Ground Based Positioning System

[flatline]

In other threads, it has been made abundantly clear that folks think that a ground based positioning system is relatively easy to create and maintain. So I thought I'd start a thread to explore that idea a bit.

In order for a client to be able to determine its position in 2-D, it needs to be able to see a minimum of 3 beacons. To determine its position in 3-D, it needs to be able to see a minimum of 4 beacons. Better results are achieved as the number of visible beacons increases (with diminishing returns, but I think we can ignore that for now). This leads us to the concept of "beacon saturation" which describes the minimum number of beacons required such that a client in the covered area can see enough beacons to determine its position.

To get an idea of how many beacons are required, google for "radio line of sight calculator". You'll get lots of hits. I happen to like the calculator from http://www.calculatoredge.com, but they all basically do the same thing. Decide how high you expect the beacons' antennas to be and how high you expect the client's antenna to be to see just how far the client can be before the Earth blocks it's view of the beacon. This is a BEST CASE approximation since it ignores trees, buildings, atmospheric conditions, etc. Realistically, you'd probably choose to place more beacons closer together in order to get better coverage, allow client antennas to be lower, and make your network more tolerant of damage.

It may come as a surprise to some, but a 1000ft antenna's horizon is a mere 45 miles away, a 10,000ft antenna's horizon is 141 miles away, so building an antenna in each fortress city isn't going to work unless the antenna's are all tens of thousands of feet high. Note: These numbers are from calculatoredge's los calculator. Other calculators may yield slightly different results.

The higher the antenna, the greater the distance that a beacon can be seen, but at the same time, the harder it is to hide the antenna. Why does hiding an antenna matter? Well, because your enemies (and the type of person who delights in shooting rural stop signs) will probably attempt to destroy your beacons (or at least their antennas) so that your forces can't benefit from having reliable positioning information.

There are two easy ways for someone to find your beacon:
1. directional antenna can track a transmission back to its source. Very easy to do if the beacon is constantly broadcasting it's location (like current GPS networks). It becomes harder if the beacon only transmits when a client makes a request as long as the enemy can't fake requests.
2. spotting antennas by vision or radar.

#2 is the bigger problem unless you have a way of making your antennas invisible to sight and radar.

It seems like there are 2 obvious strategies for building out a GBPS:
1. Build few beacons that are very tall and well defended.
2. Build lots of cheap beacons that are not very tall, but can be close together.

I'm not going to explore these here, but I'm sure we will if this thread gets any traction.

--flatline

[Mack]

While a Line of Sight (LOS) system will certainly be more accurate, a Beyond LOS (BLOS) system may be good enough. Given the computing power of small devices today (not to mention what they are in Rifts) an error correction algorithm can compensate for a BLOS system's problems, especially the more time the algorithm has to calibrate.

As for implementation strategies, I'd go with both #1 and #2. Build large fixed towers wherever one already has a solid, defensible position. Then augment it with many smaller mobile ones. The more signals in play, the easier it is to reconcile one's position.

EDIT - And to toss some more "Rift-ness" into this, keep in mind that all Robot Vehicles have a 500 mile transmitter already in them, which allows large nations (CS, NGR, etc) to create a ton of signals to work with.

[eliakon]

You do realize that it is possible to broadcast beyond direct LOS?
One of the most common is bouncing signals off of the Ionosphere. Another is to use microsatellite debris to bounce signals off of.
Then there is the solution of simply having multiple airborne units that assist in this system

It would seem that the various long range radio systems in the game must use some sort of this system since they have nice ranges (many over a hundred miles) and don't come with multi-kilometer antenna.

Of course 'easy' and 'simple' are relative terms too.

