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I have a vehicle with a tracker installed. The device has a gps syst, 3-axis accelerometer, 3-axis magnetomet and a gyromeyet. Is it possible to determine by how much the vehicle rolled back on a slope or hill. Using gps angle wasn't an option as the angle given for short backward movement isn't always reliable. Can accelerometer be used in such a scenario??

230490
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  • Just to clarify; are you trying to measure the inclination of the vehicle, i.e. the angle of the slope it is on? Also, is the vehicle stationary? – cantunca Mar 17 '20 at 20:15
  • No. I want to determine, by what distance, the vehicle rolled back on a slope... Say my vehicle is on slope and i need to start moving forward again, i need to change my foot from brake to accelerometer to move ahead and at times this myt lead to roll back. So i need to determine, why wat distance it went back – 230490 Jun 15 '20 at 10:56

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You're right that the GPS angle (heading) will not help you in a single-antennae setup. On its own a GPS receiver needs a minimum distance of movement to determine heading.

A simple GPS receiver, when used without GPS corrections (which is the case for off-the-shelf GPS devices and mobile phones/tablets), has a minimum ~5 meter accuracy. That's why a short backward movement will not yield the desired results.

In construction/mining applications, there is often a fixed GPS base station nearby that broadcasts GPS corrections, which allows vehicle-mounted GPS receiver to apply corrections, reduce error and ultimately get centimeter-level accuracy.

So in conclusion, your 3-axis accelerometer will likely be the only sensor that you can rely on until your vehicle has rolled back at least 5 meters.

If your accelerometer is sensitive enough, you'll get measurable sensor values. However, if you rollback is very slow, where the G forces are almost imperceptible to the accelerometer, then you're out of luck.

This is assuming that you want near real-time detection of vehicle rollback.

El Stepherino
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  • I have a DGPS set up with correction applied and i get data in 3-5 cm accuracy. I need to determine by wat distance the vehicle rolled back, distance as small as 15cm needs to be captured, i need to know if the distance is greater than 15 cm or not. – 230490 Jun 15 '20 at 10:58
  • I thot may be i could use gps and take the location when the vehicle stopped on slope(point1) and then again keep monitoring the gps and whenever gps shows it moves ahead again(crosses the point 1), then calculate the distance between point 1 and the last gps before moving again to get the distance in cm. Not sure if this is the right way to go – 230490 Jun 15 '20 at 11:00
  • Absolutely. If you can keep track of your position samples from a receiver setup that gives you 3-5cm accuracy, then it can work. Since you'll likely want to track vehicle positional drift over a long period of time, you can store you positions on a "heat map" instead of storing each individual position (which over time would take up too much space). Keeping track of the initial and latest timestamps, you can determine drift velocity too. – El Stepherino Jun 15 '20 at 16:19