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One thing about the RPV/Quadcopter debate that is rarely mentioned is the reason why they don't use ADS-B transponders. The FAA requires ADS-B trasponders to h

One thing about the RPV/Quadcopter debate that is rarely mentioned is the reason why they don't use ADS-B transponders. The FAA requires ADS-B trasponders to have high accuracy GPS, and that pushes the cost to over $2,000 per device. It would be logical for the FAA to relax the GPS requirement slightly, so a cheap GPS module is sufficient to alert nearby aircraft of RPV activity over a certain altitude (eg. 200ft AGL) These RPV-grade ADS-B transponders could use a limited signal output, to avoid nuisance pop-ups from longer distances. The transponder Mode-S ID uniquely identifies the RPV. It would be possible for a transponder to use an alternate channel frequency, similar to how many General Aviation aircraft use 978Mhz ADS-B. Even with an alternate RPV channel, the RPV operators would still be alerted to regular aircraft operations.

lotu 11y ago
That is a fucking sane and logical idea, no wonder no one has mentioned it.
plantain 11y ago
There is nothing about aviation GPS's that make them high accuracy. In fact they're mostly inferior to consumer GPS equipment. What drives up the cost is certification of the equipment.
- swingbridge 11y ago
  Certification and also a lot more technology behind figuring out when the position data is inaccurate. Aviation GPS units will run forward looking simulations (for example when flying a GPS landing approach) and figure out that satellites are about to be in a suboptimal position and warn the pilot accordingly.
  - hueving 11y ago
    That's still a simple thing to do with software. The cost of the device shouldn't go up because of that.
    - mikeash 11y ago
      That makes no sense, unless your software guys work for free. The cost of software development has to be paid for out of the price of the devices. Aviation is a very limited market, so you don't have a lot of sales to amortize those costs.
      - comex 11y ago
        The sales volume of consumer GPS units, however, is extremely large; if there is any pure software improvement to be made, even if the benefit for those devices is quite low, I'd expect it to be commonplace. Does anyone have a citation for aviation GPS using more sophisticated algorithms than consumer GPS?
        mikeash 11y ago
        Aviation stuff isn't necessarily an improvement for consumer units, though. For example, an aviation unit used for precision approaches or collision avoidance needs to detect when accuracy decreases below minimums, alert the pilot, and disable the functionality. For a consumer unit you just keep pumping out inaccurate, best-effort numbers.
        JupiterMoon 11y ago
        Most GPS devices I've used provide a precision estimate already.
        mikeash 11y ago
        How accurate is that precision estimate, though? Is it built with enough care that you can put lives on the line?
        hueving 11y ago
        Appeal to fear isn't an argument. Either the precision is right or it isn't. Precision requirements aren't unique to aviation and aviation doesn't even have the strictest requirements. The required precision of surveying equipment is much higher than what aviation needs. I would have much more faith in an open source project with lots of people independently verifying the precision of calculations for known devices than closed source stuff from aviation companies that hide behind fear rather than real justifications for the price.
- neurotech1 11y ago
  From a practical perspective that may be true. Consumer GPS (eg. Phone/Tablet) is typically augmented GPS, whereas certified aviation GPS uses WAAS (Wide Area Augmentation System) to improve accuracy. The key difference is that aviation GPS will warn the pilot if there is degraded performance below requirements, whereas consumer GPS doesn't.
- jkaljundi 11y ago
  Here is one ICAO paper on ADS-B accuracy: http://www.icao.int/APAC/Meetings/2011_ADS_B_SITF10/IP10_AUS%20AI.%206%20-%20GPS%20Accuracy.pdf http://www.icao.int/APAC/Meetings/2011_ADS_B_SITF10/IP10_AUS...
- shoegumfoot 11y ago
  Aviation GPS typically have a greater update rate, and support WAAS (wide area augmentation system) and RAIM (receiver autonomous integrity monitoring).
swingbridge 11y ago
Interesting idea although there are a lot of technical issues that would make what you describe more challenging. A simpler approach is positive enforcement. Force manufacturers to hard code drones to not fly near airports or other restricted areas and not fly above 200 ft. Model aircraft have existed for a long time and there's been a good relationship with the FAA and few incidents. The challenge is that technology has advanced to the point that these modern "drones" are almost too easy to fly. Any idiot can watch some YouTube videos and then they think they're a pilot. Given that, to the extent possible the aviation regulations should be enforced at the device level to make these things as idiot proof in terms of busting airspace regs as they are idiot proof to fly.
- venomsnake 11y ago
  > Force manufacturers to hard code drones to not fly near airports or other restricted areas and not fly above 200 ft. A drone is one of the few things that can be smuggled by themselves. Both US-Mexico and US-Canada borders are wide.
  - dsfyu404ed 11y ago
    >A drone is one of the few things that can smuggle itself. Both US-Mexico and US-Canada borders are wide. Fixed that for you.
- threeseed 11y ago
  And if they add new airports or classified areas ? It also doesn't solve the problem of drones being active near emergency situations.
  - swingbridge 11y ago
    "Real" airplanes have the same issue. That's why all the charts and databases are updated frequently and pilots are responsible for ensuring the latest data is available and loaded into the onboard computers. On a typical small general aviation airplane that typically involves uodating the electronic flight bag app on your iPad and popping a new memory card into the on board navigation computer. Other short term updates (like firefighting flight restrictions) are reviewed by the pilots on official FAA endorsed websites or by calling a flight service center (like customer support for pilots) before each flight. One of the most basic elements of the required preflight planning for any flight of a "real" airplane is to do all the above to make sure you have the latest data and know about any temporary restrictions. There's no reason why drone pilots couldn't or shouldn't be required to perform a simplified version of the above before flight (if you want to do anything other than flying the thing under the treeline in your own backyard).
olex 11y ago
Just how accurate is this 2000$ GPS supposed to be? Because my 40$ Ublox M8N GNSS modules on several copters produce a solid lock with constant HDOP<1.5 under normal conditions, averaging around ~1.5m horizontal position deviation, and altitude is locked in via barometer down to several cm. To get more position accuracy, you really need DGPS, which AFAIK planes don't normally use either... and do those couple meters really matter?
- neurotech1 11y ago
  Its about certified accuracy. The UBlox or similar module could drift under certain conditions. From a practical point of view, knowing where the RPV is within a 100 meters would be more than enough. The $2000+ GPS is certified to provide position under Instrument Flight Rules for an RNAV (Required NAVigation performance) approach and landing. Not required for a RPV flown under 400ft visually.
downandout 11y ago
>that pushes the cost to over $2,000 per device. Sounds like a market that is ripe for disruption. $2,000 cannot be remotely close to the cost of production. This price is the result of having a small, wealthy customer base that is required by law to purchase it. If someone introduces one with pricing that reflects both the cost of production and a dramatically expanded customer base, that company will make a ton of money.
- cmdkeen 11y ago
  Just like medical devices or military hardware don't cost X to manufacture the cost is in the degree of certification required. Your MVP might look like it does all the same stuff but it is about proving things like mean time between failure, climatic conditions it can operate in etc.
  - downandout 11y ago
    In this case, any up-front costs, such as certification and R&D, can be amortized over each unit sold in the dramatically expanded market. If the market suddenly goes from a few thousand units per year to a few hundred thousand, the contribution that each unit sold must make to recoup up-front costs gets very close to zero.
- tankenmate 11y ago
  The cost isn't only about "production" per se; the increased cost also comes from meeting regulatory, reliability and testing requirements.
svensxds 11y ago
Very soon government will just throw everyone in jail, so there will only be full-time slaves without any rights

