Information is the life blood of modern combat which by necessity is being made even more important as the range and destructive power of modern weapons continues to increases faster than our ability to precisely control them. With every increase in range comes the added number of possible friendly or neutral entities becoming intended targets, (friendly fire, bitter-sweet conflicts). The range of many modern weapons, are already greater than the current capacity to reliably classify, identify, and to properly target our current weapons. The amount, quality, and reliability of the information you posses to make sound decisions while at the same time denying to your potential adversary information he needs will determine the outcome of most future engagements. It is not the destructive power or even the speed of your weapons that will be the determining factor. In most cases adequate quantity and quality of information will often determine if engagements are to occur at all or if the use of destructive force is even an acceptable option. The only way too effectively use the power of these weapons is in the application of the strategy called Cover and Deception.
The control of the electromagnetic spectrum, both for your use and to deny its use to the enemy is at the heart of all aspects Electronic Warfare. Any method, ether by the use of tactics or technology that reduces the quality, power, duration, or frequency of energy emissions employed by active sensors or coincidental energy releases of your systems ether for detection, identification, navigation, propulsion, or communication, reduces the amount and quality of an adversary’s available information which then cannot be used against you. This lack of information to a possible adversary complicates and lengthens their decision making loop and severely decreases his number of safe options. Likewise anything that increases your situational information by merging passively obtained emitted energies, (including sound), is a plus. There is now a technology available that can allow us to do decrees our energy emissions and increases our situational awareness at the same time.
As reported in July/August issue of Defense Technology International magazine, MIT Lincoln Laboratory has produced an IR laser data link with 100 gigabit capacity (I am assuming that they mean 100 gigabits per second capacity) for use in airborne systems. It is intended to download complete data files and raw sensor data in real-time to ground stations for analysis from airborne surveillance drones. The very large data files coming from various airborne sensors are today too large for easy on-board storage, or when they are stored for later delivery they often incur disadvantaged in their utility because of lack of timeliness, and if stored they must then be so compresses that they may lose valuable data. This lightweight device is said to work at ranges up to 40 miles. There are other better uses for this type of capacity as I will try to demonstrate. These new demonstrated abilities can change most of what we now think we know of how to conduct modern warfare.
Up to now military data links have been exclusively used for the transfer of processed data in symbolic form. That is, even when these systems are working at their best, all you get is somebody’s best guess of what is going on based upon their limited sensors that they are sufficiently interested in, on their end of the tactical picture, to inter into the system. If you are operating at the other end of this link you may be lucky to get anything tactically useful to you? Remember, that guys working on the other end whom must do all the work of entering and updating information into the system will only enter what he thinks is important based upon his priorities.
I will not get into all the issues that are evolved just in the mechanics of transferring processed data across various systems, platforms, frequencies, formats, and the time delay issues deriving from the communication links themselves, all of which were originally designed for other tasks and then were later adapted towards the current network centric pyridine on informational warfare. It would make your head swim.
Now it has become possible by using this new technology, (based upon high capacity IR laser data links) to implement a new form of information transfer within real time tactical situations, changing once again, the current network centric pyridine. The easiest and quickest place to implement this new capacity is between already existing compatible systems. The first obvious application well be in the combined operations of naval task-forces.
By utilizing already existing platforms containing identical equipment, a new enhanced functionality of a kind never before seen in warfare is now possible. The availability of a extremely high bandwidth real time data streams, implemented in the form of a tight two way secure beams of very difficult to detect out of boar-sight light, used within the line of sight can besides transferring huge amounts of data of types which are already being transferred by less secure and slower means, it can also be used in completely new ways to get never before seen capacities.
As a natural by product of laser data link’s intrinsic operation, the equipment will simultaneously and continually plot the exact relative ranges and bearings between all the linked units to within a fraction of a meter and can set a time synchronization standard between all the various systems to a level of less then a few micro-seconds, even without the assistance of an external time standard like GPS, and perhaps even far better. These features will become crucial to the discussion later when we talk about the issues that impact upon time and wavelength.
These capacities make it possible to now combine more than just symbolic knowledge (icons on a computer screen and some associated script but raw uncompressed sensor data). Sensor data from identical systems operating from dispersed physical locations that can be formed into synthetic virtual sensor array of great size and power. These synthetic virtual arrays can create a far more powerful and complete picture of the situational awareness in a large geographic area than has ever been before possible while at the same time reducing the number of tattle-tail energy emissions that reveal the locations and composition of the task-force.
