OneShot
05-30-2005, 07:58 PM
Taken from : SubSim DW Tactics & Tips (http://www.subsim.com/ssr/tip_dangerwaters.html)
The bow sonar only picks up higher frequency ranges, so detecting subs and warships with this will be difficult. Even though this was mentioned in the old 688i game, it would appear they 'relaxed' the parameters to where it would pick up anything. Based on that I thought something was wrong in the new game. I went back and created a mission with a speedboat instead of a warship and presto, the bow array did indeed pick it up. User error, as usual. It is much harder to detect contacts, but is probably more realistic and more challenging which is fine.
There are no numbers on the Akula bearing Indicators for the inner arrays. You must refer to the numbers on the outer edge of the display.
Be aware that when you turn Ownship your towed array does not begin to turn until it reaches the point in the ocean where the ship began its turn. As a result, Ownship appears as a contact on the towed array during turns.
Ownship’s speed can affect your ability to detect contacts in Narrowband. When the entire signal line is near the top of the display this indicates that background noise is very high. This usually happens when your speed is over 5 kts for hull array contacts or over 15 kts for towed array contacts. Decrease your speed to reduce water flow over the array.
Straight lines indicate a consistent signal. Curved or wavy vertical lines represent distortions or variations in the signal.
If the signal is weak you may have to click more than once to designate the contact and assign the tracker.
You cannot assign a tracker while the game is paused.
If the contact that you have classified in Narrowband has not yet been assigned a Contact ID (S1, S2 etc), a contact ID symbol does not exist for that contact on the Nav map. You can not complete the contact classification process on the Nav map until the contact has been assigned a Contact ID.
You can classify contacts in ESM, Stadimeter and Narrowband. The Classification dialog highlights the name of the class that was most recently classified by one of these sensors whenever you select that contact on the Nav map.
Turns per knot for military and civilian ships are found in USNI Reference. Click CIVILIAN in the Country column then the name of the ship type to find TPK information on Civilian ships.
To stop the transmission of continuous active sonar pings on any of the submarines, click again on the TRANSMIT button
Due to varying water temperatures at locations around the world, a distinct thermal layer is not always present.
People complaining about the auto-crew picking up contacts that you can't see in the waterfall. Well they may not show up graphically, but if you scan the bearings, you will get a small signal-to-noise hit of 4 to 8 or so. This is a potential contact even though it doesn't come through on the speakers, doesn't show a line in ITA, and can't be classified in narrowband. S/N is shown in the Seawolf on the right numerical data display, can't remember off hand if/where it is on the Akula or 688i. by Paul Tobia
"I was playing "Iran the Straits" last night and things were going fine when all of a sudden my towed array started showing bright background noise as if I were moving at high speed, which I wasn't. The bow sonar didn't display this noise. In the narrowband sensors, it kept pulsing between high-noise and low-noise readings but eventually settled on high-noise." The game models physics very carefully. In shallow water at low speeds your towed array can actually drag the bottom and cause the phenomenon above. Retract it some, gain speed, or change your depth.
Sonar: Broadband
Broadband is the default sonar function. It is used to detect and track broadband frequency noise emanated from surface ships and submarines. Biologics such as whales and shrimp can also be detected in broadband.
Sonar: Narrowband
The Narrowband function is used to detect and track narrowband frequency noise emanated from surface ships and submarines. The Narrowband Station is also used to classify contacts. The sound signature of a selected contact is compared to a library of known sound signatures. Only sources with similar signatures are presented to help determine the most likely sound source.
Sonar: DEMON
DEMON is an acronym for Demodulated Noise (DEMON). The DEMON Station is used to determine the contact’s speed. Here you can also determine the number of blades on the contact’s propeller, which can help you classify the contact.
Sonar: Active
In Active Sonar, a ping or a series of pings is transmitted. The resulting echoes from an object are used to determine that object’s bearing and range.
Sonar: Active Intercept
The Active Intercept Display provides information on an entity that is transmitting active sonar pings. It gives information on the transmitting entity’s bearing, the interval between pings, the age of the last signal, and the signal strength. Knowing the signal strength might also assist you in determining the relative proximity of the active sonar source.
Sonar: SSP
The Sound Speed Profile (SSP) displays the speed at which sound is transmitted at various depths in the ocean at your current location. Water tends to form distinct layers of density. These layers affect sonar transmissions. Knowing the location of the layer in your area is important since the layer can affect your ability to detect enemy ships and subs and also helps you hide from them.
Sonalysts Game Design Notes:
The passive sonar modeling in Dangerous Waters was modified from 688I in an
effort to upgrade the sonar detection and classification performance. Sub
Command models the individual variables in the passive sonar equation:
Passive Sonar Signal Excess = Radiated Noise - Propagation Loss - Interfering Noise - Recognition Differential
1. Radiated Noise is the initial source level of the signal that emanates
from the contact. Broadband radiated noise varies with speed, narrowband
radiated noise does not.
