+raouljan Posted September 16, 2004 Share Posted September 16, 2004 How 'bout this..... The folks at GPS Central and the National Weather Service get together and download the current weather forecast via some of the unused bits in the data frame... then you can get the weather on your GPSr! And with the maping GPSr you could see the weater fronts, dry-line, etc. superimposed on the map! Quote Link to comment
+Lucanos Posted September 16, 2004 Share Posted September 16, 2004 Is there that much bandwidth left unused? Quote Link to comment
+raouljan Posted September 16, 2004 Author Share Posted September 16, 2004 Take a look at the signal format. It is basically a "super frame" configuration. http://gpsinformation.net/gpssignal.htm There are other documents out there with more detail ... some of the sub-frames appear to have free words. Since all the frames are transmitted (even the empty ones), yes .. it would appear that the bandwidth exists. Quote Link to comment
+BlueDeuce Posted September 16, 2004 Share Posted September 16, 2004 How 'bout this..... The folks at GPS Central and the National Weather Service get together and download the current weather forecast via some of the unused bits in the data frame... then you can get the weather on your GPSr! And with the maping GPSr you could see the weater fronts, dry-line, etc. superimposed on the map! I'd even take a static forecast, high temps, watches, flood alert area, etc, that you could upload everyday. A dynamic update would be sweet. You gonna mention it to them? Quote Link to comment
peter Posted September 16, 2004 Share Posted September 16, 2004 yes .. it would appear that the bandwidth exists. Bandwidth is indeed the issue. The total bit rate of the GPS signal is 50 bits/second and obviously most of that is required for sending the necessary clock, ephemeris , and almanac information. So even if you could free up 10% of the bandwidth for other purposes, that would only give you the ability to send about one character per second. That's like a very slow typist who can only manage 10 words/minute. People would need to keep their receivers on for extended periods of time with a good signal lock the whole time to get any significant amount of data. If you're moving you'd also expect to lose bits of the transmission fairly frequently as you get momentary signal losses from overhead tree limbs, bridges, buildings, etc. Quote Link to comment
+tirediron Posted September 16, 2004 Share Posted September 16, 2004 Ummm I would also point out that just because the documents don't tell you what is in a frame doesn't actually mean that it's empty! Who's the original customer of this service again? Quote Link to comment
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