The major features include:
• Touch screen operation
• High sensitivity GPS
• Time mode(Alarm, Timer, Stopwatch)
• Rechargeable lithium-ion battery
• Operation time: up to 2 years for watch, 14 hours for GPS
• Built in flash memory to store 12,000 GPS data
• 10-seconds average speed display
• Support Doppler speed
• Google Earth KML/GPX format support
Q:Q1: How to improve the accuracy of GW52 speed measurement?A:Our main suggestion is to use GW52 in direct view of all satellites above horizon. This is a basic requirement for accuracy.
GW52 is a GPS-Doppler instrument optimized to measure SPEED (the magnitude of velocity vector).
The Doppler frequency shift df of each satellite carrier frequency (which GW52 measures and determines speed from) is df=velocity*cos(alpha)/c, where c is speed of light.
As you can see, the measurement of velocity relies on alpha: the angle between measured velocity vector and the direction to the satellite.
When satellite is in direct view, everything is fine: all alpha angles are well defined and the system has good accuracy.
When direct view of some of the satellites is blocked by gps-frequency attenuating objects, such as human body for example, the signal reaching GW52 antenna from these blocked satellites is a result of reflections, refractions, diffraction and all the interferences between them. What is the alpha angle that the signal comes from? Who knows?
This ambiguity in direction of GPS-Doppler signal is one of the main sources of speed errors.
Direct view of all gps satellites above horizon is required due to the physics of Doppler Effect.
The actual accuracy of GW52 depends on satellite distribution above the horizon in relation to measured velocity vector, but 1.3 cm/s accuracy (3sigma) in measuring 10s-average speeds above 100km/h have been observed.
To achieve comparable speed measuring precision in sport, GW52 must be worn on top of the helmet. All other locations on the body simply ruin the speed measurement accuracy.
Q:Q2: How do I set up GW52 clock?A:There are two ways to adjust GW52 clock
- Manually: you can enter “TIMER” adjust screen and adjust time manually
- GPS Time Synchronization (recommended):
Enter “GPS” mode and wait for GPS location fix.
Note the GMT time zone must be selected correctly.
Q:Q3: The screen is jumping around, how can I stop that?A:The GW52 touch screen is sensitive, in such case, please clean the screen with a dry, soft cloth. Then switch the device to the preferred screen, enable the screen lock function (START+MODE key)