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Current models for HH military hardware

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Re: Current models for HH military hardware
Post by munroburton   » Sun Apr 17, 2016 4:00 pm

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Weird Harold wrote:
jcreed57 wrote:Are we likely to see remotely-piloted LACs in HH's future?


RFC has expressly ruled any remote controlled or autonomous ships will NOT happen in the Honorverse.


Ships, no. But he already bent that rule into a pretzel when he armed recon drones in At All Costs. Then came Keyhole.

Autonomous in the Honorverse equals stupid. See Thunder of God in HotQ for an example - setting their EW systems to automatic left a hole big enough for a CA to kill a BC.

FTL comms made remote controlled combat crafts a little more plausible. About 62 times more, but this limits your drones to an operating radius of 18 million kilometres for a one-second delay. Any further than that and they start to become too unresponsive.

MDMs have far more range than that, so any drone command ship would have to expose itself to enemy fire anyway in order to effectively command its drones.

It would also need lots of FTL transmitter equipment, just like an Apollo salvo requires Keyhole platforms.

All that said, I don't see why that makes a drone variant of the Katana for screening duties impossible. Granted, they wouldn't be available for LAC hunting duties away from the wall/base - but you can keep manned versions around for that.
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Re: Current models for HH military hardware
Post by darrell   » Sun Apr 17, 2016 6:46 pm

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jcreed57 wrote:From a USNI press release:

"Navy, in addition to developing the railgun itself, is working on a hypervelocity projectile (HVP) that will support both the railgun and conventional 5-inch guns. The GPS-guided round will fly at hypersonic speeds, but the Navy is still working with the Pentagon’s Strategic Capabilities Office to close the fire control loop between the gun and the projectile."

So the load will have onboard guidance capability...and of course the mil-spec GPS systems are more accurate than civilian...I expect accuracy won't be that big of an issue. Of course, they could always illuminate the target for a laser-guided weapon using local human operatives or via low-power laser satellites. Actual sea-based laser weapons are nearing the 150-kW range, still a bit light for most uses.

Returning to the issue of strategy and doctrine, it would seem the current strike force centered around a carrier may be obsolete in favor of smaller, more agile, (and cheaper) ships that can project significantly more firepower in more flexible ways through the use of drones, railguns, and eventually lasers.


Prior to 1998 you would have been correct, but that is no longer true. In 1998 full GPS technology was declassified, and now the limit on accuracy is the complexity of the equipment and the number of satellites it triangulates from.

Basic GPS like in a cell phone triangulates from two satellites.

The next step up, like used in farming, triangulates from 4 satellites and is 10 times more expensive

Most military operations use GPS that triangulate from 6 satellites.

The most accurate GPS triangulate from 8 satellites. My dad works for a survey company, their CIVILIAN GPS survey gear is so accurate that the seldom use anything else. And no the company has never surveyed for the military, it is 99% surveying for construction companies in phoenix.
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Re: Current models for HH military hardware
Post by kzt   » Sun Apr 17, 2016 7:17 pm

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darrell wrote:Prior to 1998 you would have been correct, but that is no longer true. In 1998 full GPS technology was declassified, and now the limit on accuracy is the complexity of the equipment and the number of satellites it triangulates from.

No, P-code, M-code and MNAV are encrypted and you need a source of the crypto keys to use them.

There are an array of tools to improve the precision of GPS, like WAAS and differential GPS,that are used for precision applications like surveying and approaches for aircraft.
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Re: Current models for HH military hardware
Post by Relax   » Mon Apr 18, 2016 3:51 am

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darrell wrote:Basic GPS like in a cell phone triangulates from two satellites.

The next step up, like used in farming, triangulates from 4 satellites and is 10 times more expensive


To start with you cannot triangulate from 2 sources. Though technically, with the earth rotating at 1000mph or so, you sorta can and why there is a large difference between GPS signal accuracies. Better devices take this into account. Total number of satellites simply lets you RSS the error bands. For true 3d you need 4 satellites. Each quadrant only has 6 total and only 4 are operating at any single period of time, so you cannot even RSS the signals...

EDIT: Can see upwards of 10 and a low of 6 satellites at a time at extreme low angle, but their accuracy stinks. Low of 6 will have 4 operating with 2 held in reserve. So, it is possible to have 8 actually transmitting at once if one waits long enough.

What certainly is true, is a composite system using GLONASS and GPS should have better accuracy. I know there has been talk of using both, but that was back when GPS/GLONASS constellations were not complete. They are both complete now, so the need, is not present anymore.
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Re: Current models for HH military hardware
Post by darrell   » Mon Apr 18, 2016 7:46 am

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Relax wrote:
darrell wrote:Basic GPS like in a cell phone triangulates from two satellites.