Also as a side note...just how tall are those fortress cities again? (I could have sworn that Chi town was supposed to be something like two miles tall or some such)

[glitterboy2098]

https://en.wikipedia.org/wiki/Radio_navigation
https://en.wikipedia.org/wiki/Hyperbolic_navigation

https://en.wikipedia.org/wiki/LORAN
https://en.wikipedia.org/wiki/Loran-C
https://en.wikipedia.org/wiki/CHAYKA
https://en.wikipedia.org/wiki/Decca_Navigator_System
https://en.wikipedia.org/wiki/Gee_%28navigation%29
https://en.wikipedia.org/wiki/Alpha_%28navigation%29
https://en.wikipedia.org/wiki/Omega_%28 ... _system%29

if your using low frequency signals, you get over the horizon ability and require fewer stations. because with lower frequency signals, the atmosphere acts as a waveguide causing it to follow the curve of the earth. also gives it a degree of NLOS ability as well, since it won't always be blocked by mountains and such.

the downside is low frequency signals will be more susceptible to interference.

[flatline]

While a Line of Sight (LOS) system will certainly be more accurate, a Beyond LOS (BLOS) system may be good enough. Given the computing power of small devices today (not to mention what they are in Rifts) an error correction algorithm can compensate for a BLOS system's problems, especially the more time the algorithm has to calibrate.

Trilateralization assumes LOS signals. What algorithm are you proposing that can handle alternate path or multipath signals without knowing the exact paths used (which would require you to already know your position)?

[flatline]

Bouncing radio signals off the atmosphere/whatever is fine for communication because you don't care how the signal got there. However, if you want to use that signal to determine your position, it's going to cause all sorts of trouble since you're calculating the distance that the signal has traveled and assuming it's a straight line distance from the position that the beacon is advertising for itself which means your calculated position will be further from the beacon than it should be.

If you can see more beacons than you need, then it may be possible to recognize a non-LOS beacon and eliminate it from your set, but it's not a sure thing.

[flatline]

https://en.wikipedia.org/wiki/Radio_navigation
https://en.wikipedia.org/wiki/Hyperbolic_navigation

https://en.wikipedia.org/wiki/LORAN
https://en.wikipedia.org/wiki/Loran-C
https://en.wikipedia.org/wiki/CHAYKA
https://en.wikipedia.org/wiki/Decca_Navigator_System
https://en.wikipedia.org/wiki/Gee_%28navigation%29
https://en.wikipedia.org/wiki/Alpha_%28navigation%29
https://en.wikipedia.org/wiki/Omega_%28 ... _system%29

if your using low frequency signals, you get over the horizon ability and require fewer stations. because with lower frequency signals, the atmosphere acts as a waveguide causing it to follow the curve of the earth. also gives it a degree of NLOS ability as well, since it won't always be blocked by mountains and such.

the downside is low frequency signals will be more susceptible to interference.

If I understand the wikipedia articles, those are all examples of hyperbolic navigation. Only the Loran-C and CHAYKA (basically the same thing) can get accuracy less than hundreds of meters. What are the theoretical limits? Could accuracy be made good enough to use such a system to target missiles or artillery?

[Mack]

While a Line of Sight (LOS) system will certainly be more accurate, a Beyond LOS (BLOS) system may be good enough. Given the computing power of small devices today (not to mention what they are in Rifts) an error correction algorithm can compensate for a BLOS system's problems, especially the more time the algorithm has to calibrate.

Trilateralization assumes LOS signals. What algorithm are you proposing that can handle alternate path or multipath signals without knowing the exact paths used

An advanced one. After all, we are talking about nations that crank out robot vehicle armies.

For starters one should use at least 4 signals because we have to solve for time as well as all three dimensions. (This is standard for today's GPS system.) Also, this is why I advocate for a lot of signals... every added one makes the location easier/faster to find.

(which would require you to already know your position)?

Keep in mind the context. How often would the equipment operator turn on the equipment for the first time and NOT know he's in western Iowa?

[flatline]

I'll read up more on these hyperbolic navigation systems. Measuring deviation in signal phase still assumes no alternate path or multi-path issues, but being able to use frequencies that predictably "bend" around the surface of the earth makes that a non-issue (or at least much less of an issue).

Can an antenna on the ground receive these signals or does a non-LOS receiver need to be pretty high up to receive signals that have come over the horizon?

[Jefffar]

In WW2 there were ground based beacons used to provide navigational aides to aircraft and ships. Some of them were even used to provide a cross referenced positioning fix for dropping bombs on target. Updated versions were used in bombing raids during the Vietnam War.

