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"Minimum" time required to receive all data in the GPS navigation message.

Started by Horsa, June 14, 2010, 10:13:15 AM

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Horsa

Q: What is the minimum time required to receive all data in the GPS navigation message?

Latest GlobalTop GPS engines will determine the updating and refreshing timing automatically. The time required for update depends on the current calculation stage and environment. If the receiver has not been operated before or has not been in operation for a very long time, the minimum time required to receive all data in the GPS navigation message (including RTC, ephemeris and almanac) is 12.5 minutes. It is hard to say for a receiver that already contains partial messages, because the GPS engine will automatically determine which data it needs and which data it will need to update.

One more thing: the minimum of 12.5 minutes depends on the receiving conditions, because it takes 30 seconds to receive 1 page of the GPS navigation message (of a total of 25). If the data for a particular page is missed due to bad reception, it must wait for another cycle.

One way to speed this process up is using AGPS, but this will depend on your applications because it will need a windows compatible system for pre-loading ephemeris update (Extended Prediction Orbit).