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Just FYI that not all countries require equipment for space based ADSB ( like the USA ). Many of our commercial airliners have it but mostly in the name of trav

Just FYI that not all countries require equipment for space based ADSB ( like the USA ). Many of our commercial airliners have it but mostly in the name of travel abroad.

crote 3y ago
What kind of equipment does an airplane need for "space-based" ADS-B? Isn't it just satellites capturing the regular air-to-ground ADS-B signals?
- jffry 3y ago
  Wikipedia [1] says that there are two challenges: - ADS-B can be broadcast on two frequencies (978 MHz and 1090 MHz). FAA requires aircraft operating above 18000 feet to use 1090, while either may be used by craft flying lower. (It seems like the equipment is less expensive). This means 1090 is used more heavily by large commercial craft and so 1090 is the only band the satellites currently listen to. - Smaller private craft sometimes use belly-mounted antennas and so their hull can block signal propagation upwards [1] https://en.wikipedia.org/wiki/Automatic_Dependent_Surveillance%E2%80%93Broadcast#Satellite_(space_based)_ADS-B_Collection https://en.wikipedia.org/wiki/Automatic_Dependent_Surveillan...
- stevehawk 3y ago
  historically, aircraft have those antennas mounted on their belly and with low power they blast them at the ground for powerful receivers to catch. For "ADS-B Diversity", which is the space based version, on a generic Cessna 172 that meets current ADS-B requirements, I would need to rip out my current ADS-B system and replace it with a $9,000 (plus labor) ADS-B system that has dual broadcasting antennas. I think the top mount antenna is also more powerful but I honestly do not know. Space based ADSB only improves coverage for mountain ranges and oceans. It's mission in a mountainous situation is to fill the gap when radar coverage is lost but you have low altitude (in relation to ground, not sea level) traffic, such as arriving and departing traffic. assuming this map is accurate, you can appreciate how aircraft below 15,000 ft would be constantly falling in and out of ADS-B coverage if they themselves were changing altitude.

Just FYI that not all countries require equipment for space based ADSB ( like the USA ). Many of our commercial airliners have it but mostly in the name of travel abroad.

crote 3y ago

What kind of equipment does an airplane need for "space-based" ADS-B? Isn't it just satellites capturing the regular air-to-ground ADS-B signals?

jffry 3y ago
Wikipedia [1] says that there are two challenges: - ADS-B can be broadcast on two frequencies (978 MHz and 1090 MHz). FAA requires aircraft operating above 18000 feet to use 1090, while either may be used by craft flying lower. (It seems like the equipment is less expensive). This means 1090 is used more heavily by large commercial craft and so 1090 is the only band the satellites currently listen to. - Smaller private craft sometimes use belly-mounted antennas and so their hull can block signal propagation upwards [1] https://en.wikipedia.org/wiki/Automatic_Dependent_Surveillance%E2%80%93Broadcast#Satellite_(space_based)_ADS-B_Collection https://en.wikipedia.org/wiki/Automatic_Dependent_Surveillan...
stevehawk 3y ago
historically, aircraft have those antennas mounted on their belly and with low power they blast them at the ground for powerful receivers to catch. For "ADS-B Diversity", which is the space based version, on a generic Cessna 172 that meets current ADS-B requirements, I would need to rip out my current ADS-B system and replace it with a $9,000 (plus labor) ADS-B system that has dual broadcasting antennas. I think the top mount antenna is also more powerful but I honestly do not know. Space based ADSB only improves coverage for mountain ranges and oceans. It's mission in a mountainous situation is to fill the gap when radar coverage is lost but you have low altitude (in relation to ground, not sea level) traffic, such as arriving and departing traffic. assuming this map is accurate, you can appreciate how aircraft below 15,000 ft would be constantly falling in and out of ADS-B coverage if they themselves were changing altitude.