GitUser275
commented
6 years ago Later the same day, with no changes to the configuration or options but after a restart of all apps, the Avare display showed pressure altitude format tags. In this condition the traffic could not be suppressed with the preferences/display/"Show ADSB traffic within given feet of aircraft". This filter had worked for the condition shown in the first post.
Note that GPS altitude (from Android phone GPS) is shown as "MSL ft" for both cases and GPS is not flagged invalid. It appears there is an inconsistency in the selection and/or validation of the altitude being used to determine if relative altitude should be used for the traffic tags.
Compare data for NKS564 which is at FL370 and which is displayed as 37000PrA'. This is a correct tag which is not using local GPS altitude for correction to relative. (I don't know if the design intent is to use GPS altitude for relative tags or if only ownship pressure altitude is used).
apps4av
Test configuration: Stratux v1.4r3 with dual SDR, AHRS with pressure sensor, but no GPS Moto G android phone with integrated GPS but no baro sensor Avare ver 7.8.5
Test condition: On ground with Moto G providing GPS position and Stratux providing an ADS-B data stream that does not include the periodic ownship report. (Statux should provide ownship report with no GPS connected and this issue has been logged by Statux)
Observation: Traffic is shown with a tag in relative altitude format but the displayed altitude value is target pressure altitude not target relative altitude. The following screen shots were taken in the order displayed. They show that AAL1246 was flying at FL360. The target tag for AAL1246 shows +36000'. Ownship GPS altitude is 1250 ft. For this condition the target tag should either have been 36000 PressA or +34750.