I will use as my example a simple case of just three Arieighs Burke flight II destroyers sailing together in a typical task-force screening formation and just a few of the possible synergies that can be obtained when their combat sensor system’s raw sensor data are virtually merged. We will use in this example the AN/SPY-1D Radar of the Aegis weapon system, AN/SLQ-32 (v3) the ESM section of that countermeasures suite, and parts of the AN/SQQ-89 sonar suite (composed of the AN/SQQ-53C Hull Mounted Sonar, AN/SQR-19 Towed Array Sonar, AN/SQQ-28 LAMPS MK II Sonobuoy Processing System, and the ASWCS MK116 MOD 7 Anti-Submarine Warfare Control System.
We will first take the easiest application for novices unfamiliar with the concepts of data merging to understand. That of real time raw data sharing of ESM (electronic support measures) intercepts. Something that has been done for many years by dedicated ground stations to good effect. ESM intercepts, ether threats correctly identified and properly filtered or not, often get shorted out of the command loop decision making process because unless the intercepted signal indicates that it, a jet or missile, is coming strait down your throat to possibly kill you, they do not give the shouter much usable information or a usable target. A bearing line is not a plot and gives decision makers too little useful information and thus he or she will prefer other means of verifying the possible threat. If a signal's origin is beyond the horizon and not discernible by other means, the commander if he or she is sufficiently concerned by the ESM report will launch something like a helicopter to validate it and in so doing, will give away their own position and capacities.
There are four ways of locating an emitter passively,( amplitude, phase, time of arrival, and Doppler) two are practical to use with the equipment under discussion, one of these is triangulation DF based upon signal strength (amplitude) and the other is by measuring the time of arrival using three or more dispersed receivers taking some definable RF signal feature, like Chirp as a time point.
At present triangulation DF is possible only within some critical operational frequencies, though it is, I am sorry to say, seldom used to its full potential. It is done by using processed data through the NTDS (Naval Tactical Data System) system. But the precise DF capacity of the ship’s equipment, both to the degree of the equipments DF accuracy, speed of acquisition, and in the frequencies available are quite limited. This is mainly due to the required antennas size needed for DF analyses using the signal strength method for many of the most useful lower frequencies. Topmast space for antennas of any kind is always at a high premium on warships.
I do not know of any combat ship that has DF capacity RF in the HF, VHF or UHF bands. The VHF and UHF bands are used extensively by both small and medium size surface craft of both civilian and military use, and they are used universally by aircraft. I have on occasion even seen submarines do a quick pop up for just long enough to give a (shout out) from time to time. They do so like bragging about their success in getting away from the surface guys. They can do this with impunity because they know that tactical units, (not shore based intercept stations), do not have DF capacity in these RF ranges. Usually submariners are the supreme masters in the use of all aspects of Cover and Deception but they can be arrogant at times.
The signals of these frequencies travel far beyond the radar horizon. The time of arrival method of locating both commutations and navigation emissions can be done quite easily if you have the time domain and the space domain between the receiving units very well defined (a few inches and micro-seconds). This triangulation technique can not only be used to plot instantaneous positions by use of RF ground waves but just as the use of continues plots have been used in conventional radar, consecutive plots of this kind can give you the approximate course and speed as well as location of these emitters. Think about what that means to the task-force commander when the task force is operating in emission silence mode (Com-Con) and how much more attractive to the commander it would be to operate in that mode if this kind of information is available for free?
Now let us consider the sonar suite. First the AN/SQR-19 Towed Array Sonar is already, (as it is physically constructed and used), a true synthetic array, where the signal processing techniques of beamforming and intereromerty are used to combine the outputs from the many and various passive hydrophones along the string into one result. The more electronically combined signals added from additional sensors, increase the over all sensitivity of the systems (its detection and identification ability). Added together above that of the individual ship’s abilities and provides better source directionally. By combing the signal outputs of the three separated AN/SQR-19’s together not only do you get a far better directionally coming from their different locations, perhaps rising to the level of getting instantaneous three-dimensional plots, but it will have (as a system), better total overall system sensitivity in finding and identifying targets initially. To do all these wonderful things, all that is required is to connect the systems through the real time data link of sufficient bandwidth, add additional computing power (cheaper every day they like to say in silicon valley), and create some additional computer code. A real no brainier if you ask me.
