Building a GPS Receiver - Part 1: Hearing Whispers
https://axleos.com/building-a-gps-receiver-part-1-hearing-whispers/
Have you ever noticed that your Maps app still works during a flight? It can feel illicit, like someone just forgot to turn off the signal, and that watching yourself crawl along the earth should be done without drawing undue attention.
A few months ago I learned that there were only around 30 GPS satellites serving the entire planet. This piqued my interest, because it reminded me of the 13 root DNS servers from which all resolution flows. Perhaps GPS has a similar design in which the ‘source of truth’ is diluted by several layers of signal repeaters?
I navigated to gps.gov, and was presented with this delightful image. I became even more excited to learn about what these satellites do!
I decided to try my hand at decoding these GPS signals, guided by the vague end-goal of plucking out my position from peanuts.
I learned that the GPS signals that facilitate our mapping apps are ever-present, around us at any altitude, in any weather conditions, at all times.
This sounds cool in the abstract, but the tangible reality is staggering. These signals are all around me as I write this. They’re all around you as you read it. The world is soaked in these whispers, repeating themselves endlessly for anyone willing to listen.
You can find out exactly where you are, from thin air, anywhere at any time, by learning to speak the language of the electromagnetic waves flowing over your skin. These waves have been a constant and quiet companion for most people’s entire lives.
GPS is perhaps one of the most audacious geo-engineering feats ever undertaken, and its traces can be felt with just an antenna and a motive.
nym
npub1hn…whtl5
2024-04-18 15:31:06
Author Public Key
npub1hn4zhxzsd5w4m5kvq326gqnsrc6zcakhparw8pee4tw7wlxw70ysawhtl5Published at
2024-04-18 15:31:06Event JSON
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"content": "Building a GPS Receiver - Part 1: Hearing Whispers\nhttps://axleos.com/building-a-gps-receiver-part-1-hearing-whispers/\n\nHave you ever noticed that your Maps app still works during a flight? It can feel illicit, like someone just forgot to turn off the signal, and that watching yourself crawl along the earth should be done without drawing undue attention.\n\nA few months ago I learned that there were only around 30 GPS satellites serving the entire planet. This piqued my interest, because it reminded me of the 13 root DNS servers from which all resolution flows. Perhaps GPS has a similar design in which the ‘source of truth’ is diluted by several layers of signal repeaters?\n\nI navigated to gps.gov, and was presented with this delightful image. I became even more excited to learn about what these satellites do!\n\nI decided to try my hand at decoding these GPS signals, guided by the vague end-goal of plucking out my position from peanuts.\n\nI learned that the GPS signals that facilitate our mapping apps are ever-present, around us at any altitude, in any weather conditions, at all times.\n\nThis sounds cool in the abstract, but the tangible reality is staggering. These signals are all around me as I write this. They’re all around you as you read it. The world is soaked in these whispers, repeating themselves endlessly for anyone willing to listen.\n\nYou can find out exactly where you are, from thin air, anywhere at any time, by learning to speak the language of the electromagnetic waves flowing over your skin. These waves have been a constant and quiet companion for most people’s entire lives.\n\nGPS is perhaps one of the most audacious geo-engineering feats ever undertaken, and its traces can be felt with just an antenna and a motive.",
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