System defences and passive ship detection, targeting.

sideranautae

Mongoose
An overlooked (in Trav game material) technology for system defense systems is what is known as Passive Radar. In TL 10+ systems interested in system defense there would be scrambled radar broadcast stations (probably placed in small buffered asteroids) throughout the entire star system constantly beaming. System defense forces would use this (via their own radar receivers) to detect intruders passively via radar. This is a way to use Active sensors without giving out your ships locations. It enables weapon lock with no active EMS...

Just wanted to put this out as a tech feature...
 
Not a bad idea :D I like it.
Of course it would be a bit more complex, and require some serious effort to work out the bugs in the system for the system installing it...but that's going to happen with any detection system.

basically it sounds a lot like an advanced version of Semi-active system used by older air to air missiles, like the Sparrow. It would work, it wouldn't be as precise as a conventional sesnors, but it would act like a wide area motion tracker.
By comparing snapshots of the reflected energy, a system could spot moving objects by detecting changes in the reflected energy....Basically a computer would look at snap shot A, and snapshot B and run an algorithm to spot differences in the two.
Adding filters to kick out known objects, and scanning for friendly transponders, and roughly estimate the size and velocity of objects in the area would allow the system to send less garbage data to the human operators.
While it wouldn't be very useful for accurate tracking and ranging, it would give human operators a rough idea of size, shape, velocity, and course. More advanced systems and patrol craft could then sweep with their own sensors to get a better idea of what they were dealing with
In combat it would also make a nasty intruder glow like a light bulb to any friendly sensor system, especially the smaller, cheaper, sensors of a missile/torpedo. it would allow small fast less easily detected( read less likely to be recognized as a manufactured object) vessels fire off missiles before the enemy realized the rock they were cruising near is actually a disguised combat vessel or platform.

of course I wouldn't want to be the poor soul tasked with looking at all the returns spit out by the system. Especially in a system with a lot of rouge bodies zipping in and out.......Hmmmmm well there's another use for it. Detecting rouge bodies as they enter the system.
 
wbnc said:
Not a bad idea :D I like it.
Of course it would be a bit more complex, and require some serious effort to work out the bugs in the system for the system installing it...but that's going to happen with any detection system.

basically it sounds a lot like an advanced version of Semi-active system used by older air to air missiles, like the Sparrow. It would work, it wouldn't be as precise as a conventional sesnors, ...


This system has been (and is used) to a high degree by the USA. It is computerized. Humans don't parse the data. This is TL 7 real time combat system. It is HIGHLY accurate as a weapon targeting system.

At higher TL's it would be even easier.
 
I would expect any system with the money to have a network of traffic satellites spread out that can also double as early warning stations.

But it comes down to (a) credits, and (b) how my polities are within the system. Remember that a planet doesn't own any more real estate than up to ti's 100D limit. There may be colonies, stations or other settled planets within the system, but they could each have their own government and may, or may not, work in conjunction with the planet that has the primary spaceport for the system.

It's not a bad idea, but cash-strapped systems are probably going to be more interested in being able to pay for local defenses and hulls. It's up to the Imperium to pay for that kind of thing if they are on a border. Systems that don't face an external enemy probably would never invest in such a thing since they had no need.
 
phavoc said:
But it comes down to (a) credits, and (b) how my polities are within the system. Remember that a planet doesn't own any more real estate than up to ti's 100D limit. There may be colonies, stations or other settled planets within the system, but they could each have their own government and may, or may not, work in conjunction with the planet that has the primary spaceport for the system.

Correct. However: A) for any decent sized main world the cost is a pittance. B) There is NO prohibition by the 3I against a world setting up passive detection nets in a system. C) no sane gov (as defined by the 3I) is going to oppose system defense.

phavoc said:
It's not a bad idea, but cash-strapped systems are probably going to be more interested in being able to pay for local defenses and hulls. It's up to the Imperium to pay for that kind of thing if they are on a border. Systems that don't face an external enemy probably would never invest in such a thing since they had no need.

It isn't a either/or situation. It's hard to put it briefly but, just suffice it to say that NOT having/using a system like this INCREASES the cost of those local defense hulls.
 
I don't disagree, if you know where the enemy is, you can use the few hulls you have the best way possible. You still would need to pay for, and service, the satellites. Not an insignificant undertaking, though possibly within the reasonable range of a planet with a decent economy.

