The Growing Value of IMUs in Satellite Attitude Control for Space Applications
IMU Requirements in Typical Satellite Applications and the Rationale
In satellite attitude control, feedback control is used to detect deviations from the target attitude and continuously correct them using reaction wheels and other actuators.
An IMU is one of the primary sensors used to maintain stable and highly accurate satellite attitude. By measuring satellite rotation (angular velocity) at a high data rate, it provides fundamental data for state estimation.
Requirements for Inertial Sensors Used in Satellites
- Low noise: To minimize satellite attitude error
- High bias stability: To suppress satellite attitude error
- Compact and lightweight: Contributes to satellite mass reduction and lower launch costs
- Low power consumption: To reduce power usage in increasingly multifunctional satellites where power is constrained
- Radiation tolerance: Required to prevent failures and malfunctions in the radiation-rich space environment
Features of Epson IMUs
1. High Performance, Compact, and Lightweight
Small satellites require high attitude stability within very limited space and mass constraints.
Epson IMUs combine compact size and low weight with low Angle Random Walk (ARW)—a key metric for attitude estimation—thus contributing to higher overall satellite system performance.
- Low noise: Angle Random Walk (ARW) of 0.03°/√h
- High bias stability: Initial bias error of 360 dph (gyroscope), 2 mG (accelerometer)
- Compact and lightweight: 24 × 24 × 10 mm3, 10g
2. TID Tolerance Verified up to 20 krad (M‑G370PDT0 Model)
Expected Trends and Reference Levels of Radiation TID Tolerance by Mission*1
The chart above illustrates typical guideline levels for Total Ionizing Dose (TID) tolerance requirements for IMUs used in space applications, categorized by satellite type and mission profile.
As satellite mission duration increases and orbits move further from Earth’s magnetic field protection into harsher environments or deep space, cumulative radiation exposure increases, requiring higher TID tolerance.
Radiation TID Test Results of Epson IMUs
| Total Dose [rad] | 5k | 10k | 20k |
|---|---|---|---|
| Powered On (3 pcs) | Pass | Pass | Pass |
| Unpowered (1 pc) | Pass | Pass | Pass |
In this TID evaluation, the IMU (M‑G370PDT0) was exposed to radiation in incremental total doses, with functionality and sensor characteristics assessed at each level.
As a result, no functional failures or significant power consumption changes were observed in either powered or unpowered conditions up to 20 krad, confirming that this IMU can maintain functionality in TID environments up to the 20 krad level.
For details, please refer to the following document:
Impact of Total Ionizing Dose Effects on the G370PDT0 (PDF, 4.5MB)
*1 Based on Epson internal research
The TID levels presented on this site are reference guidelines organized based on commonly used space environment models and evaluation methodologies, under multiple assumptions. These reference values do not guarantee performance for specific missions or operational lifetimes, and the actual required tolerance may vary significantly depending on shielding design, solar activity, orbital conditions, and other factors.
[Terminology]
ARW: Angle Random Walk
TID: Total Ionizing Dose
COTS: Commercial Off-the-Shelf
LEO: Low Earth Orbit
GEO: Geostationary Earth Orbit
The unit “rad” used for TID represents absorbed radiation dose and indicates the amount of energy absorbed per unit mass of material. In the International System of Units (SI), absorbed dose is expressed in gray (Gy), and the relationship is as follows:
1 rad = 0.01 J/kg = 0.01 Gy
The TID values shown are converted to absorbed dose in silicon (Si).
*Common Notes
- These products are not designed specifically for space applications. The TID test results are reference data intended to assess radiation tolerance capability and do not guarantee performance in space environments.
- IMUs from the same production lot were used in the TID testing; however, individual internal components are not lot-controlled. Please consider possible component variation in your evaluation.
- All TID test results in this report are expressed in rad units. (1 rad = 0.01 Gy)
- All TID values in this report are converted to radiation absorbed dose in silicon.
Implementation Example
Epson IMUs Adopted by JAXA for the Int-Ball2 Camera Robot Inside the ISS
The autonomous free-flying internal camera robot "Int-Ball2," currently operating in the Japanese Experiment Module "Kibo" aboard the International Space Station (ISS), moves autonomously inside the station in place of astronauts and captures photos and videos remotely from the ground.
In a microgravity environment, precise attitude detection is essential because both three-dimensional translation (X/Y/Z) and rotational motion (roll/pitch/yaw) must be controlled simultaneously.
Epson's M‑G370 Series IMUs were selected for Int-Ball2 due to their high accuracy combined with compact size, light weight, and low power consumption.
Three Key Points of Epson IMUs Supporting Int-Ball2 Attitude Control
- Low-noise performance: Quartz-based sensor technology provides the low noise performance essential for attitude control, contributing to stable autonomous flight in microgravity.
- Compact and lightweight: The 24 mm × 24 mm, 10 g compact design supports space efficiency inside the Int-Ball2 enclosure.
- Low power consumption: Contributes to reduced power usage required for long-duration operation.
For more information, please refer to the following press release:
Epson IMUs Adopted and Operating in JAXA’s Autonomous Internal Camera Robot "Int-Ball2" in the ISS Kibo Module
Recommended product
We introduce products recommended for use in satellite and space equipment applications.
For more detailed information, please feel free to contact us.
| ITAR FREE |
Product Name |
Product type | Brief Sheet | Size [mm] |
Weight [g] |
Gyro Sensor | Accelerometer | Misalignment [°] |
Interface | Operating Temp [℃] |
Power Consumption [mA] |
Power Supply [V] |
|||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Range [°/s] |
BIS [°/h] |
ARW [°/√h] |
Range [G] |
BIS [µG] |
|||||||||||
| ✔ | M-G370PDT | Premium |  |
 24×24×10 |
10 | ±200 | 0.8 | 0.03 | ±8,16*1 | 24 | 0.01 | SPI/UART | -40 to +85 | 16@3.3V | 3.3 |
| ✔ | M-G570PR2 | High end | |
 65×65×30 |
150 | ±475 | 0.5 | 0.04 | ±15 | 14 | 0.15 | RS422 | -30 to +70 | 80@12V | 9 to 24 |
*1 Switchable by configuration on the same model.
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