Winston
Lorenzo von Matterhorn
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This Isn't A Sci-Fi Prop, It's A Doomsday Navigator For America's Deadliest Cold War ICBM
The Peacemaker missile's navigation suite featured the most precise and complex self-contained gyro system ever built. It had 19,000 individual parts.
8 Oct 2019
https://www.thedrive.com/the-war-zo...-navigator-for-americas-biggest-cold-war-icbm
The AIRS (Advanced Inertial Reference Sphere) is the most accurate inertial navigation (INS) system ever developed, and perhaps marks the end of a long process of continuous refinement of INS technology.
This immensely complex and expensive INS unit has "third generation" accuracy as defined by Dr. Charles Stark Draper, the leading force in the development of hyper-accurate inertial guidance. This translates into INS drift rates of less than 1.5 x 10^-5 degrees per hour of operation. This drift rate is so low that the AIRS contributes on the order of only 1% of the Peacekeeper missile's inaccuracy, and is thus effectively a perfect guidance system (i.e. a zero drift rate would not measurably improve the Peacekeeper's performance).
Very little of the precision of this guidance system is even exploited during a ballistic missile flight, it is mostly used simply to maintain guidance system alignment on the ground during missile alert without needing an external reference through precision gyrocompassing. Most ICBMs require an external alignment system to keep the INS in synch with the outside world prior to launch. The AIRS is probably as good as any INS for ICBM guidance needs to get.
The penalty for this extreme level of accuracy is tremendous complexity and cost. The AIRS has 19,000 parts. In 1989 a single accelerometer used in the AIRS (there are three) cost $300,000 and took six months to manufacture.
There are very few applications requiring such precise guidance and independence from external references. In fact, beyond ICBM guidance, none have been identified. If the requirement for complete autonomy is eliminated, extreme guidance accuracy is available at a small fraction of its cost and weight. For example, the advent of satellite positioning systems like GPS (Global Positioning System) and GLONASS, which permit centimeter-level accuracy over unlimited periods of operation with only a light inexpensive receiver. NASA spcecraft require extreme guidance precision, but use external navigation cues to obtain it. Even new nuclear weapon guidance programs have shown a willingness to sacrifice autonomy for cost and weight. The proposed BIOS (Bomb Impact Optimization System), a glide-bomb adaptation of the B-61, has proposed using GPS for guidance instead of an INS. Given the competition from advanced external reference-based approaches, INS technology has probably reached the end of the line as far as accuracy goes.
So yeah, this thing was really something. In fact, some would argue it was among the most incredible pieces of technology that came out of the Cold War. AIRS was critical in lowering the circular error probable (CEP, aka accuracy) of the missile down to 40 meters. The Minuteman III, which remains in service today, has a CEP of roughly six times that. The very idea that an ICBM could be so accurate was a major factor in bringing the Peacekeeper to life in the first place under what was then known as the MX program.
The Peacemaker missile's navigation suite featured the most precise and complex self-contained gyro system ever built. It had 19,000 individual parts.
8 Oct 2019
https://www.thedrive.com/the-war-zo...-navigator-for-americas-biggest-cold-war-icbm
The AIRS (Advanced Inertial Reference Sphere) is the most accurate inertial navigation (INS) system ever developed, and perhaps marks the end of a long process of continuous refinement of INS technology.
This immensely complex and expensive INS unit has "third generation" accuracy as defined by Dr. Charles Stark Draper, the leading force in the development of hyper-accurate inertial guidance. This translates into INS drift rates of less than 1.5 x 10^-5 degrees per hour of operation. This drift rate is so low that the AIRS contributes on the order of only 1% of the Peacekeeper missile's inaccuracy, and is thus effectively a perfect guidance system (i.e. a zero drift rate would not measurably improve the Peacekeeper's performance).
Very little of the precision of this guidance system is even exploited during a ballistic missile flight, it is mostly used simply to maintain guidance system alignment on the ground during missile alert without needing an external reference through precision gyrocompassing. Most ICBMs require an external alignment system to keep the INS in synch with the outside world prior to launch. The AIRS is probably as good as any INS for ICBM guidance needs to get.
The penalty for this extreme level of accuracy is tremendous complexity and cost. The AIRS has 19,000 parts. In 1989 a single accelerometer used in the AIRS (there are three) cost $300,000 and took six months to manufacture.
There are very few applications requiring such precise guidance and independence from external references. In fact, beyond ICBM guidance, none have been identified. If the requirement for complete autonomy is eliminated, extreme guidance accuracy is available at a small fraction of its cost and weight. For example, the advent of satellite positioning systems like GPS (Global Positioning System) and GLONASS, which permit centimeter-level accuracy over unlimited periods of operation with only a light inexpensive receiver. NASA spcecraft require extreme guidance precision, but use external navigation cues to obtain it. Even new nuclear weapon guidance programs have shown a willingness to sacrifice autonomy for cost and weight. The proposed BIOS (Bomb Impact Optimization System), a glide-bomb adaptation of the B-61, has proposed using GPS for guidance instead of an INS. Given the competition from advanced external reference-based approaches, INS technology has probably reached the end of the line as far as accuracy goes.
So yeah, this thing was really something. In fact, some would argue it was among the most incredible pieces of technology that came out of the Cold War. AIRS was critical in lowering the circular error probable (CEP, aka accuracy) of the missile down to 40 meters. The Minuteman III, which remains in service today, has a CEP of roughly six times that. The very idea that an ICBM could be so accurate was a major factor in bringing the Peacekeeper to life in the first place under what was then known as the MX program.
