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Old 08-11-2017, 11:57 AM
cosmicfish cosmicfish is offline
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Quote:
Originally Posted by mmartin798 View Post
While I agree with you that more things arrived from the future that just a laser and fusion reactor, I have to disagree with you on the Autonav. Inertial Navigation Systems (INS) have been around since the 1960. By the time we get to the 1980s, there have been many advances in the types of gyros, the means to minimize drift errors and more, without the use of GPS. GPS is great when you have it, and I have little doubt that the Autonav does have GPS as one of it's inputs, but it can also use terrestrial radio signals, perhaps even private Morrow Industries eLoran towers. All of these receivers and sensors were quite small in the 1980s. None of this requires the use of 2020+ tech. Drift factors can be minimized by stopping the vehicle and letting the INS correct the velocity. When you are at a POI that is in the Autonav and you are stopped by it, you can completely reset the position. Plus the Autonav, for most purposes, just needs to be close enough. This is where I do drift from one of the books where it said something like the Autonav assured a first shot hit with the mortar I think. That just didn't seem plausible to me.
First, it is the accuracy of the autonav that is one the primary technical challenges to making it in the 80's - we've had inertial guidance since the 50's, the question is always how accurate it needs to be and for how long (between updates from a reference). If we downgrade the accuracy, we can make this in the 80's no problem... and the team will be lost within a day. The team has a few things going for it, like the fact that INS work better on ground vehicles than either air or water (since there is less slippage), but it also has to remain accurate for much, much longer between references than the average INS.

About those references... there will not be GPS. The US military works extensively on how to operate in a GPS-denied environment because any major war is going to see someone icing the constellations. There will not be any radio signals, Morrow or otherwise, during the period when most of the field teams start up. In particular, the Recon teams have to be able to operate for months without support, and that includes radio location services that would expose Morrow facilities. Want to guess what the error, relative and absolute, would be after a few months in a 1980's ground INS operating without GPS or other reference signals?

Yes, there are things you can do to accommodate these issues, but they are problematic - stopping every so often, revisiting reference points, these are all operational constraints that may be difficult to manage in many circumstances. And rebuilding the map is even trickier, you need to be able to register everything together, accommodate the errors, and then (eventually) reconcile your new map with anyone else's. Today, that kind of registration can take hours, even days, and that is for relatively small maps with the aid of powerful computers and staff for whom that is their job. Doing it on the fly in an MPV? Cumbersome, to say the least.

Second, there is more than just the INS in the autonav. There is also a computer containing a complete and detailed electronic map of the United States, cryptological gear, a milspec UI, and no doubt a few other interesting things I am not thinking about at the moment.

I am not an INS expert, but I work with the experts because INS is integral to the products I design. I would love to have something like the autonav now and I can't get it. So I'm having trouble believing that a strictly 1980's manufacturing line could spit one out using 1980's core technology based on some idea that it could be done. You couldn't make the iPhone in the 80's, you couldn't make the Model T in the civil war, and you couldn't make full steel plate armor in the bronze era just by going back in time with a plan for the item in question. They are all require improvements in underlying technologies and manufacturing tools. Technique and an interesting idea is not enough.
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