2. Propagation Loss is the amount of loss the source signal sustains as it
travels from the contact to the sonar. Dangerous Waters calculates proploss on
the fly, accounting for the loss due to interaction of the signal with the
acoustic boundaries (surface, bottom, and thermal layer) and the
attenuation loss of the signal as a function of range.
3. Interfering Noise is a combination of background noise (sea state, rain,
shipping density) and self noise (noise emanating from the detecting ship)
that is a function of own ship speed..
4. Recognition Differential is how well a sonar system can differentiate a
signal from the background noise. Dangerous Waters models separate sonar
Recognition Differentials depending on sonar type and model.
All these variables are modeled in Dangerous Waters to determine whether or not
to display a signal on a sonar screen, and how brightly to display the signal.
Broadband radiated noise varies by platform class, and is adjusted for
target speed. Broadband radiated noise values are modeled for
representative frequencies in the 2 kHZ - 4kHZ range.
Narrowband radiated noise is modeled by assigning a narrowband profile to each
appropriate platform - 5 discrete narrowband frequencies. The 5 discrete narrowband
lines range in frequency from 50 Hz - to - 2 kHZ. All U.S. built ships
will have a 60 HZ lines because the U.S. uses 60 cycle electrical
equipment. The rest of the world uses 50 cycle electrical equipment, so
their narrowband profile will have a 50 HZ line.
Low frequency signals propagate through water with much less loss than do
high frequency signals. Therefore, in most cases the best/initial
detection sensor will be the detection of narrowband lines on the towed
array. The window at the top of the Narrowband Station allows the user to
perform a narrowband search. Even though a signal is not visually apparent
in the search window, moving the cursor through all the bearings may
discover a narrowband contact line that will then be displayed in the
middle window. This occurs because the sonar system is able to pull a
signal out of the noise. This is the systems Recognition
Differential. This is the reason why an auto Sonarman will report a
contact that the player does not visually see on the Broadband screen.
The lower frequency lines will be detected first as the range between ships
closes, and the brightness of the lines will depend on the calculated
Signal Excess. The Broadband Station will generally detect after detection
has been made on the Narrowband Station. Towed arrayed broadband will
detect first over the spherical and cylindrical arrays because of it's
lower frequency band and better recognition differential. However,
spherical and cylindrical array detections eliminate the problem with the
ambiguous towed array detection.
The environmental inputs for each mission have a major effect on the sonar
detection performance. The inputs are environmental profile type (surface
duct, convergence zone, bottom limited), bottom type (rock, mud, sand), and
sea state (0-5). The depth of the water is also a major factor. These
inputs are available in the mission editor.
The bow sonar only picks up higher frequency ranges, so detecting subs and warships with this will be difficult. Even though this was mentioned in the old 688i game, it would appear they 'relaxed' the parameters to where it would pick up anything. Based on that I thought something was wrong in the new game. I went back and created a mission with a speedboat instead of a warship and presto, the bow array did indeed pick it up. User error, as usual. It is much harder to detect contacts, but is probably more realistic and more challenging which is fine.
There are no numbers on the Akula bearing Indicators for the inner arrays. You must refer to the numbers on the outer edge of the display.
Be aware that when you turn Ownship your towed array does not begin to turn until it reaches the point in the ocean where the ship began its turn. As a result, Ownship appears as a contact on the towed array during turns.
Ownship’s speed can affect your ability to detect contacts in Narrowband. When the entire signal line is near the top of the display this indicates that background noise is very high. This usually happens when your speed is over 5 kts for hull array contacts or over 15 kts for towed array contacts. Decrease your speed to reduce water flow over the array.
Straight lines indicate a consistent signal. Curved or wavy vertical lines represent distortions or variations in the signal.
If the signal is weak you may have to click more than once to designate the contact and assign the tracker.
You cannot assign a tracker while the game is paused.
If the contact that you have classified in Narrowband has not yet been assigned a Contact ID (S1, S2 etc), a contact ID symbol does not exist for that contact on the Nav map. You can not complete the contact classification process on the Nav map until the contact has been assigned a Contact ID.
You can classify contacts in ESM, Stadimeter and Narrowband. The Classification dialog highlights the name of the class that was most recently classified by one of these sensors whenever you select that contact on the Nav map.
Turns per knot for military and civilian ships are found in USNI Reference. Click CIVILIAN in the Country column then the name of the ship type to find TPK information on Civilian ships.
To stop the transmission of continuous active sonar pings on any of the submarines, click again on the TRANSMIT button
Due to varying water temperatures at locations around the world, a distinct thermal layer is not always present.
