Is there a way to download the GPS almanac?

Question

I'm attempting to get my phone to update the assisted GPS info. I've followed the instructions outlined in question Android: How to reset and download A-GPS data? This seems to tell GPS to remove the "almanac" SO I'll assume the next time my handheld attempts to connect it will also attempt to get the almanac.

This is not really what I'm looking for, because (at least according to wikipedia) GPS take about 12.5 minutes to get the new almanac. It does indeed feel that long, though I've not timed it. Even 5 minutes seems like a long wait when I'm ready to start a run.

When i was skulking about, I came across "GPS Status & Toolbox." This app downloads the data via wifi or 3g. It's lightning fast and perfectly suited to my needs.

Beyond setting clearing the data, I'm wondering if anyone knows how they accomplish the insertion of the data?

Answer 1

You are confusing two different methods to obtain the almanac necessary for GPS to compute user locations:

1. Receive and decode the almanac directly from the GPS satellite signal, which is broadcast in its navigation message. This is the part that takes 12.5 minutes (i.e. to download the entire almanac from scratch. In practice, this is only needed after a "cold start" of the GPS receiver). In general, a GPS receiver does not require the almanac to obtain a position solution. Instead it performs a so-called sky search to determine which satellite signals are present.

2. Receive the almanac from an alternative network (e.g. cellular network) that is dedicated to providing such information. This method is also known as Assisted-GPS (A-GPS). This is the method that smartphone-based receivers will typically use, as it is much faster.

The answer you cited concerns the second method, i.e. telling the system to retrieve an updated almanac from a server.

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