Inertial Measurement Unit (IMU) ISIS-IMU (Rev. C) Features Fully compensated Inertial Measurement Unit (IMU) DC in digital output Most cost effective IMU - Lowest cost 6 degree of freedom IMU in its performance class High angular rate capability (upto 3,000 /sec) High acceleration (upto 500 g) Inherent high ruggedness Small, lightweight and Low power consumption Comprised of Solid-State sensors (no moving parts) High MTBF (>10,000 hours) Description ISIS-IMU is a six-degree of freedom inertial mesurement unit designed for commercial use. ISIS-IMU achieves unparalleled price/performance and inherent ruggedness. It is well suited for medium accuracy and high dynamic environments, where small size (2.8 x 3.0 x 2.3 ), lightweight (nominal weight is less than 0.8 lb.), and low power consumption (less than 6W @ +28V DC) are demanded. (E.g. GPS integration, etc.). It consists of three RRS75 (solid state rate sensors) and three solid state accelerometers. This system incorporates a sigma-delta digitizer and a 16-bit microprocessor to provide fully compensated digital (RS232 or RS422) outputs. ISIS-IMU can be configured to match a customer s scale factor and bandwidth requirements. Inertial Science, Inc. can readily custom tailor this IMU to meet specific application requirements on a special order basis for commercial use. Applications AHRS - Attitude Heading Reference System Vertical Reference System GPS/INS Applications Stabilization Application Control #: Z271590
TECHNICAL SPECIFICATIONS Performance (Standard Unit) Acceleration Parameter Units VRU IMU Capability Parameters Units ISIS-IMU (Rev. C) Capability Range g +/- 20 unit Short Term Bias Stability mg +/- 2 Scale Factor Accuracy Percent <0.2% full scale (2000ppm) Nonlinearity Percent <0.5% full scale (5000ppm) Random Walk m/s/hr ½ < 0.1 Axis Misalignment mrad < 2 Bandwidth Hz >=30 Data Resolution mg 1 Angular Rates r Units VRU IMU Capability Parameters Units ISIS-IMU (Rev. C) Capability Range Deg/sec +/- 90 unit Short Term Bias Stability Deg/sec < 0.01 Long Term Bias Stability Deg/sec RMS < 1 Scale Factor Accuracy Percent < 0.2% full scale (2000 ppm) Non-linearity Percent < 0.2% full scale (2000 ppm) Random Walk Deg/hr ½ < 0.5 Thermal Drift Deg/sec <0.1 peak to peak ( -20C to +55C) G-Sensitivity Deg/sec/g <0.02 Bandwidth Hz >=30 Data Resolution Arc seconds/second 2 ENVIRONMENTAL SPECIFICATIONS Vibration Operational: Non-Operational: Shock Operational Shock: Non-operational Shock: 4 g RMS, 20 to 2kHz random 6 g RMS, 20 to 2kHz random 30g /11 ms/ 6 times per direction 100g / 11ms/ 1 time per direction Operating Temperature -40 deg C to +70 deg C. (power-up and output data). Calibrated Temperature -20 deg C to +50 deg C. Storage Temperature -55 deg C to +85 deg C.
Connector and Pin-outs The data and power interface to the ISIS-IMU shall be via a 26 pin High Density D type male connector. Pin # Description Remarks Note 1 rate x analog output +/- 4Vdc Optional 2 rate y analog output +/- 4Vdc Optional 3 rate z analog output +/- 4Vdc Optional 4 accel x analog output +/- 4Vdc Optional 5 accel y analog output +/- 4Vdc Optional 6 accel z analog output +/- 4Vdc Optional 7 Gnd 8 Gnd 9 Gnd 10 external RESET Active low TTL 11 Timing output Time marker output Factory Use 12 Timing input Time marker input Factory Use 13 Mode output System mode Factory Use 14 Reserved for RS422 Optional 15 Reserved for RS422 Optional 16 RS-232 TX data Transmit sensor data 17 RS-232 RX data Receive command 18 RS-232 Common 19 + Extra Power Input No Connection 0.21A 20 +28 VDC input +28V (+/- 10%) 0.23A @ 28V 21 Gnd 22 Gnd 23 28 VDC ground Return 24 - Extra Power Input No Connection 25 Vpp Programming power input Future use 26 PRGM Programming command Factory use
GENERAL SPECIFICATIONS Size 2.8 x 3.0 x 2.3 Nominal Weight < 0.8 lb. Supply Voltage 9V to 36V DC (user selectable) Nominal Input Power < 6W @ (+28V DC) Misalignment Angle < 2 mrad MTBF >10,000 hours Baud rate : 115.2 KB Frame rate : 100 frames/sec Protocol : 1 start bit (0), 8 data bit (LSB first), 1 stop bit (1), no parity Byte # Description Remarks 1 7E(hex) Header 2 slow data 1Hz average data 3 rate x low nominal scale factor 0.003 deg/sec/bit 90 deg/sec = 30000 bit 4 rate x high (2 s complement) 5 rate y low nominal scale factor 0.003 deg/sec/bit 90 deg/sec = 30000 bit 6 rate y high (2 s complement) 7 rate z low nominal scale factor 0.003 deg/sec/bit 90 deg/sec = 30000 bit 8 rate z high (2 s complement) 9 accel x low nominal scale factor 0. 667 mg/bit 20 g = 30000 bit 10 accel x high (2 s complement) 11 accel y low nominal scale factor 0.667 mg/bit 20 g = 30000 bit 12 accel y high (2 s complement) 13 accel z low nominal scale factor 0.667 mg/bit 20 g = 30000 bit 14 accel z high (2 s complement) 15 counter 1 upcount/frame (0 ~ 99) 16 check sum exclusive-or byte 1 15
X Axis Gyro Accel X Axis Digitizer ISIS-IMU (Rev. C) Block Diagram (optional) Analog Output Y Axis Gyro Accel Y Axis Digitizer Micro Computer RS232 Serial Data +5V Z Axis Gyro Accel Z Axis Digitizer -5V DC/DC Converter +9V ~ 36V DC User Selectable
Trouble shooting and Repair No user accessible components. Authorized factory personnel must perform all repairs. Contact Inertial Science, Inc. Handling Please handle with extreme care. ISIS-IMU contains mechanically delicate instruments rate sensors and accelerometers. Any shock in excess of 100 g 10 msec. may cause permanent shifting in the calibration parameters or mechanical damage to the instrument. Quality Assurance and Warranty Quality is an integral part of the design cycle and during fabrication and test of the product at Inertial Science, Inc. In other words, we do not try to inspect in the quality, but have it inherent to the design and built. The following are the steps in the Quality Assurance process: 1. During the assembly and integration a traveler accompanies the hardware. This traveler covers all electronics and mechanical assemblies; all wiring; and integration tests. Both the assembler and inspector sign for each step. 2. An extensive Acceptance Test Procedure (depending on cutomers requirement) is performed prior to shipment. The traveler and ATP data are filed in our system book. 3. A configuration lists and certificate of conformance are supplied with each system. 4. Software verification. The software used for ISIS-IMU has been verified by simulation, ISI in-house tests. Our warranty is for one year after the shipment from ISI s facility based on customers reasonable usage. ISI intends to resolve any problems occuring during this warranty in an essential, effective, and timely manner. 3533 Old Conejo Road Suite 104, Newbury Park, U.S.A. (805) 499-3191 or FAX (805) 498-4882 http://www.inertialscience.com info@inertialscience.com Specification are subject to change without notice. Copyright 1999, Inertialscience, Inc. All Rights Reserved.