You can do the similar thing with the AN/SQQ-53C Hull Mounted Sonar system but in this case the real advantage is that just one ship within the task-force can go sonar active (perhaps operating at its full power) while the other ship’s in the task-force systems remain passive. In so doing the passive ships will not have to give away their positions or if they have already been detected and tracked by a submarine, they may not have necessarily been identified as to their hull type and just what function within the taskforce they are serving. From the Submarine’s point of view, the question they must always ask themselves; who out there could be the shooter? In fact, if the submarine happens to be physically closer to one of the passive units, than it is to the active sonar radiating ship, the passive ship may get a stronger return (depending of relative aspect ratio to the source and sound propagation conditions) from the sub than that which the active ship receives and hence it gets a better targeting solution without completely giving itself away.
Now for the hardest test of this concept, the AN/SPY-1D Radar of the Aegis weapon system. The difficulty of combining the information from different propagating wave fronts, collaterally received at different locations, is proportionally more difficult with the increase in frequency utilized by the sensor system and with the corresponding decrease in the wavelength of those systems, (time and distance measurement). Sound waves are much easier to combine than microwaves. So easy that it can be easily done within the analog domain but it can and has successfully been done in the digital RF domain. The astronomer's have been doing it for over forty years that way. In fact the astronomer's are now doing it at optical wavelengths.
There is also a long history of spoofing air search radars by syncing to their antenna rotation rates and precisely clocking their PRF’s and then using that information at a different physical locations to receive and plot their reflected pulses. This was once used to determine the coverage areas of long range low frequency air search radar’s and to identify their blind spots caused by antenna radiation patterns and their transmitted wave front’s incident reflections and cancellations created by the surrounding train that they were located in. Patterns that were often unique to where the radars were physically located. Newer air search radars are far less prone to these deficiencies and often use far more complicated scan patterns that are less predictable. Few types of radars are more complicated or less predictable than AN/SPY-1D.
But if you were to operate several AN/SPY-1D's in a master slave configuration, so that the master preemptively sends to its slaves a few mill-seconds in advance the scan pattern, power levels, frequencies and beam formed elevation combinations, and times of its next series of transmissions, the slaves could effectively scan passively the same area of space while the master transmits. Thus passively tracking the same targets and then combining the results.
It comes to mind that this is a much discussed process of defeating aircraft stealth shaping technology. However, sorry to say his it is doubtful to work in this case as I have constructed it, (just three participating units). Where we are talking about the distance between the three ships being at a maximum separation of only 80 miles, it probably will not be enough separation. At this distance you are unlikely to get the minimum 30 degrees of separation of the reflected signals off the boar-sight of the active radar considered necessary to defeat aircraft stealth shaping technology by a collocated receiver. At least not before the aircraft gets so close to be of any practical use. But there are many other advantages to this technique.
One of the most obvious is in increased target classification and discrimination capacities that are not possible to obtain from just one viewing angle. Question; is the relatively strong radar return you are receiving from an air contact, that of one or is it two or even more aircraft or even missiles flying in close formation? Or is it just one larger target? This method can be used to discriminate the RF return as separate targets. This would includes the very difficult to discern, head to tail formations, which attack aircraft are sometime known used to confuse radar operator’s as to raid size for this very reason. Also, target classification, as in the form of (non-cooperative IFF) is also possible using Speckle intereromerty. Information on the physical features of the contact like its true physical size (not just relative signal return), its shape, is it (jet, rocket powered, or propeller driven), and the number of engines or bombs hanging from the wings might come in handy to the decision makers. Might be useful in a situation of say, telling the deference between a F-14 on an attack run and that of an AIRBUSS A-330 taking off from a dull use airport that also is also used by military aircraft? It certainly would help is identifying decoys from real warheads when used in the ABM mode.
