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Is there a way to download GPS almanac?

I am trying to get my phone to update GPS information. I followed the instructions outlined in the Android question : how to reset and download A-GPS data? This seems to tell GPS to remove the "almanacs." I will assume that the next time my manual attempts to connect, he will also try to get an almanac.

This is not exactly what I am looking for, because (at least according to Wikipedia) GPS takes about 12.5 minutes to get a new almanac. It really has been so long, although I did not time it. Even 5 minutes seems like a long wait when I'm ready to start running.

When I hid, I came across the "GPS Status and Toolbox". This application downloads data via Wi-Fi or 3G. It is lightning fast and perfect for my needs.

Besides setting up data cleansing, I wonder if anyone knows how they perform data entry?

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2 answers

You are misleading two different methods to get the almanac needed for GPS to calculate user locations:

  • Reception and decoding of the almanac directly from the GPS satellite signal, which is broadcast in a navigation message. This is the part that takes 12.5 minutes (that is, to download the entire almanac from scratch. In practice, this is only necessary after a “cold start” of the GPS receiver). In general, a GPS receiver does not require an almanac to obtain a location decision. Instead, it performs a so-called sky search to determine which satellite signals are present.

  • Get almanacs from an alternative network (such as a cellular network) that is designed to provide such information. This method is also known as Assisted-GPS (A-GPS) . This is the method that smartphone-based receivers typically use, as it happens much faster.

The answer that you quoted concerns the second method, that is, the system message to get the updated almanac from the server.

For those who came to this page because of the heading "Is there a way to download GPS almanac?" and who want to really see how the almanac data actually looks, you can always download the current almanac data from the US Navigation Center .

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You must distinguish first

  • almanac
  • epheremides
  • model of putative ephemids

Almanac contains rough satellite curves, valid for a "long" time. After receiving the chip, you do not need to wait for it every time.

Ephemids contain a detailed satellite orbital module. They are valid for a short time.

Predicted ermides are ephemes that can predict up to two weeks. It must be downloaded from the server, this data is not available via GPS. And it can be proprietary for a particular GPS chip manufacturer.

You can install both almanach and epheremides on the chip, via (custom) NMEA or, as a rule, your own binary messages from GPS chips. How can this be done with a hack on Android, I can’t tell you. I expect Android to do this automatically without having to have a GPS Status Toolbox

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