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Questions tagged [gnss]

GNSS is a global satellite navigation system. GPS is the US GNSS.

A Global Satellite Navigation System (GNSS) is a system that uses satellites to provide autonomous geo-spatial positioning. It allows small electronic receivers to determine their location (longitude, latitude, and altitude/elevation) to high precision (within a few metres) using time signals transmitted along a line of sight by radio from satellites (Wikipedia).

GPS is the US GNSS. Other GNSS are used or under construction:

  • GLONASS (ex-USSR countries)
  • Galileo (Europe)
  • BeiDou-2 (China)

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What are satellite time, GPS time, and UTC time?

What is the difference between Satellite time, GPS time and UTC time? How are these calculated from one another?
Sourabh Jain
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If a GPS displays the correct time, can I trust the calculated position?

Suppose I plan to reactivate an airplane that has been stored in a boneyard for a year or two, or at least power it up and turn on the avionics. Also suppose for the sake of the question that the GPS does not remember its last position and needs to…
Steve V.
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Why did my phone's GPS receiver stop working when the plane was descending to land?

Recently, I flew on an Airbus A320. I turned my Lenovo A328 Android phone into airplane mode, and then used the default Maps app to watch my position using GPS. For most of the flight it worked normally. However, at the end of the flight, at about…
Ruslan
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How can I keep the data on a KLN89b GPS up to date?

I'm looking at a Mooney M20C with a pretty dated panel, but it's airworthy and could be a great opportunity to build some retrac time. The KLN89b GPS is IFR Certified, but is positively ancient. There seems to be a convoluted process to keep it up…
John Hoge
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Can the iPad use GPS data from a Garmin aera 660?

Can the iPad use GPS data from a Garmin aera 660 portable GPS unit? I assume this would happen via Bluetooth, if it's possible. I would like the more accurate WAAS data from the Garmin for use with CloudAhoy.
birdus
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Why do Computer Navigation Fixes still exist now that GPS waypoints can be used to define tracks?

A CNF is a point that defines a navigation track for a GPS, but why is it used when you there are GPS waypoints that are created to define a track?
nyorkr23
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Does Garmin G300 GPS use true heading or magnetic?

Does Garmin G300 GPS use true heading or magnetic? Sorry couldn't find this information anywhere else.
Shuheng Zheng
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GPS Magnetic Declination and current database

Can I fly with an expired GPS database if I verify the waypoints locations? or is the magnetic declination part of the database?
Rozh Ali
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Why do planes need line of sight for GPS to work?

Why is the below true when mobile devices such as mobile phones and designer watches with emergency beacons work without Line of sight? Most commercial aircraft transmit their GPS-based position twice per second. This is part of their ADS-B…
sclarius
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