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Certification and also a lot more technology behind figuring out when the position data is inaccurate. Aviation GPS units will run forward looking simulations (
by 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 agoThat's still a simple thing to do with software. The cost of the device shouldn't go up because of that.
- mikeash 11y agoThat 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 agoThe 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 agoAviation 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 agoMost GPS devices I've used provide a precision estimate already.
- mikeash 11y agoHow accurate is that precision estimate, though? Is it built with enough care that you can put lives on the line?
- hueving 11y agoAppeal 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.
- mikeash 11y agoIt's not an appeal to fear. It's an appeal to testing and verification.
- hueving 11y agoThe cost of these devices are much greater than the cost to implement the feature we are talking about though (alerting on bad precision). You can argue that the cost should be high because of intelligence about runway approaches, but just knowing that the precision is bad is not an excuse.