lotu 11y ago

That is a fucking sane and logical idea, no wonder no one has mentioned it.

plantain 11y ago

There is nothing about aviation GPS's that make them high accuracy. In fact they're mostly inferior to consumer GPS equipment. What drives up the cost is certification of the equipment.

swingbridge 11y ago
Certification and also a lot more technology behind figuring out when the position data is inaccurate. Aviation GPS units will run forward looking simulations (for example when flying a GPS landing approach) and figure out that satellites are about to be in a suboptimal position and warn the pilot accordingly.
- hueving 11y ago
  That's still a simple thing to do with software. The cost of the device shouldn't go up because of that.
  - mikeash 11y ago
    That makes no sense, unless your software guys work for free. The cost of software development has to be paid for out of the price of the devices. Aviation is a very limited market, so you don't have a lot of sales to amortize those costs.
    - comex 11y ago
      The sales volume of consumer GPS units, however, is extremely large; if there is any pure software improvement to be made, even if the benefit for those devices is quite low, I'd expect it to be commonplace. Does anyone have a citation for aviation GPS using more sophisticated algorithms than consumer GPS?
      - mikeash 11y ago
        Aviation stuff isn't necessarily an improvement for consumer units, though. For example, an aviation unit used for precision approaches or collision avoidance needs to detect when accuracy decreases below minimums, alert the pilot, and disable the functionality. For a consumer unit you just keep pumping out inaccurate, best-effort numbers.
        JupiterMoon 11y ago
        Most GPS devices I've used provide a precision estimate already.
        mikeash 11y ago
        How accurate is that precision estimate, though? Is it built with enough care that you can put lives on the line?
        hueving 11y ago
        Appeal to fear isn't an argument. Either the precision is right or it isn't. Precision requirements aren't unique to aviation and aviation doesn't even have the strictest requirements. The required precision of surveying equipment is much higher than what aviation needs. I would have much more faith in an open source project with lots of people independently verifying the precision of calculations for known devices than closed source stuff from aviation companies that hide behind fear rather than real justifications for the price.
neurotech1 11y ago
From a practical perspective that may be true. Consumer GPS (eg. Phone/Tablet) is typically augmented GPS, whereas certified aviation GPS uses WAAS (Wide Area Augmentation System) to improve accuracy. The key difference is that aviation GPS will warn the pilot if there is degraded performance below requirements, whereas consumer GPS doesn't.
jkaljundi 11y ago
Here is one ICAO paper on ADS-B accuracy: http://www.icao.int/APAC/Meetings/2011_ADS_B_SITF10/IP10_AUS%20AI.%206%20-%20GPS%20Accuracy.pdf http://www.icao.int/APAC/Meetings/2011_ADS_B_SITF10/IP10_AUS...
shoegumfoot 11y ago
Aviation GPS typically have a greater update rate, and support WAAS (wide area augmentation system) and RAIM (receiver autonomous integrity monitoring).