The question becomes - who are they defending the system against? If there aren't external threats then your opposition is (a) other imperial worlds from outside your system, (b) other imperial worlds inside your system, or (c) pirates, revolutionaries and malcontents. I'm aware all three scenario's potentially exist, but we really know nothing of intercine warfare between planets and systems to be able to judge if this is a reasonable issue or not.

But I do like the idea of traffic satellites. I call mine "cueballs", though they are meant to be placed above smaller starports with lower tech, not monitoring the system for invaders.
 
phavoc said:
I don't disagree, if you know where the enemy is, you can use the few hulls you have the best way possible. You still would need to pay for, and service, the satellites. Not an insignificant undertaking, though possibly within the reasonable range of a planet with a decent economy.

Given that our crappy TL 7 satellites go for many years with no servicing, I think TL 10+ ones would last for decades.

phavoc said:
The question becomes - who are they defending the system against? If there aren't external threats then your opposition

I already answered that question by qualifying who would use the system in my original post... :shock:
 
Okay did a basic sensor-sat for fun and giggle..and maybe use later.
Hull type s1..........................10tons........Mcr 1
Powerplant: sA...........rating 2.....0.5 tons.....Mcr 1
Solar Panels...............rating 1... 0.5 tons.... Mcr 0.05
Fuel 1 month ............................ 2tons
Computer : type I
Electronics: Basic Military Extended arrays 6 tons Mcr3

Drone control: 1.5 tons, Mcr5
Automated, Remote, Non-Combat capable TL12
Characteristics 7
Intellect/3
Recon/2
Comms/2
Sensors/3

ugh I really need to figure out how to do tables here....

Mcr 9.045 for a standardized design, possible lower if ordered in bulk.

It has fuel for up to a month if using active sensors, and can be operated in passive mode for an indefinite time. extended arrays greatly increase the range it can detect a target at.If the target as illuminated by one of those transmitter arrays it might greatly increase it's passive sensor ranges as well.

at 9 Mcr a piece and wired into a detection grid, any reasonably large world could afford quite a few of these little guys. It would save on patrol ships, and personnel to man them. If the satellites had the target illuminated for them they could handle a fairly broad area around a planet, or vital facility.

you could track normal traffic, smugglers, pirates, people trying to skip out on their berthing fees etc...even if there are no military threats/heavy starship traffic, a hand full of these could be positioned and dedicated to spotting the odd asteroid, or meteor heading for the planet.
 
wbnc said:
Okay did a basic sensor-sat for fun and giggle..and maybe use later.
Hull type s1..........................10tons........Mcr 1
Powerplant: sA...........rating 2.....0.5 tons.....Mcr 1
Solar Panels...............rating 1... 0.5 tons.... Mcr 0.05
Fuel 1 month ............................ 2tons
Computer : type I



And to think. That is designed with the clunky, TL 3 ship design rules. In reality they would powered by a nuke battery (alpha/beta/gamma voltaics) that has a half-life of years. In a much smaller package and price.

Nice work up.
 
The solution to such nets will be advances in stealth and jamming technology as the US does today. This means the stealth jump and the stealth coating option will become standard including more advanced forms and the EMS suppression tech from other Traveller editions will return. TL 15 Black globes will rear their ugly heads even more. If a star system can field very expensive EWSs, a determined opponent will pay to neutralize such an advantage. Tit for tat for tit forever.
 
sideranautae said:
And to think. That is designed with the clunky, TL 3 ship design rules. In reality they would powered by a nuke battery (alpha/beta/gamma voltaics) that has a half-life of years. In a much smaller package and price.

Nice work up.

Thanks. I may see what other alternates could be used to make them cheaper. After all the object would be as low a cost per unit as possible.



And as for stealth,satellites, you don't have to be invisible to sensors, you just have to NOT look like a threat to the guy operating the sensors. and if they are using passive sensors only as they try to slip through a detection network, or more worried about armed starships lurking in the shadows of planets, and hiding in drifting natural clutter.... a satellite listening post might be just unobtrusive enough to be missed.

to escape detection/identification radar absorbent coatings, a surface that gives you the albedo of a harmless rock..or iceball.... Since the satellites, and receiver stations don't need to be mobile, you can park them and let them cool to very low temperatures. Especially if they are running on solar panels, or batteries.

So invisible to sensors stealth, not likely. "Is that a rock, or a listening post?" stealthy..more likely.
 
There is stealth in space as there is on Earth with shapes, radar absorbent coatings and EMS redirection or are we saying those stealth plane really don't exit? Traveller is also about advancing technology making such things more probable. Traveller is also about what if and maybe, not boring 'it can't happen so starships and space combat is impossible, let's not bother with scifi games' also known as the 19th century.
 
