The Difference Between IMU, AHRS, and INS

[Music] [Music] so often when customers come to the website or they're shopping around for a sensor an inertial sensor for their product they're going to often think of an ins and that's that's all they just heard ins but then that's that's not really the case maybe they actually need a imu which is actually super simple and they they're looking at a completely different price point so um understanding that there is a difference between an imu an ahars and an ins is going to help pick the right product for your specific application the the biggest misconception that people have about an ins is that it's just a gps it's not a gps it has a coleman filter in it it has a sensor fusion built into the device that gives you a much more accurate output it's a very high quality device generally so an ins is going to include a coleman filter which is going to consist of how the sensor itself fuses all of the individual parts into one and gives you a navigation output with everything incorporated this often includes gyro magnetometer and accelerometer and in the in an ins solution it also includes gps so it'll take those things and give you a navigation output that your robot can then use to understand where it is in the world you're looking to implement an imu it is important to recognize that it is just going to be magnetometer accelerometer and gyro sometimes magnetometer won't be included in that package and it will just be the random numbers that those little devices will end up spitting out and it won't have any smarts in it it's just going to pump out numbers where you would this would actually be very beneficial to use is in a camera a stationary camera that all you care about is just knowing whether it's pointing at the ground or pointing at the ceiling it's very basic not a whole lot to it but again there's no position or anything else to it a lot of people when they're looking for an a solution for their given application they're going to start at an ins level which includes the magnetometer gyro and accelerometer but it also includes a gps and it will fuse all of those sensors together to give you a robust navigation output that your system can actually use to drive around the world and knows where exactly where it's at [Music] so an imu actually stands for inertial measurement unit and that's that's all it is it's just a simple basic unit the next step up from there is ahars which stands for attitude heading reference system and that is going to actually include gps while it doesn't actually include a coleman filter it does give you all of the benefits of the imu plus a gps position an ahrs unit would be a good fit for the the people that already have a filter in mind that they've designed or already incorporated and they just want more sensor data pumped into it and then and then the the next step up from the ahars is the ins that everybody is familiar with the term ins and that one it stands for inertial navigation system and as the name implies it is a smart system it will take all of those sensors it will fuse them into an output that your system doesn't have to do anything more with it knows exactly where it is in the world based on just that output you don't need to send it to anything else the various sensors used in the device filter is actually a software package that the sensor outputs are fed into and then the coleman filter gives you a fused output that the rest of your robot can actually run on some of the extra special features that you can have that are exclusive to an ins is being able to use rtk rtk real-time kinematics is a process where you take a gps position from a base station and you output corrections over to your rover which is your generally your robot that's moving around and in doing this combination of two gps systems you're able to get centimeter level accuracy and this is only you can only do this with an ins system another feature that can only be used with a non-ins is actually compassing this is a newer technology but it is still only usable on an ins solution and what that is is where you take a gps one and you add a gps two you have two gps's for a single device but based off of the distance between those two gps positions you can then derive heading between the two and that gives you a very accurate heading dimension to your regular navigation system the reason why compassing is such a great improvement for an ins solution is because you're able to get down to a much smaller accuracy than say a magnetometer and a magnetometer is based off of an earth magnetic field and whether you're pointing north it's a compass but when you're using gps it doesn't care where north is really because it will always be able to drive your heading based off of those two gps's it's not going to be affected by a piece of metal going over it it won't be affected by your cell phone it'll just always work as long as you have a gps position so one of the the end-all be-all solutions that everybody really wants is well i can get great compassing position or encompassing heading well can i have position accuracy too with rtk and the answer is yes you can actually put them together um you just end up kind of doing a merge of the two you'll have your base station and then you'll have a rover that has two gps and it works the exact same way as rtk you get the base position information sent over to the rover and then it does its position fix and then it also can take the heading information off of the two gps positions and really give you a precise heading and position solution for your application [Music] the value of using an rtk base is that if you work any type of triangulation based off of that base you're able to get that position triangulation works on three points in this case you have an rtk base you have a satellite and then you also have your rover and based off of the dimensions of that triangle that you then draw is how we're able to actually get an rtk position down to the centimeter level of accuracy an ins with compassing still suffers from the basic gps position gps in general is hard to get better than one meter of accuracy encompassing is going to still suffer from that while we are able to derive an accurate heading given we have two rt or the two compassing positions on two gps positions on our our rover we cannot we cannot derive a more accurate physical position information out of those two you can average them but that won't give you any more [Music] accuracy [Music] you

Channel: Inertial Sense, Inc.

Views: 2,585

Rating: 4.9466667 out of 5

Keywords: ahrs, ahrs module, ahrs sensor, dual ins, gps antenna, inertial sense, autonomous navigation, autonomous robotics, robot operating system, robot localization, dual gps, imu, imu sensor, drone imu, what is an imu, uins, inertial, ins sensor, inertial sensor, ins system, ins robotics, inertial navigation system, ins navigation, inertial measurement unit, rtk, lidar, vslam, morgan rudolph, attitude heading reference system, kalman filter, rtk explained, ins meaning

Id: 4CZQQ0VLCG8

Length: 9min 23sec (563 seconds)

Published: Thu Mar 25 2021