What is Dual Band GNSS?

Discussion in 'General GPS Discussion' started by Nuvi-Nebie, Feb 18, 2019.

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  1. Nuvi-Nebie

    Nuvi-Nebie Moderator

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    Dual Band (or Dual frequency) GNSS is an enhancement to the original 'GPS' system, it uses extra signals from satellites to provide much greater (sub-metre) accuracy.

    When satellite navigation was first made available for non-military use, it was a single set (or constellation) of 24 satellites operated by the USA, since then many more satellites have been added by various countries, some full constellations and some single or small groups of satellites intended to cover only part of the earth's surface, they include, Glonass (Russia), BeiDou (China), Galileo (European Union), ZQSS (Japan), NavIC (India) etc, the last two only cover their own countries, the term GNSS often refers to a system that utilizes more than one constellation

    In the first specifications for the GPS (USA) system, the transmitted signals from the satellites could be carried on up to 5 carrier frequencies ranging from L1 = 1.5GHz to L5 = 1.1GHz, although only L1 was available to non-military users

    Some websites have described satellite navigation units that can utilise more than one constellation as 'Dual Band', however this is incorrect, a Dual Band unit is one that can utilise more than one transmitted frequency (or carrier) from a single satellite, e.g. L1 + L5

    At present only GPS (USA) and Galileo (European Union), have a global systems of satellites that supply L1 + L5, (ZQSS (Japan) does this but not globally)

    Until recently only very costly surveying units were 'Dual Band', while navigation chips in smart phones and even dedicated GNSS products used only the L1 band , however there are now a few low cost devices in smart phones etc. that are truly 'Dual Band'

    WHAT IS REQUIRED FOR DUAL BAND?

    Obviously the minimum requirement is a device fitted with a navigation chip that can handle 'Dual Band' (L1 + L5), there are presently a few manufactures that are (or will be) supplying these devices for smart phones, tables etc. , devices that can do this include Broadcom BCM4775X family, Kirin 980, Snapdragon 855, Exynos9825 etc., however the presence of a 'Dual Band' chip on its own isn't enough, several levels of software also need to be in place, they include the correct level of Android and enabled L1 + L5 software.

    At present, this article only covers devices that run on the Android operating system, as I have no knowledge of any other devices, although Androids 7 and 8 had some enhancements for GNSS, all units will probably be running Andriod 9 as these newer devices are being shipped with, or upgraded to this new operating system, there is an Android App. that can help to show you what is happening with your device, it is called GPSTest, this name is not unique so here is a picture of the App. icon
    GPSTest.jpg

    Using this App. it is possible to see L/E1 and L5/E5a channels in the 'CF' column, the '5' entries are effectively the second 'Band', however the App. may not be able to get the info. it needs on all devices, even when the unit is working in 'Dual Band' mode

    L5-Screen.jpg

    In the composite GPSTest screen above, the double entrys of IDs 1, 30, 7, 21, 27, 30 and 195 are indications that two frequencies from the same satellite are being received, this is sometimes still visible even when the 'CF' column is not populated due to a lack of supporting software on the unit.

    WHICH DEVICES HAVE DUAL BAND?

    The following list has been gathered from various sources on the Net and will obviously change as time goes on, It will be updated when info. is available

    dual.jpg

    Reference1
    Reference2

    At least some versions of the following products are claimed to be working Dual Band or are Dual Band 'ready' :-
    • Asus RoG Phone 2
    • Asus Zenfone 6Z
    • Blackshark 2 SKywalker
    • Galaxy Note 10
    • LG G8 ThinQ
    • LG V50 ThinQ
    • OnePlus 7
    • OnePlus 7 Pro
    • OPPO Reno
    • Samsung Galaxy S10
    • Sony Xperia 1
    • Xiaomi Mi 9
    • Xiaomi Mi 9T Pro
    • Xiaomi Mi MIX 3
    • Xiaomi Redmi K20 Pro
    • ZTE Axon 10 Pro
    • ZTE Nubia Red Magic 3
     
    Nuvi-Nebie, Feb 18, 2019
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