G-1: What type of motion sensors are manufactured by Systron Donner Inertial?

Systron Donner Inertial manufactures a complete line of micromachined, solid-state gyroscopes and inertial subsystems for automotive, commercial/industrial, and aerospace & defense applications. Our family of quartz inertial sensors use a one piece, micromachined inertial sensing element to measure angular rotational velocity or linear acceleration. These sensors produce an output signal proportional to the rate of rotation or acceleration sensed.

G-2: How are SDI’s inertial sensors produced?

SDI’s unique quartz inertial sensors are micromachined using photolithographic processes, and are at the forefront of MEMS (Micro ElectroMechanical Systems) technology. These processes are similar to those used to produce millions of digital quartz watches each year. The use of piezoelectric quartz material simplifies the sensing element, resulting in exceptional stability over time and temperature, and exceptional reliability and durability.

G-3: How do micomachined quartz rate sensors compare to other gyroscope technologies that are currently available?

SDI’s innovative solid-state gyroscopes utilize a one-piece sensing element which is micromachined from pure crystalline quartz. Unlike traditional mechanical gyroscopes which are mechanically complex, contain hundreds of individual precision parts, and have a limited life, SDI’s quartz sensors feature a monolithic sensing element with no known modes of wearout.

SDI quartz gyroscopes have many advantages over other solid-state gyroscope technologies. First, their construction is extremely simple...the sensing element is just one piece! Fiber Optic Gyroscopes (FOG) and Ring Laser Gyroscopes (RLG) tend to be much more complex, time consuming to build, and considerably more expensive. The sensing elements of SDI’s quartz gyroscopes can be mass produced at a very low recurring cost using methods similar to those employed to fabricate millions of quartz references for watches each year.

G-4: What is the MTBF (Mean Time Between Failure) of SDI quartz gyroscopes?

SDI’s quartz gyroscopes are micromachined from pure crystalline quartz. Since there are no moving parts, and hence no wearout modes, they feature an unlimited life.

Standard MIL-HDBK-217 MTBF calculations, depending upon the environment used, are typically better than 400,000 hours for a single axis sensor. In commercial aircraft applications, SDI’s quartz gyroscopes have accumulated over 1,500,000 hours of operation without a single failure. In US Navy shipboard antenna stabilization applications, SDI’s quartz gyroscopes have accumulated over 2,000,000 hours of continuous operation without a single failure.

In contrast, some conventional mechanical gyroscopes must be replaced after only a few thousand hours of operation!

Q-1: What types of applications has the Model QRS11 been qualified for?

The Model QRS11 is currently being used on literally hundreds of demanding aerospace applications. For example, it is formally qualified for airplane/helicopter flight control, missile flight control, aircraft instrumentation, aircraft/shipboard antenna stabilization and airborne countermeasure systems. Some of these usages are highlighted in our applications section.

In its off-the-shelf configuration, the Model QRS11 is also qualified for space applications. The Model QRS11 has been used as a COTS component for the Space Shuttle Astronauts Backpack (Shuttle Mission STS 64), and more recently, as the directional (yaw) gyro on the NASA/JPL Mars Rover.

Q-2: What is the primary difference between the Standard and High Performance versions of the Model QRS11?

Both versions are the same basic high reliability Quartz Rate Sensor. The primary difference between the "standard" performance and the "high performance" versions is the maximum possible change in bias offset (DC) over the operating temperature range of -40°C to +80°C. For example, the bias offset of a Standard version of a Model QRS11 with a full scale range of ±100°/second could change by up to 1.8°/second over the operating temperature range. For the High Performance version, the maximum possible change would be <=0.35°/second.

Actual QRS11 performance, however, is typically well within the numbers cited above.

Q-3: What type of Self-Test features are available?

The Model QRS11 Quartz Rate Sensor incorporates a dual self-test facility to determine the health of the unit, both for monitoring and for failure detection.

An individual "Rate Valid" signal is produced by the drive system of each QRS. That signal provides a continuous monitor indicating that the QRS sensor drive system is functioning normally. The Rate Valid signal is similar to that used in older spinning-wheel gyro systems, one called a "Spin-Motor Rotation Detector" (or SMRD), which indicated the wheel was running normally.

To provide a definitive test of the remainder of the signal processing circuitry in the QRS, an Initiated Built-in-Test (BIT) is provided. It commands a specific change of output from the activated channel, and successful completion indicates that the entire signal chain within the QRS has integrity and is performing normally.