If such things were doable then, when navigators had to manually plot their position using compasses and slide rules, it should be doable with greater accuracy in Rifts.

[drewkitty ~..~]

There is already something like this in the rifters already for Rifts.

[Alrik Vas]

Which rifter?

[flatline]

Okay, I've had a chance to look into the different hyperbolic positioning schemes. Pretty elegant math, but trivial for an enemy with modern radio equipment (as opposed to Rifts tech) to totally ruin it. Simply set up a transceiver that receives the initial signal and then concurrently rebroadcasts multiple copies of the signal all with different phase shifts.

The client will receive the initial pulse, but won't be able to distinguish the true secondary pulse from all the fake pulses being broadcast by the enemy. The only real constraint is that the enemy transmitter needs to be closer to your client than the secondary transmitter is to the primary transmitter (but that's easy to do since your transmitters need to be relatively far apart for the hyperbolic positioning scheme to work in the first place).

I'm uncertain if encryption could be used to "sign" the secondary pulse. Wikipedia seems to indicate that the primary and secondary pulses are identical, but I didn't see that stated as a requirement. If the pulses can be different, then the enemy would need to repeat the secondary pulse instead of the first which means the enemy transceiver would need to be either between the client and the secondary transmitter or close enough to the client that the true secondary pulse and the fake secondary pulses can't be separated via timing analysis. The lower the frequency used, the easier this becomes for the enemy. But using a higher frequency gives up the non-LOS benefits of this scheme, so I think you're stuck.

Worst case, the enemy simply broadcasts noise after the primary pulse is received to prevent the secondary pulse from being analyzable. In which case you'd treat it like any other jammer and try to destroy it with a HARM missile (or Rifts equivalent).

[Riftmaker]

I'm surprised no one has brought up the magic issue yet. How's any of this work with lay lines and magic involved.

[Mack]

I'm surprised no one has brought up the magic issue yet. How's any of this work with lay lines and magic involved.

With the notable exception of the Frequency Jamming spell, I don't see where magic has any effect at all.

[flatline]

Do magnetic compasses work reliably on Rifts Earth?

Do they work at all on or near ley lines?

[Mack]

Do magnetic compasses work reliably on Rifts Earth?

Do they work at all on or near ley lines?

Is there anything that says they don't?

(I tend to work on the premise that unless something in canon changes it, then nature and natural phenomenon is unchanged.)

[Alrik Vas]

How powerful of a jamming signal would you need? And straight up white noise ruins the jammer's radio based systems as well. Most forces use radio communication.

[eliakon]

Okay, I've had a chance to look into the different hyperbolic positioning schemes. Pretty elegant math, but trivial for an enemy with modern radio equipment (as opposed to Rifts tech) to totally ruin it. Simply set up a transceiver that receives the initial signal and then concurrently rebroadcasts multiple copies of the signal all with different phase shifts.

The client will receive the initial pulse, but won't be able to distinguish the true secondary pulse from all the fake pulses being broadcast by the enemy. The only real constraint is that the enemy transmitter needs to be closer to your client than the secondary transmitter is to the primary transmitter (but that's easy to do since your transmitters need to be relatively far apart for the hyperbolic positioning scheme to work in the first place).

I'm uncertain if encryption could be used to "sign" the secondary pulse. Wikipedia seems to indicate that the primary and secondary pulses are identical, but I didn't see that stated as a requirement. If the pulses can be different, then the enemy would need to repeat the secondary pulse instead of the first which means the enemy transceiver would need to be either between the client and the secondary transmitter or close enough to the client that the true secondary pulse and the fake secondary pulses can't be separated via timing analysis. The lower the frequency used, the easier this becomes for the enemy. But using a higher frequency gives up the non-LOS benefits of this scheme, so I think you're stuck.

Worst case, the enemy simply broadcasts noise after the primary pulse is received to prevent the secondary pulse from being analyzable. In which case you'd treat it like any other jammer and try to destroy it with a HARM missile (or Rifts equivalent).

