Fiber-Optic Gyros - Northrop Grumman Electronic Systems ...

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Figure 20 shows a van test of an LN-270 system in the San Fernando Valley area of Los Angeles. The top graph shows the path and elevation, while the bottom graph shows the position and altitude errors versus distance traveled. The error limits on the graphs are from Military Performance Specification 71185. Figure 21 shows the LLN-GX, LLN-G1, and the LLN-GY land navigation systems manufactured by Northrop Grumman in Europe. The GX and the G1 are 24235 10 similar and they both have three fiber-optic gyros. The GX uses two level sensors for reduced cost while the G1 uses three accelerometers for higher accuracy. The LLN-GY is the lowest cost of the three. It uses a single fiber-optic gyro sensing rotation about the vertical axis and two accelerometers. Over 1,700 of these systems have been manufactured and delivered. Production is ongoing. Figure 20. LN-270 Van Test Position and Altitude (top) and North, East, and Horizontal Position Errors (bottom). The lines on the top graph show the performance limits in Military Performance Specification 71185.
24235 Figure 21. From left to right, LLN-GX, LLN-G1, and LLN-GY Land Navigation Systems SHIP’S NAVIGATOR PRODUCTS Northrop Grumman manufactures the LFK-95 gyrocompass and reference system for commercial shipping. This was the world’s first marine fiber-optic gyro based gyrocompass and was designed specifically for high speed craft such as hydrofoils. It supports a variety of digital and synchro interfaces for compatibility with a broad range of watercraft. To date 650 systems have been sold to a wide range of customers and production is ongoing. Figure 22 shows the system. Vessels using the LFK-95 system include ships, hydrofoils, and unmanned underwater vehicles. Figure 22. LFK-95 Marine Gyro Compass 11 FIBER OPTIC RATE SENSOR PRODUCTS Northrop Grumman also sells many single axis fiber-optic gyro rate sensors. These gyros are modular and sold either standalone or combined into an IMU. The uFORS line has been in production the longest of any fiber optic rate sensor. To date over 7500 rate sensors and IMUs have been delivered and the product line continues in production. Figure 23 shows the four major subfamilies in the uFORS product line. Each uFORS is a fully contained, single axis, fiber-optic gyro rotation sensor. The uFORS-36 was the first product developed and it had 36° per hour bias accuracy. With the improvement of optical components, the bias accuracy was improved. The uFORS-6U was developed next with a six degrees per hour bias accuracy followed by the uFORS-1 with a one degree per hour bias accuracy. Scale factor repeatability is around 1000 ppm. The units draw two watts of power and have a digital output. The weight of the uFORS-36 and -uFORS-6U is 0.3 lb and their size is 0.8 × 2.5 × 4 inches. The uFORS-36m is miniaturized uFORS-36 with a 36° per hour bias accuracy for size critical applications. Another single axis rate sensor product is the FOG-200. It is available as a single axis assembly that is fully self-contained as shown in the picture on the left side of Figure 24. The rate sensing element can be packaged remotely from the electronics for special applications as shown in the middle picture of Figure 24 for a two axis rate sensor. The right-hand picture shows a three axis, remote sensing, rate sensor package.
Page 1 and 2: 24235 Fiber-Optic Gyros: The Vision
Page 3 and 4: ABSTRACT Over thirty five years hav
Page 5 and 6: A land navigation version of the LN
Page 7 and 8: The LN-200 is used in a wide variet
Page 9 and 10: INS PRODUCTS 24235 Figure 10. The I
Page 11: Figure 16. LTN-101E Navigation and
Page 15 and 16: REFERENCES 1 G. Sagnac, “L’ethe

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