It has not gone beyond my notice that there are many other advantages, found in many other military requirements both upon land and the sea, that a very high capacity real time, point to point, secure and undetectable data link can provide beside the capacity of combining raw sensor data into synthetic arrays, though this is an entirely new and powerful capacity. And that as more cooperating units are added in linear progression that the power of the system grows exponentially, as long as the bandwidth is not exceeded. Please feel free to add your own thoughts but what I am really interested in, if any of you out there in the wilds of the Internet, that may have knowledge and experiences I do not have, can see any large and difficult problems, or show stoppers, be they ether in a tactical or technical sense in my proposal or in the general ideas I have proposed? Thank you
The control of the electromagnetic spectrum, both for your use and to deny its use to the enemy is at the heart of all aspects Electronic Warfare. Any method, ether by the use of tactics or technology that reduces the quality, power, duration, or frequency of energy emissions employed by active sensors or coincidental energy releases of your systems ether for detection, identification, navigation, propulsion, or communication, reduces the amount and quality of an adversary’s available information which then cannot be used against you. This lack of information to a possible adversary complicates and lengthens their decision making loop and severely decreases his number of safe options. Likewise anything that increases your situational information by merging passively obtained emitted energies, (including sound), is a plus. There is now a technology available that can allow us to do decrees our energy emissions and increases our situational awareness at the same time.
As reported in July/August issue of Defense Technology International magazine, MIT Lincoln Laboratory has produced an IR laser data link with 100 gigabit capacity (I am assuming that they mean 100 gigabits per second capacity) for use in airborne systems. It is intended to download complete data files and raw sensor data in real-time to ground stations for analysis from airborne surveillance drones. The very large data files coming from various airborne sensors are today too large for easy on-board storage, or when they are stored for later delivery they often incur disadvantaged in their utility because of lack of timeliness, and if stored they must then be so compresses that they may lose valuable data. This lightweight device is said to work at ranges up to 40 miles. There are other better uses for this type of capacity as I will try to demonstrate. These new demonstrated abilities can change most of what we now think we know of how to conduct modern warfare.
Up to now military data links have been exclusively used for the transfer of processed data in symbolic form. That is, even when these systems are working at their best, all you get is somebody’s best guess of what is going on based upon their limited sensors that they are sufficiently interested in, on their end of the tactical picture, to inter into the system. If you are operating at the other end of this link you may be lucky to get anything tactically useful to you? Remember, that guys working on the other end whom must do all the work of entering and updating information into the system will only enter what he thinks is important based upon his priorities.
I will not get into all the issues that are evolved just in the mechanics of transferring processed data across various systems, platforms, frequencies, formats, and the time delay issues deriving from the communication links themselves, all of which were originally designed for other tasks and then were later adapted towards the current network centric pyridine on informational warfare. It would make your head swim.
Now it has become possible by using this new technology, (based upon high capacity IR laser data links) to implement a new form of information transfer within real time tactical situations, changing once again, the current network centric pyridine. The easiest and quickest place to implement this new capacity is between already existing compatible systems. The first obvious application well be in the combined operations of naval task-forces.
By utilizing already existing platforms containing identical equipment, a new enhanced functionality of a kind never before seen in warfare is now possible. The availability of a extremely high bandwidth real time data streams, implemented in the form of a tight two way secure beams of very difficult to detect out of boar-sight light, used within the line of sight can besides transferring huge amounts of data of types which are already being transferred by less secure and slower means, it can also be used in completely new ways to get never before seen capacities.
As a natural by product of laser data link’s intrinsic operation, the equipment will simultaneously and continually plot the exact relative ranges and bearings between all the linked units to within a fraction of a meter and can set a time synchronization standard between all the various systems to a level of less then a few micro-seconds, even without the assistance of an external time standard like GPS, and perhaps even far better. These features will become crucial to the discussion later when we talk about the issues that impact upon time and wavelength.
These capacities make it possible to now combine more than just symbolic knowledge (icons on a computer screen and some associated script but raw uncompressed sensor data). Sensor data from identical systems operating from dispersed physical locations that can be formed into synthetic virtual sensor array of great size and power. These synthetic virtual arrays can create a far more powerful and complete picture of the situational awareness in a large geographic area than has ever been before possible while at the same time reducing the number of tattle-tail energy emissions that reveal the locations and composition of the task-force.