Yes you can encrypt the signals, that is what real world militaries do when they do this.
and speed of light makes it hard to intercept a signal, read it, and generate a new one before the old one gets to the person.
Especially if you don't have the ability to put the correct digital 'signature' on the signal
Now yeah, if you have the ability to reliably jam an entire continents radios sure.....
But I think that is a bit out of most peoples budgets.
There is a reason that the real world versions of these systems were not 'trivial' to render ineffective. Since the real world LORAN system was used up into the 80s (and did not have the luxury of thousands of cheap 500mi range encrypted radio stations like rifts does) I am going to suspect that it was probably seen as effective and difficult enough to tamper with to be useful for the Navy.

[flatline]

Okay, I've had a chance to look into the different hyperbolic positioning schemes. Pretty elegant math, but trivial for an enemy with modern radio equipment (as opposed to Rifts tech) to totally ruin it. Simply set up a transceiver that receives the initial signal and then concurrently rebroadcasts multiple copies of the signal all with different phase shifts.

The client will receive the initial pulse, but won't be able to distinguish the true secondary pulse from all the fake pulses being broadcast by the enemy. The only real constraint is that the enemy transmitter needs to be closer to your client than the secondary transmitter is to the primary transmitter (but that's easy to do since your transmitters need to be relatively far apart for the hyperbolic positioning scheme to work in the first place).

I'm uncertain if encryption could be used to "sign" the secondary pulse. Wikipedia seems to indicate that the primary and secondary pulses are identical, but I didn't see that stated as a requirement. If the pulses can be different, then the enemy would need to repeat the secondary pulse instead of the first which means the enemy transceiver would need to be either between the client and the secondary transmitter or close enough to the client that the true secondary pulse and the fake secondary pulses can't be separated via timing analysis. The lower the frequency used, the easier this becomes for the enemy. But using a higher frequency gives up the non-LOS benefits of this scheme, so I think you're stuck.

Worst case, the enemy simply broadcasts noise after the primary pulse is received to prevent the secondary pulse from being analyzable. In which case you'd treat it like any other jammer and try to destroy it with a HARM missile (or Rifts equivalent).

Yes you can encrypt the signals, that is what real world militaries do when they do this.
and speed of light makes it hard to intercept a signal, read it, and generate a new one before the old one gets to the person.
Especially if you don't have the ability to put the correct digital 'signature' on the signal
Now yeah, if you have the ability to reliably jam an entire continents radios sure.....
But I think that is a bit out of most peoples budgets.
There is a reason that the real world versions of these systems were not 'trivial' to render ineffective. Since the real world LORAN system was used up into the 80s (and did not have the luxury of thousands of cheap 500mi range encrypted radio stations like rifts does) I am going to suspect that it was probably seen as effective and difficult enough to tamper with to be useful for the Navy.

You misunderstood. The signal travels at the speed of light, but it takes several wavelengths of the frequency to transmit. If the enemy starts repeating the signal as soon as they receive it, but at a different phase, then the fake signals will have the correct signature but be sufficiently overlapping with the true
signal to make it difficult for the client to know which signal to use. I'm assuming that the client is sophisticated enough to recognize there are several overlapping pulses. A less sophisticated client would just see a bunch of noise (aka "jammed").

[eliakon]

Okay, I've had a chance to look into the different hyperbolic positioning schemes. Pretty elegant math, but trivial for an enemy with modern radio equipment (as opposed to Rifts tech) to totally ruin it. Simply set up a transceiver that receives the initial signal and then concurrently rebroadcasts multiple copies of the signal all with different phase shifts.

The client will receive the initial pulse, but won't be able to distinguish the true secondary pulse from all the fake pulses being broadcast by the enemy. The only real constraint is that the enemy transmitter needs to be closer to your client than the secondary transmitter is to the primary transmitter (but that's easy to do since your transmitters need to be relatively far apart for the hyperbolic positioning scheme to work in the first place).