swingbridge 11y ago

Interesting idea although there are a lot of technical issues that would make what you describe more challenging. A simpler approach is positive enforcement. Force manufacturers to hard code drones to not fly near airports or other restricted areas and not fly above 200 ft. Model aircraft have existed for a long time and there's been a good relationship with the FAA and few incidents. The challenge is that technology has advanced to the point that these modern "drones" are almost too easy to fly. Any idiot can watch some YouTube videos and then they think they're a pilot. Given that, to the extent possible the aviation regulations should be enforced at the device level to make these things as idiot proof in terms of busting airspace regs as they are idiot proof to fly.

venomsnake 11y ago
> Force manufacturers to hard code drones to not fly near airports or other restricted areas and not fly above 200 ft. A drone is one of the few things that can be smuggled by themselves. Both US-Mexico and US-Canada borders are wide.
- dsfyu404ed 11y ago
  >A drone is one of the few things that can smuggle itself. Both US-Mexico and US-Canada borders are wide. Fixed that for you.
threeseed 11y ago
And if they add new airports or classified areas ? It also doesn't solve the problem of drones being active near emergency situations.
- swingbridge 11y ago
  "Real" airplanes have the same issue. That's why all the charts and databases are updated frequently and pilots are responsible for ensuring the latest data is available and loaded into the onboard computers. On a typical small general aviation airplane that typically involves uodating the electronic flight bag app on your iPad and popping a new memory card into the on board navigation computer. Other short term updates (like firefighting flight restrictions) are reviewed by the pilots on official FAA endorsed websites or by calling a flight service center (like customer support for pilots) before each flight. One of the most basic elements of the required preflight planning for any flight of a "real" airplane is to do all the above to make sure you have the latest data and know about any temporary restrictions. There's no reason why drone pilots couldn't or shouldn't be required to perform a simplified version of the above before flight (if you want to do anything other than flying the thing under the treeline in your own backyard).

olex 11y ago

Just how accurate is this 2000$ GPS supposed to be? Because my 40$ Ublox M8N GNSS modules on several copters produce a solid lock with constant HDOP<1.5 under normal conditions, averaging around ~1.5m horizontal position deviation, and altitude is locked in via barometer down to several cm. To get more position accuracy, you really need DGPS, which AFAIK planes don't normally use either... and do those couple meters really matter?

neurotech1 11y ago
Its about certified accuracy. The UBlox or similar module could drift under certain conditions. From a practical point of view, knowing where the RPV is within a 100 meters would be more than enough. The $2000+ GPS is certified to provide position under Instrument Flight Rules for an RNAV (Required NAVigation performance) approach and landing. Not required for a RPV flown under 400ft visually.

downandout 11y ago

>that pushes the cost to over $2,000 per device. Sounds like a market that is ripe for disruption. $2,000 cannot be remotely close to the cost of production. This price is the result of having a small, wealthy customer base that is required by law to purchase it. If someone introduces one with pricing that reflects both the cost of production and a dramatically expanded customer base, that company will make a ton of money.

cmdkeen 11y ago
Just like medical devices or military hardware don't cost X to manufacture the cost is in the degree of certification required. Your MVP might look like it does all the same stuff but it is about proving things like mean time between failure, climatic conditions it can operate in etc.
- downandout 11y ago
  In this case, any up-front costs, such as certification and R&D, can be amortized over each unit sold in the dramatically expanded market. If the market suddenly goes from a few thousand units per year to a few hundred thousand, the contribution that each unit sold must make to recoup up-front costs gets very close to zero.
tankenmate 11y ago
The cost isn't only about "production" per se; the increased cost also comes from meeting regulatory, reliability and testing requirements.

svensxds 11y ago

Very soon government will just throw everyone in jail, so there will only be full-time slaves without any rights