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The new Block III GPS sats have a new civilian signal that will improve the quality of a fix as the ionosphere can be directly measured. Jury is still out on ho

The new Block III GPS sats have a new civilian signal that will improve the quality of a fix as the ionosphere can be directly measured. Jury is still out on how well the extra signal will improve accuracy as there isn’t a full set of sats that broadcast it yet.

lozenge 8y ago
Why are they improving civilian accuracy and will military still have more accurate fixes, or just less jammable signals?
- extrapickles 8y ago
  Most of the upgrades to the civilian bands are for faster first fixes and making it so a fix is consistently more accurate. Also the ionosphere can be directly measured by your gps receiver, so fixes will be more accurate. They are doing this because many civilian applications have emerged that need a more accurate signal (one is turn-by-turn navigation). When GPS was first developed, it was first envisioned as outputting coordinates and you looked up your location on a paper map, where 2m was better than most maps you could get. The military is getting the ability to get a signal that is 100x more powerful in a small area. It will be awhile before we see receivers using the new signal as the first of the new GPS sats launched today (some of the old ones are broadcasting the new signal, but not enough of them)
makomk 8y ago
That requires a dual-frequency receiver, though, which I think is only found in high-end survey equipment and a handful of very recent and expensive smartphones.
- b15h0p 8y ago
  Which smartphones are those? Is there a list somewhere?
  - ferongr 8y ago
    The Xiaomi Mi 8 is a relatively inexpensive flagship-grade device with L5/E5a capability.
    - johnjonesyc 8y ago
      better list of actual capability https://developer.android.com/guide/topics/sensors/gnss https://developer.android.com/guide/topics/sensors/gnss
    - losten 8y ago
      Unfortunately, even though there are already several phones on the market whose hardware supports dual band GPS, the software in most cases doesn't. see this article for details https://medium.com/@sjbarbeau/dual-frequency-gnss-on-android-devices-152b8826e1c https://medium.com/@sjbarbeau/dual-frequency-gnss-on-android...
      - ferongr 8y ago
        My Mi 8 with the stable Android P build seems to be using both frequencies for satellites "in use" at the same time. The actual benefits of it, I don't know though. https://i.imgur.com/dIlh5Mj.png https://i.imgur.com/dIlh5Mj.png

lozenge 8y ago

Why are they improving civilian accuracy and will military still have more accurate fixes, or just less jammable signals?

extrapickles 8y ago
Most of the upgrades to the civilian bands are for faster first fixes and making it so a fix is consistently more accurate. Also the ionosphere can be directly measured by your gps receiver, so fixes will be more accurate. They are doing this because many civilian applications have emerged that need a more accurate signal (one is turn-by-turn navigation). When GPS was first developed, it was first envisioned as outputting coordinates and you looked up your location on a paper map, where 2m was better than most maps you could get. The military is getting the ability to get a signal that is 100x more powerful in a small area. It will be awhile before we see receivers using the new signal as the first of the new GPS sats launched today (some of the old ones are broadcasting the new signal, but not enough of them)

makomk 8y ago

That requires a dual-frequency receiver, though, which I think is only found in high-end survey equipment and a handful of very recent and expensive smartphones.

b15h0p 8y ago
Which smartphones are those? Is there a list somewhere?
- ferongr 8y ago
  The Xiaomi Mi 8 is a relatively inexpensive flagship-grade device with L5/E5a capability.
  - johnjonesyc 8y ago
    better list of actual capability https://developer.android.com/guide/topics/sensors/gnss https://developer.android.com/guide/topics/sensors/gnss
  - losten 8y ago
    Unfortunately, even though there are already several phones on the market whose hardware supports dual band GPS, the software in most cases doesn't. see this article for details https://medium.com/@sjbarbeau/dual-frequency-gnss-on-android-devices-152b8826e1c https://medium.com/@sjbarbeau/dual-frequency-gnss-on-android...
    - ferongr 8y ago
      My Mi 8 with the stable Android P build seems to be using both frequencies for satellites "in use" at the same time. The actual benefits of it, I don't know though. https://i.imgur.com/dIlh5Mj.png https://i.imgur.com/dIlh5Mj.png