The next step up, like used in farming, triangulates from 4 satellites and is 10 times more expensive


To start with you cannot triangulate from 2 sources. Though technically, with the earth rotating at 1000mph or so, you sorta can and why there is a large difference between GPS signal accuracies. Better devices take this into account. Total number of satellites simply lets you RSS the error bands. For true 3d you need 4 satellites. Each quadrant only has 6 total and only 4 are operating at any single period of time, so you cannot even RSS the signals...

EDIT: Can see upwards of 10 and a low of 6 satellites at a time at extreme low angle, but their accuracy stinks. Low of 6 will have 4 operating with 2 held in reserve. So, it is possible to have 8 actually transmitting at once if one waits long enough.

What certainly is true, is a composite system using GLONASS and GPS should have better accuracy. I know there has been talk of using both, but that was back when GPS/GLONASS constellations were not complete. They are both complete now, so the need, is not present anymore.

kzt wrote:No, P-code, M-code and MNAV are encrypted and you need a source of the crypto keys to use them.


GPS is not a simple bearing, it is a signal that includes a precision timestamp. Triangulate is a sloppy term, as a GPS dosen't figure versus angle. And yes, you only need 2 signals to determine location.

With each GPS signal, the timestamp gives a distance from a satellite at a known exact location.

To illustrate, you have a signal at 5,0 that is 3 units away from you. You have a second signal at 3,3 that is 2 units away from you. 2 signals at a known location and known distance, you are at 5,3.


Although P-code, M-code and MNAV are still encrypted, the encryptions are no longer classified, and full GPS data is available to anyone that wants it.

In order to decript the data at the source, we would need to launch a new full set of satalites, which is not cost effective. What was done was for the government to publish the decryption keys which made the data available to anyone that wanted to spend the money to get the key.

Computer machine code is still a code, but is available to anyone that wants to learn it. If the GPS codes were still classified, surveyors would still be using transits and Theodolite instead of GPS.
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Re: Current models for HH military hardware
Post by Vince   » Mon Apr 18, 2016 4:07 pm

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Even the military grade GPS data by itself is only accurate to about 10 meters or so. For most uses, that is all that is needed. But for extremely high precision needs like surveying, Differential GPS is used, which is accurate down to 10 centimeters.

See Differential GPS Explained
and
Differential GPS
for details.
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Re: Current models for HH military hardware
Post by darrell   » Mon Apr 18, 2016 7:57 pm

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Vince wrote:Even the military grade GPS data by itself is only accurate to about 10 meters or so. For most uses, that is all that is needed. But for extremely high precision needs like surveying, Differential GPS is used, which is accurate down to 10 centimeters.

See Differential GPS Explained
and
Differential GPS
for details.


the information that you are basing your assumptions on is about 20 years out of date. for example, current GPS surveying is now accurate to 1 CM horizontally and 2-3 CM vertically.

There is lots of applications in use today that needs to be a hell of a lot more accurate than even 1 meter.

Just one application: farming. Over the last 5 years most commercial farmers have been switching to GPS guided equipment because it is now more accurate than human driven equipment. The GPS equipment used in farming is good to less than 10 CM.
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Re: Current models for HH military hardware
Post by Grashtel   » Tue Apr 19, 2016 2:14 pm

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Relax wrote:What certainly is true, is a composite system using GLONASS and GPS should have better accuracy. I know there has been talk of using both, but that was back when GPS/GLONASS constellations were not complete. They are both complete now, so the need, is not present anymore.

Composite GPS/GLONASS systems are actually common now. The standard chipset used in the great majority of mobile phones (which are quite possibly the largest population of devices that use satellite navigation) is a composite system, it is more for reliability than accuracy as mobiles are used a lot in built up areas with poor views of the sky so having more satellites available improves the odds that there will be enough in view to get a solid fix
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Re: Current models for HH military hardware
Post by jcreed57   » Sat Apr 23, 2016 3:38 pm

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I'm seeing a lot of discussion regarding the accuracy of GPS within the three spatial dimensions...note should also be taken that the fourth dimension is also being refined, as timing gets more sophisticated.

I would imagine that by HH's time, with target speeds approaching C, timing would need to be accurate to within picoseconds...
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Re: Current models for HH military hardware
Post by kzt   » Sat Apr 23, 2016 6:26 pm

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Yeah, GPS elevation sucks compared to lat and lon. Baseline is too short due to the whole planet thing.
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