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Asked by: 1824 views General Aviation

Receiver Atonomous Integreity Monitoring. What is the purpose of RAIM??

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6 Answers

  1. John D. Collins on Apr 04, 2013

    RAIM is an algorithm that is used to determine if the GPS position can be relied on for the navigational accuracy a particular mode of navigation requires. For enroute, +/- 4 NM is required, for terminal operations +/- 1 NM is required. For a non precision approach, +/- .3 NM is required. If the accuracy can’t be assured, the GPS receiver generates an alarm indicating to the pilot that they can’t depend on the GPS for navigation and must use alternative means of navigation.

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  2. alaskanfly3r on Apr 05, 2013

    What is that +/- nautical mile about? Is that how much you can be off-course?

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  3. ccwebb on Apr 08, 2013

    The +/-NM is showing what the full scale swing of the CDI is. Between centered and full deflection will be +(right) or -(to the left) that many miles.

    A pilot is required to maintain at least Instrument Pilot PTS minimums of 3/4 scale deflection. In other words, 3.5 dot deflection. (Of course, ATC may still get on to you for being less off course.)

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  4. alaskanfly3r on Apr 11, 2013

    so the 4 NM to the right, and 4 NM to the left? and 2 NM to the right and 2 NM to the left and so on??

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  5. ccwebb on Apr 12, 2013

    Yes. +/-5 NM means that a CDI on the last deviation dot (the 5th dot) you will be 5 NM off course. Each dot would represent 1 NM, on this scale. When the scale changes the value of each dot would change as well.

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  6. alaskanfly3r on Apr 12, 2013

    well i guess that covers it for me. thanks john and ccwebb for providing me with some answers. much appreciated. safe flying!

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