How to measure the real speed of our car using your phone?
How to measure the real speed of our car
Our GPS applications for measuring the speed at which you drive or travel in a vehicle. Available for Android and iOS:
Изтегли за Android и iOS:
Download GPS Speedometer for Android from here
Download GPS Speedometer for iOS from here
After recently buying a used car, Ivan noticed that there was a constant discrepancy between the speed shown on its speedometer and that of navigation. At certain intervals, the mileage readings differed dramatically from those of the navigation. At certain intervals, the mileage readings differed dramatically from those of the navigation.
This is an example story in which many people can recognize themselves.
Many other drivers over the years have reported discrepancies in mileage and navigation in their car. This situation is actually common to almost every car on the market. But why is that? Surely, car manufacturers can make their speeds accurate to the exact km / h or mph you travel.
How does a car speedometer work?
Speed is a measurement of distance over time. But car mileage doesn't really measure how fast you travel from point A to point B. Car speeds usually work by measuring the rotation of the car's drive shaft, axle or wheel. They then use basic mathematical formulas to extrapolate this rotation and determine how fast you are traveling. This is a very similar concept to a bicycle speedometer.
However, if the wheel / tire diameter changes, the extrapolation calculation will be incorrect. For example, the diameter will increase if you put new tires on the car (more tread that wears over thousands of miles) or increase the tire pressure. This means that for each turn of the wheel the car moves farther, which means that your speed is higher.
If the diameter decreases (eg - worn tires, less air in the tires, different brand of tire with slightly different sizes), then the car will travel a shorter distance for each turn of the wheel, therefore you will travel more slowly.
Vehicle mileage error limit
The differences in wheel diameter resulting from the above circumstances can be small (maybe a few millimeters), but at 50 kilometers per hour the wheels of your car rotate 6-7 times every second, so it can quickly make a difference of several kilometers per hour.
This error limit is taken into account when applying the law and the way manufacturers calibrate the speeds of their cars.
How does the GPS navigation speedometer work?
Satellite navigation devices (portable or integrated in the car) calculate the speed of your car by measuring the actual distance traveled over time using GPS satellite tracking.
They repeatedly find your exact position on earth via satellite and calculate how far you have traveled, then divide the time it takes to travel that distance. The accuracy of GPS navigation or the application is determined by the strength of the satellite signal and is not affected by the tires of your car or other vehicle.
Many navigation devices are not able to detect changes in the vertical direction, so they may be less accurate if you are traveling up or down a steep hill. They are also inherently more accurate at higher speeds, as the greater distance over time reduces rounding errors, but GPS navigation is usually much closer to the actual speed of the car than car's integrated speedometer.
Some factory-based satellite systems will also use in-vehicle data to integrate with the GPS signal to improve overall accuracy.
Why use our apps instead of navigation?
The advantage of our applications is that they are small in size (about 7MB for our application for Android based devices and 20MB for that for iOS), you can change the themes according to your taste, do not require much resource from the device and one of their largest advantages - have a timer to accelerate the vehicle from 0-100 km / h(or 0-60 mph).
Another advantage is that the app can be used to measure speed in any type of vehicle and any situation - you can put the phone on a stand on your bike, run the app and see the speed while traveling on the bus, check if a given car corresponds to the factory values of acceleration, ect.
How do I use your GPS application?
Download GPS Speedometer for Android from here
Download GPS Speedometer for iOS from here
- Run the app on your device
- Wait for a strong GPS signal
Done - the application is ready to work. If you want to measure acceleration from 0-100 km / h (0-60 mph):
- Select the acceleration mode
- Stop the car and wait for a good GPS signal from the satellites for the most accurate results
- Accelerate to 100 km/h(60 mph) from a standstill
If you want to do a new test, just stop, the application will restart the timer.
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