I will use as my example a simple case of just three Arieighs Burke flight II destroyers sailing together in a typical task-force screening formation and just a few of the possible synergies that can be obtained when their combat sensor system’s raw sensor data are virtually merged. We will use in this example the AN/SPY-1D Radar of the Aegis weapon system, AN/SLQ-32 (v3) the ESM section of that countermeasures suite, and parts of the AN/SQQ-89 sonar suite (composed of the AN/SQQ-53C Hull Mounted Sonar, AN/SQR-19 Towed Array Sonar, AN/SQQ-28 LAMPS MK II Sonobuoy Processing System, and the ASWCS MK116 MOD 7 Anti-Submarine Warfare Control System.
We will first take the easiest application for novices unfamiliar with the concepts of data merging to understand. That of real time raw data sharing of ESM (electronic support measures) intercepts. Something that has been done for many years by dedicated ground stations to good effect. ESM intercepts, ether threats correctly identified and properly filtered or not, often get shorted out of the command loop decision making process because unless the intercepted signal indicates that it, a jet or missile, is coming strait down your throat to possibly kill you, they do not give the shouter much usable information or a usable target. A bearing line is not a plot and gives decision makers too little useful information and thus he or she will prefer other means of verifying the possible threat. If a signal's origin is beyond the horizon and not discernible by other means, the commander if he or she is sufficiently concerned by the ESM report will launch something like a helicopter to validate it and in so doing, will give away their own position and capacities.
There are four ways of locating an emitter passively,( amplitude, phase, time of arrival, and Doppler) two are practical to use with the equipment under discussion, one of these is triangulation DF based upon signal strength (amplitude) and the other is by measuring the time of arrival using three or more dispersed receivers taking some definable RF signal feature, like Chirp as a time point.
At present triangulation DF is possible only within some critical operational frequencies, though it is, I am sorry to say, seldom used to its full potential. It is done by using processed data through the NTDS (Naval Tactical Data System) system. But the precise DF capacity of the ship’s equipment, both to the degree of the equipments DF accuracy, speed of acquisition, and in the frequencies available are quite limited. This is mainly due to the required antennas size needed for DF analyses using the signal strength method for many of the most useful lower frequencies. Topmast space for antennas of any kind is always at a high premium on warships.
I do not know of any combat ship that has DF capacity RF in the HF, VHF or UHF bands. The VHF and UHF bands are used extensively by both small and medium size surface craft of both civilian and military use, and they are used universally by aircraft. I have on occasion even seen submarines do a quick pop up for just long enough to give a (shout out) from time to time. They do so like bragging about their success in getting away from the surface guys. They can do this with impunity because they know that tactical units, (not shore based intercept stations), do not have DF capacity in these RF ranges. Usually submariners are the supreme masters in the use of all aspects of Cover and Deception but they can be arrogant at times.
The signals of these frequencies travel far beyond the radar horizon. The time of arrival method of locating both commutations and navigation emissions can be done quite easily if you have the time domain and the space domain between the receiving units very well defined (a few inches and micro-seconds). This triangulation technique can not only be used to plot instantaneous positions by use of RF ground waves but just as the use of continues plots have been used in conventional radar, consecutive plots of this kind can give you the approximate course and speed as well as location of these emitters. Think about what that means to the task-force commander when the task force is operating in emission silence mode (Com-Con) and how much more attractive to the commander it would be to operate in that mode if this kind of information is available for free?
Now let us consider the sonar suite. First the AN/SQR-19 Towed Array Sonar is already, (as it is physically constructed and used), a true synthetic array, where the signal processing techniques of beamforming and intereromerty are used to combine the outputs from the many and various passive hydrophones along the string into one result. The more electronically combined signals added from additional sensors, increase the over all sensitivity of the systems (its detection and identification ability). Added together above that of the individual ship’s abilities and provides better source directionally. By combing the signal outputs of the three separated AN/SQR-19’s together not only do you get a far better directionally coming from their different locations, perhaps rising to the level of getting instantaneous three-dimensional plots, but it will have (as a system), better total overall system sensitivity in finding and identifying targets initially. To do all these wonderful things, all that is required is to connect the systems through the real time data link of sufficient bandwidth, add additional computing power (cheaper every day they like to say in silicon valley), and create some additional computer code. A real no brainier if you ask me.
