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osqzss / gps-sdr-sim

Software-Defined GPS Signal Simulator
MIT License
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BRDC/Hourly data #343

Closed ark-1313 closed 1 year ago

ark-1313 commented 1 year ago

Hi,

We are using the CDDIS hourly/daily data for the navigation data generation. We wish to generate the data for the current UTC. However, from the downloaded data it says that the timing (TOC & TOE) are invalid and hence will not be able to generate for the required time. This requires us to wait until the new data is released from the cddis. If we try over-riding using the 'T' option, it is observed that the receiver does not spoof at all.

  1. Is there any other way through which the TOC/TOE can be modified to get the data for the current UTC from the hourly/brdc file ?
  2. We came across another issue in which you suggested to use RTKLib with a receiver to process the raw data in order to obtain the ephemeridis. How long will the validity of a data obtained in such a manner be & how long should such a recording be done?

With Regards, ARK.

ark-1313 commented 1 year ago

Any help, anyone ?

osqzss commented 1 year ago
  1. It requires only a 18-sec long navigation massage (subframe 1-3), which repeats every 30 seconds.
ark-1313 commented 1 year ago

& we can generate data through the tool for the next 1 hour ?

What about (1) ?

osqzss commented 1 year ago

A broadcast ephemeris is typically valid for about two hours. Regarding question 1, the answer is no.

ark-1313 commented 1 year ago

Thanks a lot. Wonderful tool BTW !!