Q-4: What gyro performance class is the Model QRS11?

Systron Donner Inertial’s gyroscopes are often referred to as "tactical grade", which means they are ideally suited for aircraft/missile control and damping systems, short-term guidance of tactical missiles and mortar munitions, and as an adjunct for GPS navigation systems.

Q-5: Does the QRS have overrange capability?

The Model QRS11 has built-in overrange capability of a minimum of 120% of the stated full scale output. For example, the output signal of a Model QRS11 with a ±100°/second full scale output, will remain perfectly linear up to at least ±120°/second. At some point above ±120°/second, the output signal will hit its limit, and stay there for all angular rates above the point at which the output became saturated. During this time, the output signal will remain stable and will not fold back. Extremely high angular rates of 5,000 to 10,000 degrees per second (or more) will not damage the Model QRS11; the output will simply remain saturated. When the angular rate drops below the point of saturation, the output signal will once again indicate the true angular rate.

Q-6: Are there any standard options available?

Yes. The Model QRS11 can be ordered with various options to suit the individual needs of your application. Standard options include an extended temperature range of -50°C to 95°C, wider bandwidths of 100 or 150 Hz, a low-noise version (about 1/2 the standard output noise specification) , and the attachment of flying leads.

Q-7: Can the Model QRS11 be operated beyond its operating temperature range?

Yes. The QRS11 can safely be operated within the stated storage temperature range of -50°C to +100°C, however, Systron Donner Inertial cannot guarantee full compliance with the published specifications beyond the normal operating temperature range.

GC-1: What is the difference between the -102 and -103 configurations listed on the GC II data sheet?

The GC II is available in two basic configurations to suit your needs for a high reliability commercial/industrial grade angular rate sensor. The -102 version operates from a single-sided power supply of +9 Vdc to +18 Vdc, and is most useful for applications which use battery power (also see POWERSAVE Mode below). During normal operation, the -102 versions uses less than 40 mA.

The -103 version operates from two-sided power; ±9 Vdc to ±18 Vdc.

Both versions feature internal power regulation.

GC-2: What is POWERSAVE Mode?

POWERSAVE Mode is a feature of the -102 version. By applying 5 Vdc ±1 Vdc to the POWERSAVE input, the internal amplifier circuitry to the QRS is disconnected from the power supply, and the maximum input current decreased from <40mA to <20mA. The tuning fork sensing element continues to operate during POWERSAVE Mode.

GC-3: Does the Gyrochip^® II have Built-in-Test (BIT) Capability?

Yes. Built-in-Test is activated by grounding Pin 7 causing a step increase in rate output (Pin 5) of 2.8 to 3.0 Vdc for the -102 version, and 1.0 to 1.5 Vdc for the -103 version. This verifies the Gyrochip^®'s electronics are operating normally. Note that when Pin 7 is grounded, the BIT output (step change) is superimposed on the true rate output signal of the Gyrochip^® .

H-1: What are the primary applications the Horizon is designed for?

The Gyrochip^® Horizon is a low-cost single range (±90°/s) angular rate sensor intended primarily for commercial/industrial OEM applications. Typical applications include the stabilization of airborne/shipboard antenna stabilization systems, GPS augmentation for vehicle location systems, manufacturing automation, precision farming, robotics, etc.

H-2: What is the purpose of the Voltage Reference pin (Pin #3)?

The voltage reference pin (Pin #3) provides a stable 2.5 Vdc reference output which allows for differential monitoring of the Rate Output signal (Pin #2).

M-1: I don’t need all six Degrees-of-Freedom; can I order the MotionPack^® with less than 6 sensors?

Yes. The MotionPack^® offers total flexibility in which channels (or axes) of angular rate and linear acceleration are included in the delivered product. In addition to the complete 6 DoF configuration, the MotionPack^® can be ordered with one, two or three axes of angular rate sensors and linear accelerometers. For more details and ordering information, please contact the factory at (925) 671-6400, or e-mail us at sales@systron.com.

M-2: What other options are available?

The MotionPack^® is available with several angular rate sensor and linear accelerometer full scale ranges to suit your motion measurement needs. The angular rate sensor used within the MotionPack^® is Model QRS11, which has other options available. See individual product data sheet for details.