Test Drive: GPS-navigator against navigator with GLONASS / GPS

It is believed that the navigators GLONASS / GPS has a number of advantages in accuracy and stability over conventional with GPS-navigators. To see how this is true, it was carried out a test-drive navigation with GPS and GLONASS / GPS in urban environments.

Town:

Moscow

models navigators

Lexand ST-5650 PRO HD (GPS only)On the chipset SiRF Atlas V.
Lexand SG-555 (GLONASS / GPS), Chipset MStar.
program "Navitel 5" on both navigators installed.

test Subject

"Cold start" time (on the device to enable positioning) navigation stability, its accuracy and battery life navigator.

test conditions

Gadgets are not connected to the cigarette lighter, mounted on the windscreen next to each other. Program navigation is disabled, "the binding to the road" - it automatically "attracted" to the displayed Map the car to the nearest road and deprived us of the opportunity to see the difference in the accuracy of determination coordinates.

cold start

The inclusion of both navigators happened outdoor parking, well away from houses and trees that could theoretically interfere with reception satellite signal. "Cold start" the time was about the same - about four minutes for both devices.

On the broad street

When driving on the street is no problem Rusakovskaya was not seen nor GPS-navigator, nor his two-system counterparts. Is that the model only works with GPS, auto periodically "swerved" to the tram rails, then to the pavement.

District high-rise buildings

In the area of ​​high-rise buildings on the corner of Rusakovskaya and Third Ring Road periodic errors occurred in both devices. GLONASS / GPS sometimes "dropped in" on the lawns, but quickly corrected the error. GPS-navigator once to display, if the car passed through the house.

Underground parking

As a test site for testing was chosen underground parking "Auchan Sokolniki". Here GLONASS / GPS for the first time showed a clear superiority. In the narrow passage between the "Auchan" and the wall separating the territory from the railway, two-system navigator defined location without deviation. Navigator with GPS in the same conditions it displays the machine on the roof of the hypermarket, is on track.
Being under the roof, GLONASS / GPS lost contact only at the end of the congress parking, and GPS-navigator stopped working immediately. Similarly, on the road: GPS-navigator catch satellite signals only once under the open sky, trailing by 5-10 seconds on two-system model.

tunnels

At the entrance to the tunnel under Taganka Square two navigation satellites simultaneously lost. But in the place where the vault has clearance (approximately in the middle of the tunnel) GLONASS / GPS for some time, I resumed work and found several satellites. Navigator GPS with a single lumen ignored and became operational only at the exit of the tunnel.
The tunnel under Arc area, both devices show similar deviations and lost signal simultaneously.

District high-rise building

"Moscow City" was the only visited during the test site, where the navigator was able to "see" more than GLONASS satellites than GPS. Next to the capital's skyscrapers Lexand SG-555 receives a signal from the seven Russian satellites and five US. Lexand ST-5650 PRO HD at some point appear, that we are somewhere on the roof of a building.

Number of satellites

In the time of the test GLONASS / GPS-navigator all the time is displayed for about 9-10 GPS satellites and GLONASS satellites only 2-3. Many people mistakenly conclude that the GLONASS satellites is less than or worse than they work. In fact, setting the navigation software are, by default, that is the basic GPS navigation system for the device, and the Russian satellite constellation - more. That is, the availability of GLONASS fills GPS signal reception channels.

Energy consumption

The belief that the two-system navigators consume more energy, has not been confirmed. With the same battery capacity (950 mAh) GPS-navigator worked without recharging 1 hour 20 minutes, the navigator GLONASS / GPS - 1 hour and 35 minutes.

results

The results of the test are as follows: for travel in urban environments, in most cases it is sufficient GPS-navigator. But what navigators GLONASS / GPS in some cases, work accurately and reliably - confirmed fact.