China testing hypersonic weapon with intercontinental range, says USNORTHCOM commander

[Zsari]

Ok pls tell how can the missile find the target? How can the missile even know if it is heading to a correct direction let’s say Miami or Wuhan?

Never heard of ballistic trajectory and inertial guidance?

 

[FairAndUnbiased]

Ok pls tell how can the missile find the target? How can the missile even know if it is heading to a correct direction let’s say Miami or Wuhan?

by your logic guns are useless, since bullets have no external guidance.

 

[Paul2]

Never heard of ballistic trajectory and inertial guidance?

Ballistic is easy to guide with INS, especially outside of atmosphere.

A maneuvering cruise missile that vibrates like hell? No

 

[Zsari]

Ballistic is easy to guide with INS, especially outside of atmosphere.

A maneuvering cruise missile that vibrates like hell? No

The stated HGV is a ballistic missile. It does enter atmosphere during its gliding state, but its inertial should be far more pronoun than any other forces.

 

[Viet]

Never heard of ballistic trajectory and inertial guidance?

Ok you mean firing a missile is like doing a slingshot?

 

[j20blackdragon]

The key word here is intercontinental.

This is basically the Chinese Avangard, i.e. an ICBM-boosted HGV traveling at Mach 20+.

There is no defense against such a weapon.

RF countermeasures such as jamming or even theoretical high-power microwave weapons won't work because they require line of sight and a HGV is gliding below the radar horizon for the vast duration of its flight.

Below the radar horizon means you have no early warning.

Without radar-tracking data, you have no way to extrapolate the range, heading, and airspeed of the incoming HGV, i.e. you can't possibly calculate the flight path for interception.

During tests, the Russian Avangard reached Mach 27, or roughly 33,000 kilometres per hour.

33,000 kilometres per hour is 550 kilometres per minute.

The SAMPSON AESA radar on the British Type 45 destroyer has a range of 400 km.

 

[Zsari]

Ok you mean firing a missile is like doing a slingshot?

Just Google INS.

An inertial navigation system (INS) is a navigation device that uses a computer, motion sensors (accelerometers) and rotation sensors (gyroscopes) to continuously calculate by dead reckoning the position, the orientation, and the velocity (direction and speed of movement) of a moving object without the need for external references.

 

[FairAndUnbiased]

Just Google INS.

An inertial navigation system (INS) is a navigation device that uses a computer, motion sensors (accelerometers) and rotation sensors (gyroscopes) to continuously calculate by dead reckoning the position, the orientation, and the velocity (direction and speed of movement) of a moving object without the need for external references.

he doesn't know or care.

 

[Viet]

Just Google INS.

An inertial navigation system (INS) is a navigation device that uses a computer, motion sensors (accelerometers) and rotation sensors (gyroscopes) to continuously calculate by dead reckoning the position, the orientation, and the velocity (direction and speed of movement) of a moving object without the need for external references.

That’s not new!
It’s some sorts of estimations and guessing.

I assume the Pla makes sure the missiles hit targets in the US not cities in China.

The key word here is intercontinental.

This is basically the Chinese Avangard, i.e. an ICBM-boosted HGV traveling at Mach 20+.

There is no defense against such a weapon.

RF countermeasures such as jamming or even theoretical high-power microwave weapons won't work because they require line of sight and a HGV is gliding below the radar horizon for the vast duration of its flight.

Below the radar horizon means you have no early warning.

Without radar-tracking data, you have no way to extrapolate the range, heading, and airspeed of the incoming HGV, i.e. you can't possibly calculate the flight path for interception.

During tests, the Russian Avangard reached Mach 27, or roughly 33,000 kilometres per hour.

33,000 kilometres per hour is 550 kilometres per minute.

The SAMPSON AESA radar on the British Type 45 destroyer has a range of 400 km.

Can you explain how it works?
Space shuttle re enters the atmosphere at Mach 25, thanks to Earth gravity and thin atmosphere.
How can the missile sustain a long hypersonic flight at low attitude given the dense atmosphere with high friction?

 

[FairAndUnbiased]

That’s not new!
It’s some sorts of estimations and guessing.

Can you explain how it works?
Space shuttle re enters the atmosphere at Mach 25, thanks to Earth gravity and thin atmosphere.
How can the missile sustain a long hypersonic flight at low attitude given the dense atmosphere with high friction?

why do you ask questions that you aren't interested in the answers to and don't care to understand?

 

[Viet]

why do you ask questions that you aren't interested in the answers to and don't care to understand?

Who tells you I am not interested of answers? Till now you particularly respond with bs, while others only post wiki articles. As if I talk to machines.

 

[FairAndUnbiased]

Who tells you I am not interested of answers? Till now you particularly respond with bs, while others only post wiki articles. As if I talk to machines.

you don't need external guidance in flight if 1. the target doesn't move 2. you know your initial position 3. you know your trajectory. if you know your initial position and all parameters of your trajectory (velocity and acceleration - hence, you know your position at all times) then you know what your target is. this is called dead reckoning.

if your accelerators have a linear dynamic range large enough to measure all possible accelerations on your projectile , dead reckoning declines in accuracy with passing time due to random drift of accelerometers - however, a hypersonic projectile is in flight for only 30 minutes, so this drift doesn't really matter.

 

[gambit]

you don't need external guidance in flight if 1. the target doesn't move 2. you know your initial position 3. you know your trajectory. if you know your initial position and all parameters of your trajectory (velocity and acceleration - hence, you know your position at all times) then you know what your target is. this is called dead reckoning.

You guys tossed the initials INS around as if you know what you are talking about. You do not.

Inertial guidance or INS is essentially dead reckoning. Or a guess.