I'm uncertain if encryption could be used to "sign" the secondary pulse. Wikipedia seems to indicate that the primary and secondary pulses are identical, but I didn't see that stated as a requirement. If the pulses can be different, then the enemy would need to repeat the secondary pulse instead of the first which means the enemy transceiver would need to be either between the client and the secondary transmitter or close enough to the client that the true secondary pulse and the fake secondary pulses can't be separated via timing analysis. The lower the frequency used, the easier this becomes for the enemy. But using a higher frequency gives up the non-LOS benefits of this scheme, so I think you're stuck.

Worst case, the enemy simply broadcasts noise after the primary pulse is received to prevent the secondary pulse from being analyzable. In which case you'd treat it like any other jammer and try to destroy it with a HARM missile (or Rifts equivalent).

Yes you can encrypt the signals, that is what real world militaries do when they do this.
and speed of light makes it hard to intercept a signal, read it, and generate a new one before the old one gets to the person.
Especially if you don't have the ability to put the correct digital 'signature' on the signal
Now yeah, if you have the ability to reliably jam an entire continents radios sure.....
But I think that is a bit out of most peoples budgets.
There is a reason that the real world versions of these systems were not 'trivial' to render ineffective. Since the real world LORAN system was used up into the 80s (and did not have the luxury of thousands of cheap 500mi range encrypted radio stations like rifts does) I am going to suspect that it was probably seen as effective and difficult enough to tamper with to be useful for the Navy.

You misunderstood. The signal travels at the speed of light, but it takes several wavelengths of the frequency to transmit. If the enemy starts repeating the signal as soon as they receive it, but at a different phase, then the fake signals will have the correct signature but be sufficiently overlapping with the true
signal to make it difficult for the client to know which signal to use. I'm assuming that the client is sophisticated enough to recognize there are several overlapping pulses. A less sophisticated client would just see a bunch of noise (aka "jammed").

Yeah....
I will admit that I was not an EWO, but if it was really this easy to do....
....people would have done it, and would still do it to the various current radio positioning systems (aka GPS)
I am not saying that it might not be possible to interfere with such a system. But I suspect that it would require lots of advanced equipment being run by highly trained personal (At the very least we are looking at possessing the Electronics Warfare skill) which to me sounds like the opposite of 'trivial'
Doable? Maybe. But if we rule out everything that is doable........

[Riftmaker]

I'm surprised no one has brought up the magic issue yet. How's any of this work with lay lines and magic involved.

With the notable exception of the Frequency Jamming spell, I don't see where magic has any effect at all.

I could have sworn laylines screwed with long range radios.

[glitterboy2098]

that's something lots of people "remember" but no one can seem to actually find in the books.

[flatline]

GPS jamming is alarmingly simple. All it takes is ordering the right piece of equipment off the internet and flipping the power switch. Just like a cell phone jammer. It's so easily available that one of the hardware vendors we work with has added a "feature" to alert us when one of our devices is in an area where GPS is being actively jammed.

Was LORAN-C vulnerable to the kinds of attacks I speculated about above? Maybe. Modern HAM radios can do the kinds of things I've suggested and there's no telling how long the military has had the capability. Perhaps that's the real reason they shut it down rather than keep it as a backup to GPS like the Coast Guard wanted. If I had to guess, I'd say that analog radios couldn't perform the kinds of attacks I've described (or could but were too expensive) which probably means that LORAN-C was safe until the age of digital signal processing for the common man. But that's just a guess. Maybe simply having oceans between us and our enemies did more to protect LORAN-C than any limitations of analog radio technology.

Rifts Earth is a far more hostile environment and we're all assuming that the technology is far advanced over what we can do today. The CS certainly has the technology to build a functional GBPS, but at the same time, some of their enemies are similarly advanced and, perhaps, have counters for such a thing. My primary objection to a GBPS that extends beyond CS borders is that for all the effort and expense required to make it work, it's likely that it can be locally defeated with very little effort. As such, I would expect the CS to instead use non RF positioning systems like taking pictures of the sky (cameras can still see stars during the day with proper filtering) and determining position based on what stars are "visible" or something similar, perhaps combined with gyroscopes and dead reckoning systems like what modern submarines use today. Heck, maybe in Rifts, all that will fit on a chip.

