Improving GPS on MTK devices, Especially on Lenovo
Improving GPS on MTK devices, Especially on Lenovo – I got this article on the russian Lenovo forum, maybe you interesting and wanna fix GPS on your device, so read and understand it.
What is “Chinese” GPS and how to fight it … or why not working GPS on CN (and not only) devicesThe bulk of the owners of mobile devices brought from the capital city of China and not only faced with the problem of “not working» GPS. Why in quotes? Because it actually works, the problem is not on the device (or GPS-receiver), and in running with the device almanac of GPS satellites. In this topic I will try to briefly reveal a theory of GPS-positioning and explain how without deleting and editing any system files, including gps.conf, calibrate and customize your device to work correctly with GPS.
* A small digression for amateurs and professionals straightening and replacement gps.conf – this file in OS Android 4.4X (aka KitKat) is absent.
First, a little theory
– GPS ( Global Positioning System ), in a literal translation – Global Positioning System.
The GPS system operates on the basis of orbiting satellites that are in six orbits, whose height is about 20,000 kilometers, and the velocity is 3000 m / sec (i.e., daily for each satellite completes two “spiral” around the Earth). Data from satellites are transmitted on two frequencies – both civilian and military. We omit the military, our device is not available, but a civil (1575.42 MHz) allows for error less than 3 meters ( declared by the error of 10 meters smartphones or GPS navigators caused international or other laws on the use of GPS for civilian purposes )
GPS satellites transmit two types of data – the almanac and ephemeris .
– Almanac – contains the parameters of the orbits of all the satellites. Each satellite transmits almanac for all satellites. Almanac data are not very accurate and are valid for several months.
– Ephemeris – the exact coordinates of each satellite, adjusting the parameters of its orbit and clock (these data are not collected in one day, based on the tracking of its orbit and position in the sky, not only on Earth, but also of other celestial bodies). Taken separately GPS satellite transmits data only own ephemeris. Retransmission of satellite ephemeris occurs every 30 seconds. These data are not valid for more than 30 minutes. If the GPS-receiver was switched off for more than 30 minutes, and then re-enabled, it starts looking for satellites, based on his famous anthology. According to the data recorded in the almanac, GPS satellites to select and initiate the search. Now imagine – not only that our GPS smartphone / tablet does not work more than a few months, so it has taken a couple of hundred thousand kilometers from the last-place calibration. From here and “grow legs” in “does not work” GPS.
To our built-in GPS device wound up he needs Almanac of the satellites in the area and their ephemeris.
Creating almanac and ephemeris receipt
* To create an almanac and ephemeris receiving satellites requires ROOT access
* All the procedures recommended in the open, or at least on the street
Turn on GPS (this requires lower “blind” and click the icon GPS )
Once in the engineering menu phone to navigate to the tab Location and go in YGPS
On the tab “Satellites” should be red dots (that satellites), and below them (bottom) signal scales. If the signal scales absent, and satellites (red dots) is, it is said that the satellite phone sees, but can not connect to it because of incorrectly recorded anthology.
For proper operation of the GPS to create a new almanac, in line with our current location :
In paragraph YGPS go to the tab “Information”, and then, with an interval of 5-10 seconds, alternately press the button “full“,”Warm“,”hot“,”Cold“(thus causing a complete reset of the old almanac).
Warm, Hot and Cold – there are three modes of starting the GPS receiver :
- hot – time, position, almanac and ephemeris are known, takes a few seconds
- Warm – time position with some restrictions and almanac known. Ephemeris from at least 3 satellites, known since the last shutdown.
- Cold – time coordinates are known with some restrictions. Almanac and ephemeris are unknown.
- Full, most likely it through all three modes to search for satellites
After that, go to the tab NMEA Log and click on the start – will burn and create new Almanac
After you run the NMEA Log turn on the tailgate “Satellites“and wait for 5-10 minutes until the phone itself does not find all the satellites and connect to them ( * not necessarily all ).
Indication of the connection are “greenish” point satellites (remember before that they were red) and “suddenly” earned scale satellites (will bottom) We are waiting until the scale also changed its red color to green.
When the GPS receiver records the satellite, then it shows “empty” bar signal strength. At this point, yet there is a process of data collection ephemeris. When ephemeris of each satellite is adopted, the corresponding signal strength bar turns green, and the data received from the satellite are suitable for navigation.
After connecting to the maximum number of satellites back to the tab Nmea Log and click “stop“.
Exit the engineer mode, launches Navitel (Yandeks.Navigator, MapFactor: GPS Navigation, Igo Primo or others. To taste) as well as the status of GPS, Google Maps, GPS and other GPS Test app and enjoy life.
And finally, a few words about 2D Fix and 3D Fix
2D Fix and 3D Fix it two modes of error correction using GPS
GPS has its own system of quality criteria for receiving a signal – DOP (Position Dilution of Precision, deterioration of positioning accuracy). DOP quality depends on the ability of GPS [receiver] corrected signals from satellites.
Availability 3D fix is not a sufficient criterion of quality. If more than 6 DOP indicates poor signal quality. Less than 4 – enough to record tracks OSM (openstreetmap – street map). Less than 2 – very good quality.
- When 2D Fix correction occurs based on latitude and longitude
- When 3D Fix correction occurs based on latitude, longitude and altitude
Therefore, a good DOP’a can achieve even with 2D fix
Finally fly in the ointment from Navitel:
I do not know 9 (current) version of the program (maybe fixed a), but in the 3 and 5 versions so accurately, DOP is missing. No, of course it is (without it would not work), but only corrects the error in the horizontal (HDOP) and vertical (VDOP) planes
PS In order to calculate the exact coordinates with GPS navigation enough to connect to only three satellites.
Video Guide :
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