Welcome to Silicon Sensing

Silicon Sensing Systems has unrivalled expertise in the design and manufacture of high performance inertial measurement sensors and systems. We constantly push the boundaries of what is possible through the use of patented silicon MEMS structures, which are manufactured in our own foundry in Japan. Assessment of our latest gyro sensors and systems show that, in critical areas such as bias instability and angle random walk, these high performance devices deliver performance equivalent to far larger, heavier and more expensive fibre optic-based units. The success of our inertial measurement technology is evident in the tens of million sensors we have delivered to customers since we were established over 20 years ago.

With our products in use on the most hazardous terrains and in the most extreme conditions, Silicon Sensing has a wide range of sensors and systems to meet your specifications at any time, in any conditions, on any terrain. To find out more, see below or click the product image opposite. To talk to us simply submit the brief form below, and we will be in touch.

Product description

Compact High-performance MEMS Gyro

A single axis gyroscope, providing outstanding stability with low noise.

The unit has comparable bias characteristics to FOG (fibre-optic gyros) and DTG (dynamically-tuned gyros), and is available in five dynamic ranges. The new CRH03 offers uprated performance over the highly successful CRH02 gyro due to improvements in both MEMS and electronics.

What is the purpose of the FRQ and TMP outputs on the CRS39, CRS09 and CRH02 sensors?

Basically, our gyroscopes use a silicon (MEMS) ring which is setup and controlled to vibrate in a precise manner. When the gyro is rotated, the resonance pattern changes; the way it changes being proportional to the rotation rate applied to the gyro. Electronics around the ring control the resonance of the ring and also sense the motion of the ring.

When the gyro is subjected to changes of temperature, the bias and scale factor of the gyroscope can change.

We therefore provide two outputs which can be used to sense the change of temperature.

A temperature sensor is included to sense the temperature of the electronics within the gyroscope.

The ring's resonating frequency is also sensed and output as a digital signal. The frequency of the ring is proportional to the temperature of the ring. The frequency of the ring is proportional to the temperature of the ring. This ring frequency is nominally 14 KHz, with the FRQ signal being two times this frequency, that is , nominally 28 KHz. The frequency changes with temperature at -0.76 Hz/degC.

By subjecting the gyroscope to a changing temperature, it is possible to measure the errors (bias and scale factor) of the gyroscope against the frequency output and the temperature sensor output. Using look up tables or fitting polynomials to these errors, it is possible to compensate for the errors, by subtracting the derived error from the output of the gyroscope.

The temperature sensors will be more responsive to changes in temperature of the environment than frequency because of the longer thermal path to the MEMS ring. Equally, in a highly (angular) dynamic environment where the ring will be heated by the nulling action of the secondary loop, the frequency output will be more responsive. In a fairly stable environment, where the temperature across the whole of the gyroscope is stable, then both methods are equivalent.

Can you provide more information about the FRQ output from CRS09, CRS39 and CRH02?

In general terms, the simplest method for temperature compensation is to use the on-board temperature sensor as the first step. This can be regarded as the primary (coarse) thermal error correction. A further refinement of thermal compensation can be achieved using the ring frequency (FRQ) since this is a measure of the temperature of the ring.

At normal room temperature (+25degC) operation, the FRQ signal is between 27.4kHz and 28.6kHz. The ring gets 'stiffer' as the temperature drops and thus the frequency will increase, and vice versa. The temperature coefficient of the ring is between -0.82 and - 0.70Hz/degC (nominally -0.76Hz/degC). So, if the value of FRQ drops by, say, 7.6Hz then you can assume the ring temperature has increased by 10degC to +35degC [-7.6 / -0.76 = +10degC]. The silicon ring is supported on a glass substrate surrounded by an inert gas inside a sealed metal can. So it is quite well insulated, thus there is a lag between a change in the ambient temperature and the temperature (and thus frequency) of the ring. The temperature sensor on the board reacts quicker to the ambient temperature fluctuations.