The point of this thread is that I'm uncomfortable assuming that something will just work. I want to examine the possibilities from both sides before I decide what to include in my version of the setting. If the CS could reliably send a missile to any target in North America without needing a spotter nearby, then they wouldn't need the extensive military they have now, so what's preventing it? Maybe it's because without satellites, they can't build a reliable long range positioning system (hence, this thread).

In my own setting, the skies are dangerous. If you fire a missile at something 500 miles away, it will probably be destroyed before it gets there. If I had another explanation, I could relax that rule a bit and make air travel a little easier.

[drewkitty ~..~]

Which rifter?

Rifter 42, pages 47-49. The article they are in runs from page 45-67.

[eliakon]

GPS jamming is alarmingly simple. All it takes is ordering the right piece of equipment off the internet and flipping the power switch. Just like a cell phone jammer. It's so easily available that one of the hardware vendors we work with has added a "feature" to alert us when one of our devices is in an area where GPS is being actively jammed.

Was LORAN-C vulnerable to the kinds of attacks I speculated about above? Maybe. Modern HAM radios can do the kinds of things I've suggested and there's no telling how long the military has had the capability. Perhaps that's the real reason they shut it down rather than keep it as a backup to GPS like the Coast Guard wanted. If I had to guess, I'd say that analog radios couldn't perform the kinds of attacks I've described (or could but were too expensive) which probably means that LORAN-C was safe until the age of digital signal processing for the common man. But that's just a guess. Maybe simply having oceans between us and our enemies did more to protect LORAN-C than any limitations of analog radio technology.

Rifts Earth is a far more hostile environment and we're all assuming that the technology is far advanced over what we can do today. The CS certainly has the technology to build a functional GBPS, but at the same time, some of their enemies are similarly advanced and, perhaps, have counters for such a thing. My primary objection to a GBPS that extends beyond CS borders is that for all the effort and expense required to make it work, it's likely that it can be locally defeated with very little effort. As such, I would expect the CS to instead use non RF positioning systems like taking pictures of the sky (cameras can still see stars during the day with proper filtering) and determining position based on what stars are "visible" or something similar, perhaps combined with gyroscopes and dead reckoning systems like what modern submarines use today. Heck, maybe in Rifts, all that will fit on a chip.

The point of this thread is that I'm uncomfortable assuming that something will just work. I want to examine the possibilities from both sides before I decide what to include in my version of the setting. If the CS could reliably send a missile to any target in North America without needing a spotter nearby, then they wouldn't need the extensive military they have now, so what's preventing it? Maybe it's because without satellites, they can't build a reliable long range positioning system (hence, this thread).

In my own setting, the skies are dangerous. If you fire a missile at something 500 miles away, it will probably be destroyed before it gets there. If I had another explanation, I could relax that rule a bit and make air travel a little easier.

I guess it comes down to deciding what your comfortable with.
I am uncomfortable with assuming that something will just not work, you are uncomfortable with assuming that it will.
Neither is right or wrong, just different. Both look at different parts of the system, different backgrounds and more importantly different personal views on their game worlds and come to different views on what can or can not, should or should not work.

[Alrik Vas]

I'd just siembieda it.

Works until a PC successfully uses jamming gear at -20%.

[SpiritInterface]

All you need is an accurate clock, a camera and good computer with the right software and database, to calculate where you are.

[kaid]

https://en.wikipedia.org/wiki/Radio_navigation
https://en.wikipedia.org/wiki/Hyperbolic_navigation

https://en.wikipedia.org/wiki/LORAN
https://en.wikipedia.org/wiki/Loran-C
https://en.wikipedia.org/wiki/CHAYKA
https://en.wikipedia.org/wiki/Decca_Navigator_System
https://en.wikipedia.org/wiki/Gee_%28navigation%29
https://en.wikipedia.org/wiki/Alpha_%28navigation%29
https://en.wikipedia.org/wiki/Omega_%28 ... _system%29

if your using low frequency signals, you get over the horizon ability and require fewer stations. because with lower frequency signals, the atmosphere acts as a waveguide causing it to follow the curve of the earth. also gives it a degree of NLOS ability as well, since it won't always be blocked by mountains and such.

the downside is low frequency signals will be more susceptible to interference.