Ok pls tell how can the missile find the target? How can the missile even know if it is heading to a correct direction let’s say Miami or Wuhan?

The question is technically correct. A ballistic missile using only INS (dead reckoning) do not and cannot 'find' anything. To 'find' something begs the question of sensor(s) in the first place. Even a blind man using a cane is more capable than an INS at finding something because the cane produces external based feedback when it encounters something.

If the target is fixed and if the guessing mechanism is sophisticated enough, then the INS will guide the missile to the intended location. But geographical location is not necessarily the same as the target. The target could be stationary ATOP a geographical point and moves when convenient. In this case, if the target moved then the ballistic missile using only INS guidance will hit the ground where it estimated it should be.

Inertial navigation is NOT sensor.

if your accelerators have a linear dynamic range large enough to measure all possible accelerations on your projectile , dead reckoning declines in accuracy with passing time due to random drift of accelerometers - however, a hypersonic projectile is in flight for only 30 minutes, so this drift doesn't really matter.

Not true.

What you said is not true, not because of the accelerometer's dynamic range, but because of AERODYNAMICS on the body.

https://history.nasa.gov/SP-60/ch-5.html
https://history.nasa.gov/SP-367/chapt7.htm

The bottom line, which came from NASA, is that with hypersonic flight, aerodynamic forces on the body produces greater effects in smaller amount of time than in subsonic flight. Thirty minutes are plenty enough time for any structural issues like longitudinal flex in the fuselage to compound and destroy the vehicle. But if this worst case scenario does not occur, then the INS will fail to deliver the vehicle to its intended location precisely because of the flight controls system's constant high dynamic range compensation in all flight axes. Basically, what I said is that structural flex at hypersonic speed deviate the missile one way, the flight controls system attempts to compensate to the other way, but because the INS components are of shiddy quality, each compensation is larger than necessary. Think of oversteering, for example.

In a hypersonic vehicle, the flight controls system must be of greater sophistication in terms of sensitivity and fine grain controls of all flight controls surfaces. Same goes for the INS.

I did warned you guys to be careful when you treads into these matters.

 

[FairAndUnbiased]

You guys tossed the initials INS around as if you know what you are talking about. You do not.

Inertial guidance or INS is essentially dead reckoning. Or a guess.

Ok pls tell how can the missile find the target? How can the missile even know if it is heading to a correct direction let’s say Miami or Wuhan?

The question is technically correct. A ballistic missile using only INS (dead reckoning) do not and cannot 'find' anything. To 'find' something begs the question of sensor(s) in the first place. Even a blind man using a cane is more capable than an INS at finding something because the cane produces external based feedback when it encounters something.

If the target is fixed and if the guessing mechanism is sophisticated enough, then the INS will guide the missile to the intended location. But geographical location is not necessarily the same as the target. The target could be stationary ATOP a geographical point and moves when convenient. In this case, if the target moved then the ballistic missile using only INS guidance will hit the ground where it estimated it should be.

Inertial navigation is NOT sensor.


Not true.

What you said is not true, not because of the accelerometer's dynamic range, but because of AERODYNAMICS on the body.

https://history.nasa.gov/SP-60/ch-5.html
https://history.nasa.gov/SP-367/chapt7.htm

The bottom line, which came from NASA, is that with hypersonic flight, aerodynamic forces on the body produces greater effects in smaller amount of time than in subsonic flight. Thirty minutes are plenty enough time for any structural issues like longitudinal flex in the fuselage to compound and destroy the vehicle. But if this worst case scenario does not occur, then the INS will fail to deliver the vehicle to its intended location precisely because of the flight controls system's constant high dynamic range compensation in all flight axes. Basically, what I said is that structural flex at hypersonic speed deviate the missile one way, the flight controls system attempts to compensate to the other way, but because the INS components are of shiddy quality, each compensation is larger than necessary. Think of oversteering, for example.

In a hypersonic vehicle, the flight controls system must be of greater sophistication in terms of sensitivity and fine grain controls of all flight controls surfaces. Same goes for the INS.

I did warned you guys to be careful when you treads into these matters.

I'm not anywhere close to an expert at this. However, the question wasn't a specialist question. It was a layman question that asked "if there is no sensor, how does a rocket find a stationary target". The answer is, as you said, INS can be pre-programmed to hit a certain geographic location through dead reckoning. If the target is stationary then it works.

This works for ballistic missile warheads. Their aerodynamics are simple: with a blunt shape and no control surfaces, they will just fly more or less ballistically if designed correctly. This can all be known before flight.

In controlled hypersonic flight, there are additional challenges, as you stated, due to INS possibly overcompensating, or because of structural failure. However, I don't think these challenges are physically impossible to solve. These problems are also not solvable by external guidance, which is what the original poster asked.

 

[Paul2]

I'm not anywhere close to an expert at this. However, the question wasn't a specialist question. It was a layman question that asked "if there is no sensor, how does a rocket find a stationary target". The answer is, as you said, INS can be pre-programmed to hit a certain geographic location through dead reckoning. If the target is stationary then it works.

This works for ballistic missile warheads. Their aerodynamics are simple: with a blunt shape and no control surfaces, they will just fly more or less ballistically if designed correctly. This can all be known before flight.

In controlled hypersonic flight, there are additional challenges, as you stated, due to INS possibly overcompensating, or because of structural failure. However, I don't think these challenges are physically impossible to solve. These problems are also not solvable by external guidance, which is what the original poster asked.

Ballistic requires only 2 points measured along the way to predict the hit point, that's what makes it easy.

Usually one post boost, and an apex correction.

Now imagine doing them every time an external force acts on a vehicle. You have to do them pretty much continuously