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Minimum signal requirements for EASY (Embedded Assist System)

Started by Horsa, March 23, 2012, 03:35:25 PM

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Horsa

Q: What are the minimum signal requirements for MediaTek EASY (Embedded Assist System) function?

EASY is a self-generated orbit prediction function for shorter time-to-fix supported by GlobalTop GPS receivers based on MediaTek MT3339 chip. The EASY function is enabled by default.

The GPS receiver will calculate and predict automatically the single ephemeris (up to 3 days) when the power is on, and save the predicted information into memory. The GPS engine will use these information for positioning if not enough information is received from the satellites. Therefore the function will be helpful for positioning and TTFF improvement under e.g. indoor or urban conditions. The backup power voltage (Vbackup) shall be supplied.

The minimum signal requirements for a full prediction are:

  • at least 5 minutes full operation
  • at least 6 satellites in view
  • at least a carrier-to-noise ratio (C/N) of 40 [dB Hz] for each satellite in view
If these requirements are fulfilled, a GPS receiver with EASY enabled is expected to fix within 5 s after a warm start. This includes also restarts after the module has been powered off with Vbackup supplied continuously and reliably.

We are not aware of a maximum number of satellites for which the orbit can be predicted. It is therefore to be expected that the orbit data are predicted for all 32 satellites of the GPS constellation under the above conditions.