Printer FriendlyEmail Article Link

Positioning Application: Why doesn't PosApp apply a fixed offset to my multipath when I have set power levels to absolute

  • PosApp
  • All signal Types
  • Multipath - Fixed offset
  • Power levels set to absolute (for more info on absolute power levels please view


  • If the multipath fixed offset does not appears to have been applied to channels with 'absolute' power it is because the order in which the settings were applied are incorrect
  • The INCORRECT order would be setting channels to 'absolute' power before applying a fixed offset multipath setting
    • When multipath is added to a channel that has 'absolute' power it automatically adopts the power level of that channel
  • The reason for this is because a channel with 'absolute' power will never change, it retains it's setting regardless of what SV or Multipath takes over the channel
  • The image below shows an example of what you'd see if you were to apply multipath after setting a channel to absolute mode


The areas highlighted in red clearly show that SVID 3, channel 1, has a mulipath signal with 20dB attenuation added.

But in the power adjustment window multipath 1, channel 2 has not applied the 20dB offset. This is because channel 2 previously had SVID 17 allocated to it with an ABSOLUTE power level of 10.99dB. The multipath signal has adopted the power allocated to channel 2. This is correct for 'absolute' power mode

In order to use absolute power levels and still apply a fixed offset multipath you must do the following:-

  1. Leave channels in 'Relative' mode (this is default)
  2. Apply any fixed offset multipath to any SV's that require it
  3. Change channel(s) power levels to 'absolute'
  4. By doing this you allow PosApp to apply multipath Relative to the LOS signal, then you tell the channels to retain those levels Absolutely

Product : PosApp