations (x,y,z). I am noticing a trend with a negative slope. I trying to figure a few things ...
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1answer
119 views

What is the driving Voltage?

While I was looking into ultrasonic transducer in order to transmit and receive a beam, I came across specification of a transducer stating driving voltage as 20Vrms. I am not sure what actually does ...
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19 views

Equalization of ultrasonic transducer [duplicate]

I am working with ultrasonic transducers with frequencies 100 kHz, one for transmission one for reception. The transmitted signals are chirps. I would like to measure the time of flight between ...
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1answer
23 views

I want to get tilt sensor value for a given time t_0, but the tilt sensor data points are discrete. How do I interpolate between the discrete points?

I have 3-dimensional readings from a tilt sensor (specifically these are rotational angles about X, Y, and Z axes) over time. Let's call these angles S. I want to infer S at a specific time t_0, but ...
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26 views

Extracting time-tagged pulses from Geiger audio recording

I am doing some tests with SmartGeiger detector designed for smartphones. The sensor unit sends pulses via phone microphone jack input and the app does the counting and calculates the values. However,...
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3answers
248 views

Is it better to use sampling rates which are a power of 2? 32-64-128-256-512Hz? instead of using for example 30- 60-100-250-500Hz?

I am recently working with a sensor that I its sampling frequency can only be configured to either 32hz- 64hz- 128hz-256hz... and I was wondering whether using such sampling frequencies have any ...
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1answer
57 views

Estimating Real-Time Vehicle Velocity from low-frequency GPS, accelerometer, gyro and magnetometer in Smartphone

I am trying to write a system that would be able to estimate the velocity of a traveling vehicle (usually a car) using a smartphone. Most smartphones have the next sensors: 1Hz Low-Frequency GPS 10-...
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66 views

What does Allan variance really means? [duplicate]

Let a sensor (e.g. accelerometer) with a combination of white gaussian noise and random walk noise. The loglog plot that is usually shown as function of a time parameter, affine decreasing for a ...
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1answer
233 views

How to understand the sum of all "fourier frequencies"?

I got the data of an acceleration sensor to analyze. It consists of special terms of 30 Hz, 60 Hz and 120 Hz. In the following you can see in the first plot the 60 Hz data and in the second one the ...
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2answers
39 views

Can amplitudes be used to differentiate one signal from another?

I have use case, where there are lot of sensors placed under ground.The sensors give amplitudes each second.So my aim is to detect if some anomalous activity takes place at that point. IF an activity ...
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2answers
896 views

Fourier transform of a noisy signal

Let's suppose i have a sensor that measures the output of a process and this cause a not negligible noise that affects my signal. My goal is to analyze the process signal in order to find faults. How ...
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36 views

SciPy - Distinguish between two group of periodic samples [closed]

First of all, I'm sorry for my bad English writing, plus, I'm new to DSP. Background We have got motion data of 20 cows. 10 cows are healthy and 10 cows are slightly lame. Lameness is an abnormal ...
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1answer
43 views

How to get discrete values from a nosiy data set that have a trend?

I have a sensor that produces values over time (appr. 50/sec). I visualized these values (X axis is the time), this can be seen on the picture, measurement A and B - these are two independent ...
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50 views

pressure decay filtering

So, I've been dealing with a series of pressure decay curves from a pressure transducer. Each one has a waterhammer effect as a consequence of shutting down pumps. Here are examples of 3 curves: I'm ...
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1answer
377 views

Getting Vario (m/s) from a bmp180

I am building a variometer as a hobbie, this could be a duplicate from an existing question: How to use Kalman filter for altitude prediction based on barometer data? . Details follow: I have a ...
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1answer
236 views

Reduce noise of sensor by combining two

I've had the basics of signal in university but little real-life practice. I've got an acceleration sensor with a digital output signal (signed 16 bit value). This signal is a little noisy. The ...
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1answer
145 views

Inverting Sensor Transfer Functions?

When you see software packages that read in data from sensing equipment, does the software do something to inverse the transfer function? Correct me if I'm wrong in my understanding, but this is how ...
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1answer
634 views

Kalman Filter - How to combine data from sensors with different measurement rates?

I'm trying to implement a Kalman filter for tracking the position of a vehicle with the help of position data from GPS and Odometry measurements. The GPS data (WGS84 format collected from an app on an ...
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2answers
1k views

Minimum sample frequency of IMU accelerometer and gyroscope

I was wondering how I would justify a sampling rate of 125 Hz for accelerometer and gyroscope data from wearable sensors. This is a rate used in a lot of biomechanics literature, but I can't seem to ...
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85 views

How to draw a smooth spectrum from a discrete array of measurements at selected frequencies?

I have a AS7265x triad spectroscopy sensor from SparkFun (link) which gives me measurements at 18 individual light wavelengths between 410nm and 940nm. The datasheet says that the FWHM of each sensor ...
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27 views

Signal ECG , collecte & visualize data

I am currently working on a sensor that visualizes an ECG signal and visualizes its data. Its principle is that it has 3 electrodes that must be placed in specific parts of the body .... I would like ...
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1answer
2k views

What type of low-pass filter to use for gyroscope filtering in control application?

I am using a gyroscope to generate a feedback signal that drives a motor to resist rotation, just as in a camera gimbal. The gyroscope is sampling at 32 KHz with a bandwidth of 8 KHz, and my control ...
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40 views

Is my Kalman Filter model reasonable? Using for a 3 wheels rover platform

Background: I'm building a 3 omniwheel rover platform that looks something like this: It has 1 IMU sensors on each of the wheels (3 in total). So in theory, I can get gyroscope and accelerometer data ...
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1answer
321 views

Bias instability in Gyroscopes : AVER / ADEV

I am attempting to implement allan variance to determine the amount of bias that is shown in my IMU's gyroscope ( BMI160 ). I am doing this with the following formula, that was captured in the ...
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1answer
2k views

How to interpret Allan Deviation plot for gyroscope?

Regions with different slopes correspond to different types of noises in Allan Deviation plot of a steady gyroscope at steady temperature. My doubts are: What is significance of x axis in this plot, ...
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97 views

Rocketry : Combine two accelerometers to reduce noise?

I am designing an IMU for an experimental rocket. I'll be using the BN055 9DOF that has sensor fusion - orientation quaternion - and gravity compensation. My main goal is speed computation, and I was ...
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1answer
113 views

Handling a number of simultaneous measurements in Extended Kalman Filter?

If I have a number of sensors whose measurements arrive at the same time - how can I handle them properly in the Kalman filter? P.S. The measurements are not necessarily taken at the same time but I ...
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3answers
248 views

Kalman Filter Sensor Processing

Kalman filter achieves convergence of state vector by using sensor observations. Assuming a sensor such like velocity sensor, giving two axis velocity information in X-axis as well as Y-axis(see edit ...
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1answer
37 views

Is there a closed form solution for a temporal calibration of two different signals?

Given two signals $f_1(t),f_2(t+dt)$ where $t$ is time and $dt$ is the time delay between the two signals, is there any closed-form solution with respect to $dt$? what are the efficient global ...