# GPS Short distance calculations, accuracy limitations for 1-30 meter distance [closed]

I am a total beginner in the field of GPS, and this is actually my first post.

But, I have been looking into some of your questions, and especially the ones for short distance calculations, and time calculation used to measure traveled distance.

I want to measure distances from one coordinate to another with distances varying from typically 1-30 meters with an accuracy of 0.5 percent. Is it possible, and how can it be done? Or what is possible?

Update:

I want to create a small unit to measure short distances as mentioned above. So to be more specific, it will have a digital display and measure the distance from a coordinate 1. (0,0,0), to coordinate 2. for example 10 meters away. I will choose the location for the coordinates pressing a button on the unit, and the distance will show on the screen in meters and centimeters.

So for the accuracy, I actually believe that 2 percent accuracy is enough in the range between 1-30 m.

I am open for all types of measurement methods.

## closed as off-topic by per1234, Milliways, sempaiscuba, VE7JRO♦, gre_gorSep 20 '18 at 20:13

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "This question does not appear to be about Arduino, within the scope defined in the help center." – per1234, Milliways, sempaiscuba, VE7JRO, gre_gor
If this question can be reworded to fit the rules in the help center, please edit the question.

Take a look into Differential GPS, 10cm accuracy

Differential Global Positioning Systems (DGPS) are enhancements to the Global Positioning System (GPS) which provide improved location accuracy, in the range of operations of each system, from the 15-meter nominal GPS accuracy to about 10 cm in case of the best implementations.

Each DGPS uses a network of fixed ground-based reference stations to broadcast the difference between the positions indicated by the GPS satellite system and known fixed positions. These stations broadcast the difference between the measured satellite pseudoranges and actual (internally computed) pseudoranges, and receiver stations may correct their pseudoranges by the same amount. The digital correction signal is typically broadcast locally over ground-based transmitters of shorter range.

The United States Coast Guard (USCG) and the Canadian Coast Guard (CCG) each run DGPS systems in the United States and Canada on longwave radio frequencies between 285 kHz and 325 kHz near major waterways and harbors. The USCG's DGPS system has been named NDGPS (Nationwide DGPS) and is now jointly administered by the Coast Guard and the U.S. Department of Transportation’s Federal Highway Administration. It consists of broadcast sites located throughout the inland and coastal portions of the United States including Alaska, Hawaii and Puerto Rico.[1] Other countries have their own DGPS system.

https://en.wikipedia.org/wiki/Differential_GPS

GPS is typically 3 to 4 meter accuracy. 0.5% of 1m is 5mm. 0.5% of 30m is 15cm. So you can pretty much instantly rule out using GPS for what you want.

So what are your options? Well, that very much depends on exactly what you want to achieve, and what your environment is.

• If you have a limited area you will work within (e.g., a race track) you could consider multiple RF or IR beacons and triangulate signal strength between them
• If you are looking to obtain speed between two fixed points (chronograph) then some sensors to detect when the target object passes those points would be better

To better advise you on the best technology for your application you will have to give far more detail about what your actual application is. Don't just assume that, because GPS exists, that it is always the right solution for every problem.

• I just updated my question from your comment.. hope this will make it easier to understand. And I looked into your link to the GPS accuracy.. So that didn´t look too promising.. Thanks ! – Emhob Sep 20 '18 at 13:01