It doesn't have precision and accuracy in any conditions, you can't use that for surveying and high precision project

It depends your location and the mobile device you're using.

The higher the number of GNSS satellites available at your location, the more accurate the coordinates you obtain.

Modern devices have an accuracy around ~3 meters which is good enough for navigation purposes but is - as Mehrdad Javadi said - not enough for high precision surveying.

A cell phone-based GNSS is about as good as a recreation-grade GNSS receiver (5+ m error on average, and even higher under vegetation such as trees or in an urban environment). To use horizontal positions determined with a cell phone-based GNSS in a scientific study that requires precisely determined positions would require the scientist to recognize this potential inaccuracy, and deal with it (rather than assume it does not matter).

Thank you all for your answers. Can someone explain me (if possible) why would a smartphone be less precise than a Scientific GPS ? I mean, if both use GPS+GLONASS+Chineese BDS, why would they be less precise ?

I'm surprised that no electronics company provides this type of device, a "scientific smartphone"

Furthermore, I don't really need more accuracy than 5 m, that's why I wanted to know if any smartphone is better than others for this. Advices ?

Dear Loris, summarising, the precision of a GPS receiver is primarily due to its capacity to receive a single or a double frequency (L1 and L2). The precision can be increased by a rtk correction, but I think that the receivers normally embedded in smartphones are single-frequency and are not allowed to receive such correction. A single frequency receiver without rtk correction has a precision of a some meters, as written above. If you don't need a high precision, you can take some measures for each point and then calculate an average of the coordinates. This procedure could reduce major errors and reduce the uncertainity inside the circle of 5 m, as you need. Unfortunately I can't give you advices because I use the smatphone's GPS only as road navigator.

Hello Loris,

I think that the first question that you need to answer is, what is the accuracy needed for your project. I know, the higher the better, but this is true only if your funds are unlimited.

First thing to consider is the device. I'm big fan of smartphones, but from my point of view, there are two significant drawback. First - primitive antenna. Due to miniaturization in cell phones they use primitive patch antennas, which cannot mitigate negative effects (multi-path etc.). Second - no differential corrections. In order to achieve centimeter or even decimeter accuracy you need differential corrections between two GNSS receivers (currently this is often solved using permanent observational services). However, until recently, smartphones did not provide raw data needed for such calculations. Now this is changing, but the data could be still insufficient due to poor antena design. From my point of view, if you'd omit smartphones, you can also omit recreational-grade and mapping-grade receivers without differential corrections (as these give you slightly higher accuracy for significantly higher price). Then, your next choice are mapping- and survey-grade receivers with corrections, but you need several thousands of Euros.

Second thing - measurement method. In principle, you can go kinematic or static. If you need real-time positioning, don't expect very high accuracy, especially with lower grade equipment. Measurement conditions are also crucial. Currently we are evaluating measurements with a survey-grade receiver. With 15 seconds observation time, we can achieve few centimeters under open area conditions, but almost 1.5m in forest...

Regarding smartphone GNSS accuracy, we tested several smartphones under open area and in forest (both leaf-on and leaf-off). The accuracy in forest was between 5-10m, while ~3m in the open area. Study is available here Article Horizontal accuracy and applicability of smartphone GNSS pos...

It's already a bit outdated, but perhaps it can give you some insight.

Other studies are available here:

Experiment Findings GPS (GNSS) accuracy of Lenovo Phab 2 Pro under conditions of...

Article Assessing absolute and relative accuracy of recreation-grade...

Regarding software, if you are using Android OS, I consider the Locus Map (https://play.google.com/store/apps/details?id=menion.android.locus&hl=en_US) the most versatile GNSS software. You can record track and points (also with text, audio or photo attachments), use various maps etc. The drawback is that Locus Map does not support GIS shapefile layers. If you need these, you can try Locus GIS or mobile QGIS.

If you need water/dustproof device, go for higher grade phone. Most flagships have some degree of it. If you need rugged phone, you can try Samsung Galaxy Xcover, CAT, or perhaps some chinnese brands.

Regarding multiconstalation device - in theory, more satellites= better position. I think that currently you will have problems to find a phone without at least GLONASS. New high-end chipsets support also Galileo, Beidou, QZSS.

In terms of brands and devices, I don't think that it would be possible to generalize and prefer one over the other. Just make a market research, search for user experiences, buy one and, most importantly, test it yourself. I think that this is crucial condition if you want to be "scientific". Even the same device with e.g. another OS update could achieve different accuracy.

Hi Loris,

- How accurate are smartphones GPS nowadays compared to scientific GPS ? If they are, which specifications should I look for ? Is GPS+GLONASS necessary ?

Depending on the environment, the number of supported constellations, the chip itself, smartphone GPS can be as good as 5m when used in standalone. I would say GPS+GLO is necessary and even encourage you to look for a device that supports also Galileo and Beidou to benefit from a higher number of satellites.

- Are there smartphone brands/devices that are better than others for that?

For high-accuracy you can buy a Xiaomi Mi8 (500 euro) smartphone with a dual frequency GNSS chip from Broadcom 47755. This phone tracks signals from GPS and Galileo on L1/E1 and L5/E5a and GLONASS and Beidou L1. With the trade war between US and China just be sure the phone can be delivered to your country. I would suggest to opt for delivery from an European warehouse (and the Global version) just to be on the safe side

- which apps are the best to record and read mapping data ? I'd like to record "ways" and "points"

Any GIS app from google store is good but depends on the specifics of your project.

Dear Loris,

I would suggest to start with the following links including phone and app information.

https://www.gpsworld.com/dual-frequency-gnss-smartphone-hits-the-market/

https://medium.com/@sjbarbeau/dual-frequency-gnss-on-android-devices-152b8826e1c

Hi Loris,

I realize I'm very late with this, but here is some further information on what smartphones currently have dual-frequency GNSS:

https://www.dignited.com/43490/most-phones-lack-dual-frequency-gnss-for-better-location-accuracy/

And here's a webpage that discusses actual results for various phones:

https://appandphones.com/whats-dual-frequency-gps-and-does-my-phone-have-it-accuracy-test-on-oneplus-7-pro-vs-s10/

Hi Loris,

It depend on the smartphone specification and details information are needed. GNSS smartphone able to use in open area. I am usual using GNSS smartphone to accuracy assessment of Landsat or Sentinel Imageries (If using very high resolution imagery, I recommend to use RTK GNSS types). Try Polaris Navigator (Android OS) to know an accuracy level.

These days several smartphones have a new chipset with dual band Galileo. It improves the measurments position pretty good. Especially near buildings/walls. I have´nt done any advanced statistics about it but you can tell its better than a normal smartphone from collecting positioning field data we´ve used previously. Todays date its only the phones listed below that have this feature. But tomorrow probably most "high end phones".

Huawei p30 pro

Google Pixel 4

OnePlus 7 Pro

Xiaomi Mi 8

dear Loris,

I wish you finished your research point. Me too search about GPS device with high accuracy and response to measure actual speed for vehicle.

Too, if anyone has any idea about how to measure actual speed for vehicle except : Radar and Fifth wheel methods

i will be welcome with his idea

thanks,