The quality of the gps adapter?

Question

satellite navigation

Good afternoon,
I am developing a monitoring system, it is very important to minimize the price of devices, I initially chose the Digma Optima TT7000MG (because of the price), but the quality of the location, to put it mildly, leaves much to be desired (the error is about 900m - I have not seen such an error anywhere), Advise what to do with gps,
1. Choose another device? Then what gps parameters to pay attention to
2. Does the version of Android affect the accuracy of the determination (I have 4.4, the calculation algorithms may be changed in newer versions, although it is unlikely)
3. Or purchase a gps module separately?
I watched the quality of determining the coordinates on the tablet for 8k (some kind of Asus, Android 6) - there is an error of about 10 meters, what are the fundamental differences?
Thanks

Answer 1

the quality of the zhps is the sum of the quality of the zhps module + the quality of the antenna.
And if the circuitry of the zhps-module has now been worked out to perfection and there are no strong differences between the modules.
then it is physically impossible to shove a high-quality antenna into a small case.
The maximum that shines on a phone or tablet is a piece of a tin strip in the corner of the case.
accuracy with "open sky" for the phone + - 30 meters. to understand "where are you??" enough. in the high-rise building area will be worse.
For a visual comparison of the quality of zhps-modules, I advise you to record a track of "zero shift" i.e. put the phone in place, preferably in the open air for a couple of hours to record a track with a period of no more than a second.
Thus, only measurement errors will be present in the track.
You load it into any program and by the size of the blunder you can very clearly see how inaccurate the device is.
for exact numbers, you can distribute the points.

Answer 2

On the chip (module) GPS. The differences are most likely both in the type of module and in the size of the antenna.
I would recommend choosing a suitable tracker from the available ones. It's definitely a better antenna.