IMU bias stability spec comparison
Spec-sheet comparison of bias stability language in public reports.
Heritage notes kept in view
Features Hardware/software for precision roll, pitch, heading and navigation Complete inertial navigation solution at IMU data rate (e.g.
200Hz, WGS-84) Initial heading and leveling alignment accomplished with Kalman Filter In-air alignment capability (re-start) Navigator calibrated with Multi-State Kalman filter using GPS observations UTC event timing to 1 microsec System Description Kearfott KI-4901 Inertial Measuremment Unit NovAtel ProPak-LB GPS system using Omnistar to achieve <0.2 m accuracy in real time QNX operating system Standard RS-422 IMU interface with data validity interrupt PADS/C, Ethernet controller Data can be collected for Post processing Removable I/O panel Swappable 1-36 VDC Volt Lambda Power Supply.
Industry standard VME power can be replaced with alternative units using any input power Easy to Read Power Supply Status Lights Removable/Replaceable Euro Card GPS receiver Space for additional 4HP Euro Card (Optional) Fully Functional Computer uses Ampro LB700 EBX processor with Sealevel PC-104 8 port communications Robust I/O connection availability.
(6) External (6) internal RS-232/RS-422 Serial Communication Ports, (4) USB A1.1 Compliant Ports, (2) RJ-45 10/100 Network Ports Accuracy Pitch/Roll 0.003 deg, Heading 0.004 deg (real-time) Position < 20 cm (real-time) All navigation data at 200 Hz Event timer allows for precise coupling with optical and multi-spectral sensors GPS, GPS Antenna, IMU and Integration Computer System (ICS) Hardware/software for precision roll, pitch, heading and navigation Complete inertial navigation solution at IMU data rate (e.g.
Source notes for this comparison
The launch pad preflight calibration is started no earlier ithan 15 hours prior to launch.
The calibrated parameters are valid for 17 hours, thus providing at least two hours of on-orbit use before degradation.
The IMUs will remain in the operate mode from the beginning of this calibration through launch.
Compensation Criteria (C-Crit) The compensation criteria provides a basis for accepting or rejec- ting the results for an IMU calibration.
It is used at the Kennedy Space Center to evaluate unit health.
For example, the compensation criteria for the KT-70 IMU is 0.035 degrees per hour of drift while for the HAINS it is 0.006 degrees per hour.
305 Platform Positioning The IMU gimbals are reoriented and then fixed (or caged) in place.
The IMU-caged orientation is defined as the point at which all resolver outputs are zero.
ch IMU or 7 min between two IMU's if no compensation is applied.
Approximately 85% of this error must be removed via calibration in order to achieve the azimuth alignment specification.
0 Gyro calibration errors are dominated by turn-off turn-on instabilities.
0 Accelerometer calibration errors are dominated by attitude sensitive scale factor errors, second-order accelerometer nonlinearity, and turn-off turn-on insta- bility.
How to treat the numbers below
The preserved notes below keep identity; the table keeps the figures honest. Both have to match the source.
Nothing on this page is a quote sheet. It does not publish catalog prices or a SKU dump.
Spec-sheet comparison of bias stability language in public reports. Verify every figure against the original report before a drawing release.
The library hits for this heading were: Testing of the high accuracy inertial navigation system in the Shuttle Avionics Integration Lab; Space shuttle navigation analysis. Volume 2: Baseline system navigation; Orion Exploration Flight Test-l (EFT -1) Absolute Navigation Design; GPS SPS Performance Standard 2020; Absolute Navigation Performance of the Orion Exploration Fight Test 1; Integrated INS/GPS Navigation from a Popular Perspective.
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Numbers the documents actually state
Rows below follow documents opened for “imu bias stability spec comparison”. If a cell disagrees with the PDF, keep the PDF.
| Document | Stated figure | Source |
|---|---|---|
| Testing of the high accuracy inertial navigation system in the Shuttle Avionics Integration Lab | The launch pad preflight calibration is started no earlier ithan 15 hours prior to launch. | 19920004869 |
| Space shuttle navigation analysis. Volume 2: Baseline system navigation | Approximately 85% of this error must be removed via calibration in order to achieve the azimuth alignment specification. | 19800022935 |
| Orion Exploration Flight Test-l (EFT -1) Absolute Navigation Design | 7 Figure 4: End-to-End Performance Prelaunch This is the phase prior to launch when the vehicle is on the pad. | 20140011752 |
| GPS SPS Performance Standard 2020 | AOD in Normal Operation 14.5 Day AOD Space Clock Stability Group Delay Stability Diff'l Group Delay Stability Satellite Acceleration Uncertainty Other Space Segment Errors 0. | performance-standards-specifications |
| Absolute Navigation Performance of the Orion Exploration Fight Test 1 | We can partition A(tk) as follows A(tk) = Axx(tk) Axφ(tk) AxB(tk) 0 A φφ(tk) AφB(tk) 0 0 A BB(tk) (20) Since the elements ofB are modeled as independent first-order Gauss-Markov processes, ABB(tk) is diago- nal. | 20160001440 |
| Integrated INS/GPS Navigation from a Popular Perspective | The dominant error sources in the INS are shown in Table 1. | 20020041935 |
| Attitude Sensor and Gyro Calibration for Messenger | 8 9 of 15 0 2 4x 0 2 4 Attitude std dev (arcsec) y 0 50 100 150 200 250 0 2 4z Time (minutes) 0 50 100 150 200 250 −0. | 20080012730 |