You can do the similar thing with the AN/SQQ-53C Hull Mounted Sonar system but in this case the real advantage is that just one ship within the task-force can go sonar active (perhaps operating at its full power) while the other ship’s in the task-force systems remain passive. In so doing the passive ships will not have to give away their positions or if they have already been detected and tracked by a submarine, they may not have necessarily been identified as to their hull type and just what function within the taskforce they are serving. From the Submarine’s point of view, the question they must always ask themselves; who out there could be the shooter? In fact, if the submarine happens to be physically closer to one of the passive units, than it is to the active sonar radiating ship, the passive ship may get a stronger return (depending of relative aspect ratio to the source and sound propagation conditions) from the sub than that which the active ship receives and hence it gets a better targeting solution without completely giving itself away.
Now for the hardest test of this concept, the AN/SPY-1D Radar of the Aegis weapon system. The difficulty of combining the information from different propagating wave fronts, collaterally received at different locations, is proportionally more difficult with the increase in frequency utilized by the sensor system and with the corresponding decrease in the wavelength of those systems, (time and distance measurement). Sound waves are much easier to combine than microwaves. So easy that it can be easily done within the analog domain but it can and has successfully been done in the digital RF domain. The astronomer's have been doing it for over forty years that way. In fact the astronomer's are now doing it at optical wavelengths.
There is also a long history of spoofing air search radars by syncing to their antenna rotation rates and precisely clocking their PRF’s and then using that information at a different physical locations to receive and plot their reflected pulses. This was once used to determine the coverage areas of long range low frequency air search radar’s and to identify their blind spots caused by antenna radiation patterns and their transmitted wave front’s incident reflections and cancellations created by the surrounding train that they were located in. Patterns that were often unique to where the radars were physically located. Newer air search radars are far less prone to these deficiencies and often use far more complicated scan patterns that are less predictable. Few types of radars are more complicated or less predictable than AN/SPY-1D.
But if you were to operate several AN/SPY-1D's in a master slave configuration, so that the master preemptively sends to its slaves a few mill-seconds in advance the scan pattern, power levels, frequencies and beam formed elevation combinations, and times of its next series of transmissions, the slaves could effectively scan passively the same area of space while the master transmits. Thus passively tracking the same targets and then combining the results.
It comes to mind that this is a much discussed process of defeating aircraft stealth shaping technology. However, sorry to say his it is doubtful to work in this case as I have constructed it, (just three participating units). Where we are talking about the distance between the three ships being at a maximum separation of only 80 miles, it probably will not be enough separation. At this distance you are unlikely to get the minimum 30 degrees of separation of the reflected signals off the boar-sight of the active radar considered necessary to defeat aircraft stealth shaping technology by a collocated receiver. At least not before the aircraft gets so close to be of any practical use. But there are many other advantages to this technique.
One of the most obvious is in increased target classification and discrimination capacities that are not possible to obtain from just one viewing angle. Question; is the relatively strong radar return you are receiving from an air contact, that of one or is it two or even more aircraft or even missiles flying in close formation? Or is it just one larger target? This method can be used to discriminate the RF return as separate targets. This would includes the very difficult to discern, head to tail formations, which attack aircraft are sometime known used to confuse radar operator’s as to raid size for this very reason. Also, target classification, as in the form of (non-cooperative IFF) is also possible using Speckle intereromerty. Information on the physical features of the contact like its true physical size (not just relative signal return), its shape, is it (jet, rocket powered, or propeller driven), and the number of engines or bombs hanging from the wings might come in handy to the decision makers. Might be useful in a situation of say, telling the deference between a F-14 on an attack run and that of an AIRBUSS A-330 taking off from a dull use airport that also is also used by military aircraft? It certainly would help is identifying decoys from real warheads when used in the ABM mode.
It has not gone beyond my notice that there are many other advantages, found in many other military requirements both upon land and the sea, that a very high capacity real time, point to point, secure and undetectable data link can provide beside the capacity of combining raw sensor data into synthetic arrays, though this is an entirely new and powerful capacity. And that as more cooperating units are added in linear progression that the power of the system grows exponentially, as long as the bandwidth is not exceeded. Please feel free to add your own thoughts but what I am really interested in, if any of you out there in the wilds of the Internet, that may have knowledge and experiences I do not have, can see any large and difficult problems, or show stoppers, be they ether in a tactical or technical sense in my proposal or in the general ideas I have proposed? Thank you
Sometimes less is more and I should take my own advice.