That setup sounds good for a important interdicted system. But what about a major commercial system with hundreds or even thousand of ships in the system at any given time.
 
rule of thumb the more moving parts in a system, the more chances you have of something breaking...and space ships, satellites, and orbital/deep space platforms count as moving parts.

A modern Aegis system can track multiple targets at once and coordinate a network of radar, and air defense systems. I don't imagine the systems hardware, or software would be taxed.
For example a normal air traffic control center, in a large city may be tracking hundreds of aircraft at the same time. it's hardware ca accurately track everything in the sky, and the computers will usually relay accurate information to the air controllers.

The problem with a system in a busy system would being the human element. Controllers, and defense/security coordinators might miss something. such as a smuggler, pirate, hostile masquerading as a friendly/legitimate ship...or worse a rushed decision may flag a perfectly innocent far trader as a suspicious or hostile vessel...if the crew is lucky they will just be boarded and searched...if it's an active engagement area the misidentified ship could end up the victim of an attack by system defenses.
 
In fairness, that's no different to any busy system. If you're jumping into a busy system which is considered sufficiently risky (due to nearby raider action, etc) for the defence fleet to be at 'weapons hot' then sooner or later you're going to have an incident, even if it's someone mis-jumping and landing in a military-restricted volume.

But yes, regardless of the technology actually used to do it (radar, IR, magic whommyness detectors), you'll inevitably find that one advantage an SDB has over an attacker is that a mainworld can set up big sensor arrays* in secure-ish close planetary orbit and pass a shared picture via data-link to the defending warships, whilst the attackers have to rely on sensor arrays which they can bring with them via jump**.



The problem with creating what's essentially a system-wide network of 'floodlights' (as far as the appropriate bit of the electromagnetic spectrum is concerned) is that your own ships are lit up too; if you're in range to see the bouy's radar pulse 'echo' off an enemy ship, they're in range to see the buoy's omnidirectional 'ping' echo off you (give or take minor changes in reflective signature). Hence no-one needs to use active sensors, and no-one really gets an advantage. Obviously you can try and gain an edge by using an obscure frequency band the enemy might not be listening on, but by TL10+ that's the sort of thing which a decent sensor suite can adapt to as quickly as you can change it.




* or interferometry-based nets of little sensor arrays networked together, which amounts to the same thing

** although expect to see deployable sensor array remotes to achieve the same effect.
 
locarno24 said:
The problem with creating what's essentially a system-wide network of 'floodlights' (as far as the appropriate bit of the electromagnetic spectrum is concerned) is that your own ships are lit up too; if you're in range to see the bouy's radar pulse 'echo' off an enemy ship, they're in range to see the buoy's omnidirectional 'ping' echo off you (give or take minor changes in reflective signature). Hence no-one needs to use active sensors, and no-one really gets an advantage. Obviously you can try and gain an edge by using an obscure frequency band the enemy might not be listening on, but by TL10+ that's the sort of thing which a decent sensor suite can adapt to as quickly as you can change it.

Correct. You only want to use to detection preparatory to you moving ships to intercept.

Interestedly I was just reading a Masters thesis from a grad of the Naval Postgraduate School. It dealt with creating a passive ranging and targeting system using IR. Creating that "Holy Grail of the defense community."

Based on what I read, that type of system would be practical within a couple of TL's EASILY...
 
If these things are using active radar, it would be easy for an agressor to randomly or suddenly take them out prior to an attack. Launch a few dozen missiles on ballistic trajectories shut down and when they get close enough their seekers home in (maybe like HARM would) on the emitter and all of a sudden your network goes dark.

Sure, you could replace them, but it would take time. Remote sensors are always at risk like that. I would assume you'd keep a set at about 100D, and then spread some more through the system. At least your closer ones would have a better chance of defending. Though to be sneaky you could have them randomly turn off/on, and move using their thrusters so that you could make it harder for the ballistic trajectory attacks.
 
phavoc said:
If these things are using active radar, it would be easy for an agressor to randomly or suddenly take them out prior to an attack.

The attacker would be spotted LONG before they could destroy them. Also, you don't have them all on at same time... You have back ups. :wink:

Once you start blasting and maneuvering all over you have lost ANY chance of remaining unknown and hidden. Also, see weapon range tables. You aren't going to be blasting ANY of these when you jump in system. You will have to travel quite a bit to get close enough.
 
These uber defense systems will guarantee total bankruptcy of any system. Death by financial paranoia followed by the space Huns.
 
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