Inertial navigation for defense UAVs

Our solutions are well-suited for integration with various types of defense UAVs, offering versatility and adaptability for different operational needs. Our motion and navigation sensors bring tactical sensing to your systems without compromise on SWaP-C! They are particularly suited to use by integrators.

For UAVs that rely on GNSS, our dual-antenna GNSS receivers offer exceptional accuracy. This is beneficial for surface navigation and aids in transitioning between aerial and ground navigation. Additionally, all sensors support various communication protocols such as RS-232, CAN, and Ethernet, allowing seamless integration with UAV systems.

Finally, it is possible to integrate external positioning solutions such as DVL, or other navigation aids to provide accurate roll, pitch, heading, and altitude data. This enhances navigation in environments where GNSS signals might be weak or unavailable.

At SBG Systems, ensuring the highest quality standards for our inertial measurement units (IMUs) involves a meticulous process. We begin with the optimal selection of high-end MEMS components, focusing on reliable accelerometers and gyroscopes that meet our stringent quality requirements. Our IMUs are housed in robust casings designed to withstand vibrations and environmental conditions, guaranteeing durability and performance.

Our automated calibration process involves a 2-axis table and addresses temperature ranges from -40°C to 85°C. This calibration compensates for various factors including biases, cross-axis effects, misalignment, scale factors, and non-linearities in accelerometers and gyroscopes, ensuring consistent performance in all weather conditions.

Our qualification process further involves strict in-house screening to ensure that only sensors meeting our specifications continue through production. Each IMU is accompanied by a detailed calibration report and is guaranteed for two years. This rigorous approach ensures high quality, reliability, and consistent performance over time, delivering superior IMUs for defense and other critical applications.

We also conducts thorough environmental and endurance testing to ensure reliability. Some of our sensors meet several MIL-STD standards, guaranteeing resistance to shock, vibration, and extreme conditions.

Controlling output delays in UAV operations is essential for ensuring responsive performance, precise navigation, and effective communication, especially in defense or mission-critical applications.

The output latency is an important aspect in real time control applications, where a higher output latency could degrade control loops performance. Our INS embedded software has been designed to minimize output latency: once sensor data are sampled, the Extended Kalman Filter (EKF) performs small and constant-time computations before the outputs are generated. Typically the observed output delay is less than one millisecond.

The processing latency should be added to the data transmission latency if you want to get total delay. This transmission latency vary from one interface to another. For instance, a 50 bytes message sent on a UART interface at 115200 bps will take 4ms for complete transmission. Consider higher baudrates to minimize output latency.

PNT stands for Positioning, Navigation, and Timing — the three foundational pillars that enable any modern navigation or coordination system, whether in aerospace, defense, maritime, autonomous vehicles, or critical infrastructure.

Here’s a clear breakdown:

1. Positioning

This answers the question: “Where am I?”
It provides precise geographic coordinates (latitude, longitude, altitude). Typically derived from GNSS (GPS, Galileo, GLONASS, BeiDou) or INS when GNSS is unavailable.

Essential for tracking, guidance, mapping, and situational awareness.

2. Navigation

This answers: “How do I move from A to B?”
It involves determining direction, speed, and trajectory to reach a destination safely and efficiently. Includes velocity, course, and attitude (roll, pitch, yaw).

Often achieved using IMUs/INS, sensor fusion algorithms, odometry, or GNSS-based navigation.

3. Timing

This answers: “What time is it, precisely?”
Accurate, synchronized time is critical for the coordination of systems and signals. High-precision timing underpins communication networks, military systems, power grids, and GNSS itself.

Even microsecond-level errors can cause failures in comms, data links, or geolocation.

Why PNT Matters ?

PNT is at the core of every modern autonomous or guided system—whether missiles, UAVs, vehicles, USVs, AUVs, or even cellphone networks. When GNSS is degraded or denied, inertial systems (IMU/INS) become the backbone of resilient PNT.

Inertial Measurement Units (IMUs) are sophisticated devices that measure and report a body’s specific force, angular velocity, and sometimes magnetic field orientation. IMUs are crucial components in various applications, including navigation, robotics, and motion tracking. Here’s a closer look at their key features and functions:

• Accelerometers: Measure linear acceleration along one or more axes. They provide data about how quickly an object is speeding up or slowing down and can detect changes in motion or position.
• Gyroscopes: Measure angular velocity, or the rate of rotation around a specific axis. Gyroscopes help determine orientation changes, enabling devices to maintain their position relative to a reference frame.
• Magnetometers (optional): Some IMUs include magnetometers, which measure the strength and direction of magnetic fields. This data can help determine the device’s orientation relative to the Earth’s magnetic field, enhancing navigational accuracy.

IMUs provide continuous data on an object’s motion, allowing for real-time tracking of its position and orientation. This information is critical for applications like drones, vehicles, and robotics.

In applications such as camera gimbals or UAVs, IMUs help stabilize movements by compensating for unwanted motions or vibrations, resulting in smoother operations.

Dead reckoning in aviation is a traditional navigation method that estimates an aircraft’s current position by projecting its last known location forward using measured or assumed parameters such as heading, airspeed, time, and environmental factors like wind.

Instead of relying on external references—such as radio beacons, GNSS satellites, or visual landmarks—dead reckoning uses the aircraft’s own motion information to compute where it should be now relative to where it started. The pilot or onboard navigation system begins with a known fix, then applies the aircraft’s true heading and true airspeed over a given time interval to calculate a new estimated position.

However, because the aircraft is moving through an air mass affected by wind, the computation must incorporate wind direction and velocity; otherwise, the calculated track will deviate from the actual path flown.

In modern aviation, inertial navigation systems enhance dead reckoning by using accelerometers and gyroscopes to measure linear accelerations and rotation rates, continuously integrating these measurements to estimate velocity, attitude, and position. While this inertial dead reckoning dramatically improves independence from external signals, it still accumulates errors over time due to sensor biases and noise. For this reason, INS-based dead reckoning is often paired with GNSS or other aiding sources to bound drift and maintain long-term accuracy.

Despite these limitations, dead reckoning remains essential for ensuring continuity of navigation during GNSS outages, radio-silence missions, or operations in environments where external references are unreliable or denied.