Improvements may also be found by fully enclosing the gyro in a metal enclosure, minimising any 'metal detector' or field effects. Minimising temperature variation over measurement cycle will improve accuracy, either by thermal shielding or provision of thermal mass. However, the optimum averaging time may be longer than the user can accept and we have typically used 15s averaging for each compass point (90deg separation) measurement. We average every 10 samples to produce a data set at 1KHz.Īnalysis of the resulting data using Allan Variance techniques will determine the optimum averaging time. Again the CRS39-03 is sampled differentially (Rate and Ref). Actual sampling at the sensor end is around 192KHz. (b) In our IMUs, we use 24 bit sigma delta ADCs, outputting sampled data at 10 kHz. This data is then analysed for AV and Noise. We then average every set of 10 samples to produce data at 1 KHz. We sample the CRS39-03 fully differentially (Rate and Ref), at 10KHz, without any anti-aliasing filters. ![]() (a) In our test chambers we use a16 bit (successive approximation register ADC) National Instruments card. Two sampling schemes that we would recommend are: ![]() Sampling and averaging of the gyro rate data, guided by Allan Variance analysis, is key to getting the best out of CRS39 and to allow the earth rate signal to be drawn out of the noise. Capacitive (VSG4) Line - 2004 to present. ![]() Piezoelectric (VSG5) Line - 2010 to present.Inductive (VSG3) Line - 1999 to present.
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