People complaining about the auto-crew picking up contacts that you can't see in the waterfall. Well they may not show up graphically, but if you scan the bearings, you will get a small signal-to-noise hit of 4 to 8 or so. This is a potential contact even though it doesn't come through on the speakers, doesn't show a line in ITA, and can't be classified in narrowband. S/N is shown in the Seawolf on the right numerical data display, can't remember off hand if/where it is on the Akula or 688i. by Paul Tobia
"I was playing "Iran the Straits" last night and things were going fine when all of a sudden my towed array started showing bright background noise as if I were moving at high speed, which I wasn't. The bow sonar didn't display this noise. In the narrowband sensors, it kept pulsing between high-noise and low-noise readings but eventually settled on high-noise." The game models physics very carefully. In shallow water at low speeds your towed array can actually drag the bottom and cause the phenomenon above. Retract it some, gain speed, or change your depth.
Sonar: Broadband
Broadband is the default sonar function. It is used to detect and track broadband frequency noise emanated from surface ships and submarines. Biologics such as whales and shrimp can also be detected in broadband.
Sonar: Narrowband
The Narrowband function is used to detect and track narrowband frequency noise emanated from surface ships and submarines. The Narrowband Station is also used to classify contacts. The sound signature of a selected contact is compared to a library of known sound signatures. Only sources with similar signatures are presented to help determine the most likely sound source.
Sonar: DEMON
DEMON is an acronym for Demodulated Noise (DEMON). The DEMON Station is used to determine the contact’s speed. Here you can also determine the number of blades on the contact’s propeller, which can help you classify the contact.
Sonar: Active
In Active Sonar, a ping or a series of pings is transmitted. The resulting echoes from an object are used to determine that object’s bearing and range.
Sonar: Active Intercept
The Active Intercept Display provides information on an entity that is transmitting active sonar pings. It gives information on the transmitting entity’s bearing, the interval between pings, the age of the last signal, and the signal strength. Knowing the signal strength might also assist you in determining the relative proximity of the active sonar source.
Sonar: SSP
The Sound Speed Profile (SSP) displays the speed at which sound is transmitted at various depths in the ocean at your current location. Water tends to form distinct layers of density. These layers affect sonar transmissions. Knowing the location of the layer in your area is important since the layer can affect your ability to detect enemy ships and subs and also helps you hide from them.
Sonalysts Game Design Notes:
The passive sonar modeling in Dangerous Waters was modified from 688I in an
effort to upgrade the sonar detection and classification performance. Sub
Command models the individual variables in the passive sonar equation:
Passive Sonar Signal Excess = Radiated Noise - Propagation Loss - Interfering Noise - Recognition Differential
1. Radiated Noise is the initial source level of the signal that emanates
from the contact. Broadband radiated noise varies with speed, narrowband
radiated noise does not.
2. Propagation Loss is the amount of loss the source signal sustains as it
travels from the contact to the sonar. Dangerous Waters calculates proploss on
the fly, accounting for the loss due to interaction of the signal with the
acoustic boundaries (surface, bottom, and thermal layer) and the
attenuation loss of the signal as a function of range.
3. Interfering Noise is a combination of background noise (sea state, rain,
shipping density) and self noise (noise emanating from the detecting ship)
that is a function of own ship speed..
4. Recognition Differential is how well a sonar system can differentiate a
signal from the background noise. Dangerous Waters models separate sonar
Recognition Differentials depending on sonar type and model.
All these variables are modeled in Dangerous Waters to determine whether or not
to display a signal on a sonar screen, and how brightly to display the signal.
Broadband radiated noise varies by platform class, and is adjusted for
target speed. Broadband radiated noise values are modeled for
representative frequencies in the 2 kHZ - 4kHZ range.
Narrowband radiated noise is modeled by assigning a narrowband profile to each
appropriate platform - 5 discrete narrowband frequencies. The 5 discrete narrowband
lines range in frequency from 50 Hz - to - 2 kHZ. All U.S. built ships
will have a 60 HZ lines because the U.S. uses 60 cycle electrical
equipment. The rest of the world uses 50 cycle electrical equipment, so
their narrowband profile will have a 50 HZ line.
Low frequency signals propagate through water with much less loss than do
high frequency signals. Therefore, in most cases the best/initial
detection sensor will be the detection of narrowband lines on the towed
array. The window at the top of the Narrowband Station allows the user to
perform a narrowband search. Even though a signal is not visually apparent
in the search window, moving the cursor through all the bearings may
discover a narrowband contact line that will then be displayed in the
middle window. This occurs because the sonar system is able to pull a
signal out of the noise. This is the systems Recognition
Differential. This is the reason why an auto Sonarman will report a
contact that the player does not visually see on the Broadband screen.
The lower frequency lines will be detected first as the range between ships
closes, and the brightness of the lines will depend on the calculated
Signal Excess. The Broadband Station will generally detect after detection
has been made on the Narrowband Station. Towed arrayed broadband will
detect first over the spherical and cylindrical arrays because of it's
lower frequency band and better recognition differential. However,
spherical and cylindrical array detections eliminate the problem with the
ambiguous towed array detection.
The environmental inputs for each mission have a major effect on the sonar
detection performance. The inputs are environmental profile type (surface
duct, convergence zone, bottom limited), bottom type (rock, mud, sand), and
sea state (0-5). The depth of the water is also a major factor. These
inputs are available in the mission editor.