Yup thats about what I was thinking as well the old style loran navigation systems. Basic range of about 1500 miles accuracy decent enough to figure your location to within a few miles. The only thing we don't know is what if any effect would ley line activity have on this kind of traffic.

[flatline]

https://en.wikipedia.org/wiki/Radio_navigation
https://en.wikipedia.org/wiki/Hyperbolic_navigation

https://en.wikipedia.org/wiki/LORAN
https://en.wikipedia.org/wiki/Loran-C
https://en.wikipedia.org/wiki/CHAYKA
https://en.wikipedia.org/wiki/Decca_Navigator_System
https://en.wikipedia.org/wiki/Gee_%28navigation%29
https://en.wikipedia.org/wiki/Alpha_%28navigation%29
https://en.wikipedia.org/wiki/Omega_%28 ... _system%29

if your using low frequency signals, you get over the horizon ability and require fewer stations. because with lower frequency signals, the atmosphere acts as a waveguide causing it to follow the curve of the earth. also gives it a degree of NLOS ability as well, since it won't always be blocked by mountains and such.

the downside is low frequency signals will be more susceptible to interference.

Yup thats about what I was thinking as well the old style loran navigation systems. Basic range of about 1500 miles accuracy decent enough to figure your location to within a few miles. The only thing we don't know is what if any effect would ley line activity have on this kind of traffic.

Good enough to get close to something, but not good enough to guide a long range missile to particular target coordinates. Some method would still be required for the missile to make course corrections as it approaches the target like a spotter on the ground or perhaps accompanying aircraft to paint the target with a laser.

[eliakon]

https://en.wikipedia.org/wiki/Radio_navigation
https://en.wikipedia.org/wiki/Hyperbolic_navigation

https://en.wikipedia.org/wiki/LORAN
https://en.wikipedia.org/wiki/Loran-C
https://en.wikipedia.org/wiki/CHAYKA
https://en.wikipedia.org/wiki/Decca_Navigator_System
https://en.wikipedia.org/wiki/Gee_%28navigation%29
https://en.wikipedia.org/wiki/Alpha_%28navigation%29
https://en.wikipedia.org/wiki/Omega_%28 ... _system%29

if your using low frequency signals, you get over the horizon ability and require fewer stations. because with lower frequency signals, the atmosphere acts as a waveguide causing it to follow the curve of the earth. also gives it a degree of NLOS ability as well, since it won't always be blocked by mountains and such.

the downside is low frequency signals will be more susceptible to interference.

Yup thats about what I was thinking as well the old style loran navigation systems. Basic range of about 1500 miles accuracy decent enough to figure your location to within a few miles. The only thing we don't know is what if any effect would ley line activity have on this kind of traffic.

Good enough to get close to something, but not good enough to guide a long range missile to particular target coordinates. Some method would still be required for the missile to make course corrections as it approaches the target like a spotter on the ground or perhaps accompanying aircraft to paint the target with a laser.

Or maybe it self guides in optically from there?

[Jefffar]

Odd thought - if ley lines interfere with radio waves to some degree (as been speculated) or at least can be detected, couldn't they form the basis for a positioning system?

[flatline]

Odd thought - if ley lines interfere with radio waves to some degree (as been speculated) or at least can be detected, couldn't they form the basis for a positioning system?

If they remain constant (enough) and can be detected reliably, sure. Any non-transient feature of the environment could, in theory, be used to help you determine your position. That's how maps work, for instance.

