Hello, well, I want to get the linear and angular velocity of a vehicle based on the data of IMU and GPS. all the exemples I saw so far in the internet do a sensor fusion using Kalman filter to get the position not the velocity. Also we can get the transformation matrices between two set of points from the roll, pitch and Yaw angles, but I wonder if I can get the linear velocity taken t0 position as [0,0,0] and then devided the distance between two points over the timestamp. Actually the probleme here is the linear velocity because the angular velocity is already provided from the gyro. Pease any help will be appreciated.
Dear Rayane,
I suggest you to see links and attached files in topic.
-kalman filter - How to fuse linear and angular data from sensors ...
https://robotics.stackexchange.com/.../how-to-fuse-linear-and-angu...
-How to transform acceleration data to velocity data - ROS Answers ...
answers.ros.org/.../how-to-transform-acceleration-data-to-velocity-...
-Motion Tracking Algorithms for Inertial Measurement - Semantic Scholar
https://pdfs.semanticscholar.org/.../2a4a2fbbd3b3fa3242c70f4866...
-Orientation and Displacement Detection for Smartphone ... - IEEE Xplore
https://ieeexplore.ieee.org/iel7/6287639/7859429/07748482.pdf
-RPM measurement using MEMS Inertial Measurement Unit (IMU)
https://csce.ucmss.com/cr/books/2018/LFS/.../ESC3700.pdf
Best regards
Dear Rayane,
Most of the GPS module provides the data in NMEA format consisting longitude, latitude, and altitude information which can be converted to the linear position in ECEF frame (Using Geodetic to ECEF transformation matrix) or other coordinate frame using similar transformation. The NMEA data also provides the highly accurate timestamps. The rate of change of these positions will give linear velocities.
So basically, it is possible to get the linear position and velocity using only GPS sensor.
Also, the angular velocity is readily available from the gyroscope output of the IMU.
However, the update rate of the GPS sensor is very low (1-5 Hz) with an accuracy of about 2-5 m and requires good coverage (at least 4 reachable satellites) which makes them unsuitable for indoor applications or while traveling through a tunnel for example.
On the other hand, measurements provided by the inertial sensors in the IMU module, are used to track the position, velocity, and attitude (orientation) of an object relative to a known start position, velocity, and attitude. It does not rely on any external information sources that can be disturbed or jammed, which makes it suitable for applications where coverage could be an issue. Further, it has a high update rate (≥ 100 Hz) which is one of the most important requirements in various autonomous systems.
However, the errors in the inertial sensors grows with time and so an IMU module that uses low-cost inertial sensors can only be used for a very limited time period.
GPS and IMU complements each other and can be fused to give better performance and to overcome the above stated problems.
The advantage of fusing theses sensors are as follows.
(1) high position accuracy
(2) orientation information
(3) high update rate
(4) for shorter time periods can provide estimations even during GPS receiver outage
(5) faulty GPS measurements can be detected and rejected, thereby making the overall system more robust.
The article below provides one of the several ways of fusing these sensors.
https://instructure-uploads-eu.s3.eu-west-1.amazonaws.com/account_87790000000000001/attachments/677996/Localisation2018.pdf?response-content-disposition=attachment%3B%20filename%3D%22Localisation2018.pdf%22%3B%20filename%2A%3DUTF-8%27%27Localisation2018.pdf&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAJKYS55LTKAJVWK3Q%2F20181113%2Feu-west-1%2Fs3%2Faws4_request&X-Amz-Date=20181113T063234Z&X-Amz-Expires=86400&X-Amz-SignedHeaders=host&X-Amz-Signature=9cf305317fec7049ac81c58aafa6f405dd9ea26250d214a8dc7deae0b37d96ea
I hope this helps!
Best,
Deepak
Thank you all. Now am trying to go through all what you've provided me.
Deepak Gala for the article you gave, I couldn't open it, can you give me the title please and I'll search on it.
Hi I know pass long time but I want to same thing. Did you solve this problem. If you solved, can you share us your code?
Hi fatima, actually, I didn't completed it but I recommande Deepak Gala answer.
Take a look at the report Sensor fusion - GPS+ IMU by Isaac Skog
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