Sensors
This article contains information relevant to both the C# and VB6 versions of Aurora. Where differences exist, they are noted in the appropriate sections.
Sensors are components that detect the presence of target objects either by detecting energy emitted by the target or by reflecting energy off them and detecting the reflection. Active Sensors are essential for target acquisition, and may out-range passive sensors for finding large objects with small signatures, but may give away your position. Passive EM Sensors and Thermal Sensors don't give you as much information as actives, but they could allow you to stay undetected.
Sensor data is shared, hence the sensor range of a fleet depends only on the sensor range of the ship with the longest range. While having some medium-sized sensors on each warship can be useful as a backup, it is more useful to build dedicated surveillance vessels with long-range sensors.
- Sensor efficiency can be improved with research, while ECM jamming and stealth technology can reduce passive and active sensor detection range.
- Jump shock will render sensors temporarily blind. You can view the active and passive sensors detection radius of your ships and installations in the System Map window by checking the "Passive vs Signature ##" options on the Display tab (C#), or adjusting the Sensors tab slider values (VB6). If you think a 100-strength contact might be out there somewhere, select a signature strength of 100 and you'll see at what distance your sensors would pick it up.
- In VB6, every military and commercial ship has intrinsic thermal and EM sensors of strength 1 (not listed as components). In C#, these do not exist, but small sensors are commercial components, and much more effective than in VB6, so a useful sensor suite can be added at a lower cost.
Active Sensors
An active sensor is a "radar" component that gathers target data by bouncing gravitational pulses off a target. This is necessary to open fire on a target. Active sensors allow a ship or a missile to detect targets equal to or above its stated resolution (i.e. ship size) within its stated range: the higher the resolution value, the greater the range, but ships smaller than the resolution are more difficult to detect. Active sensor emissions can be detected by passive EM sensors, which can prove a serious tactical vulnerability.
The idea is that as with real-life radar emissions, the signal from your sensor has to travel the distance to a target twice: once to the target, where part of the energy is reflected, and once back to your ship, where an EM sensor picks up the tiny "echo". Therefore your outgoing signal can possibly be detected by other ships with EM sensors much further than your sensor can see those ships.
Actives are designed based on the role intended for that sensor. An area search sensor might be designed with a large resolution to find large enemy ships, while a sensor designed to detect fast attack craft would need a small resolution. Missile detection sensors usually have a resolution of 1, which is the lowest possible. A versatile fleet will employ a multiple sizes/resolution sensors. Design considerations are discussed in-depth here: Active Sensor Design.
Active Sensor target detection capabilities can be increased through background research, while Cloaking and Jammer/ECM technology employed by the enemy will making it harder for active sensors to detect. Active sensors also gather tactical intelligence, i.e. they can tell you the target's size.
Passive Sensors
Passive sensors emit no energy, instead gather target data by detecting incoming emissions. Thermal Sensors pick up the infrared emissions from ship and missile engines, while EM Sensors pick up the emissions from active sensors and shields. Both will detect Colonies, where higher EM to thermal ratio seem to indicate the presence of larger civilian populations and advanced installations.
The stronger the emissions, the farther it can be detected. The formula varies by version:
C#: Range = sqrt(Sensitivity * Signature strength) * 250,000 km VB6: Range = Sensitivity * Signature strength * 1,000 km
Where:
Sensitivity = Sensor size * Sensitivity tech level used
Bigger is always better (if you can afford the ship carrying a huge sensor, at least...), but the gains from size are moderate in C# and very large in VB6.
Thermal Sensors
A Thermal sensor is a passive sensor sensitive to infrared emissions, and can detect Ship/missile engines or colony activity thermal signatures. They're not so good at finding anything powered down or moving under minimal power, though. Engines designed with thermal reduction technology or travelling at less than full speed will emit less heat, and will be harder for Thermal sensors to detect. You can set the speed in the Task Group window.
EM Sensors
An EM Sensor is a passive sensor that detects electromagnetic emissions from active sensors, shields and colonies on a planet. Good for locating civilian populations or fully powered military fleets. Not so good at finding a ship under emissions control, which has actives and shields switched off and does not emit any EM at all. However, an enemy ship with no active sensors could be a sitting duck for your missiles, if you do manage to find it...
Note
- There also Geological Survey and Gravitational Survey sensors.
- Sensor calculation can be taxing on your system, see Game Slowdown for info on related settings.