[flatline]

https://en.wikipedia.org/wiki/Radio_navigation
https://en.wikipedia.org/wiki/Hyperbolic_navigation

https://en.wikipedia.org/wiki/LORAN
https://en.wikipedia.org/wiki/Loran-C
https://en.wikipedia.org/wiki/CHAYKA
https://en.wikipedia.org/wiki/Decca_Navigator_System
https://en.wikipedia.org/wiki/Gee_%28navigation%29
https://en.wikipedia.org/wiki/Alpha_%28navigation%29
https://en.wikipedia.org/wiki/Omega_%28 ... _system%29

if your using low frequency signals, you get over the horizon ability and require fewer stations. because with lower frequency signals, the atmosphere acts as a waveguide causing it to follow the curve of the earth. also gives it a degree of NLOS ability as well, since it won't always be blocked by mountains and such.

the downside is low frequency signals will be more susceptible to interference.

Yup thats about what I was thinking as well the old style loran navigation systems. Basic range of about 1500 miles accuracy decent enough to figure your location to within a few miles. The only thing we don't know is what if any effect would ley line activity have on this kind of traffic.

Good enough to get close to something, but not good enough to guide a long range missile to particular target coordinates. Some method would still be required for the missile to make course corrections as it approaches the target like a spotter on the ground or perhaps accompanying aircraft to paint the target with a laser.

Or maybe it self guides in optically from there?

It's too bad we don't have any description of the sensor suite installed on the various missiles.

[Alrik Vas]

Okay, so could you have varying layers of encrypted communication between points that change what is primary and secondary based on interference (weather, jamming, scrambling, etc)?

Basically, real time positioning is made the normal way if using three points. If the signal is jammed, the firing unit just uses a map triangulation if terrain from location to target is readable?

You could also use laser communications from drones and other aircraft, which could use something like oir ARGUS to make the maps in real time?

[Mack]

The point of this thread is that I'm uncomfortable assuming that something will just work. I want to examine the possibilities from both sides before I decide what to include in my version of the setting. If the CS could reliably send a missile to any target in North America without needing a spotter nearby, then they wouldn't need the extensive military they have now, so what's preventing it? Maybe it's because without satellites, they can't build a reliable long range positioning system (hence, this thread).

For my part in this discussion, I never intended to imply that the CS (or NGR, or Archie...) could build a system to cover the entire continent. Just cover their own territory plus some reasonable distance beyond their borders (100 miles? 250 miles?). This would be one aspect of why it's difficult for opponents to operate within CS/NGR/Archie territory.

[Nox Equites]

that's something lots of people "remember" but no one can seem to actually find in the books.

I think it is a side effect of Leyline Storms, but not an ever present effect. Even a heavy electrical storm might interfere with the radios.

[Blue_Lion]

Do we not have navigation systems for air craft that do not require position services. A combination of gyroscopic(direction)navigation and speed system can guide a missile.

If I recall the part about ley lines radiating energy is pre RUE think the original rifts book or Atlantis will do some research if I get time.

Giving risks of rifts earth weather or not it is feasible to maintain such a system may be subject to debatable. There are however lots of ways to navigate with sensors that do not require it.

Part of it may come down to how often is long range travel done that requires it. CS navy seams to say most major CS mass transport of goods use rivers. Such transports would not really require the use of such a system to reach the goal or even know where they are. So there will be a lack of civilian use from CS. Most long range CS military operations may want such a system but how much of a risk is involved in the use of them. Most troops are grunts with limited tech skills so ECW may pose a risk of friendly fire. Most forces have missiles that can be shot set to chance the signal so risk of constant fire attack.

NG and bandito would be the ones in north America with the most to gain from such systems. They would have the most long range transport and would need to send stuff all over what half the US. Bandito uses allot of transport robots that could navigate blind giving that they do not want to advertise there presence they would not likely maintain such a system. That makes the most likely backer NG.

So it comes down to would NG devote resources to such a system when they do have other navigation methods available to them.

So to me it comes down to comparing the strengths of such a system vs other systems that could or do exist in the setting.
Strengths of a positioning system are.
Easy to use.
Can find your location when lost.

Its dependence on transmitters being available means.
Weakness include subject to electronic warfare. (Broad spectrum jamming can be set up to block this system as well as the enemies main radio lines. Great way to cripple large units movements.)
Transmitters are a easy to find target. (Can't hide a base with such system)
Some types of position systems the device navigating gives off its location.