GNSS protection & IMU backup positioning system
Navigating unmanned aerial vehicles (UAVs), or drones, requires precise and reliable positioning information. Global Navigation Satellite Systems (GNSS), such as GPS, are commonly used for drone navigation, but they can be susceptible to interference or disruption from a variety of sources. To mitigate these risks, drone engineers can implement GNSS protection and backup positioning systems to ensure that drones can continue to navigate safely and accurately even in challenging environments.
In this article, we’ll explore the various GNSS protection strategies that can be implemented, including antenna protection and electromagnetic interference (EMI) shielding. We’ll also look at how backup positioning systems, such as inertial measurement units (IMUs), optical flow sensors, barometric altimeters, and radio navigation systems, can be used to supplement GNSS data in the event of a loss of signal or other disruptions. We’ll examine the technical aspects of these systems, including their accuracy, precision, and compatibility with existing drone hardware and software. Finally, we’ll provide recommendations for selecting and implementing GNSS protection and backup positioning systems for drones, and we’ll highlight some of the latest technologies and products that are available to drone engineers.
As an embedded engineer and GNSS engineer, I can provide you with some guidance on building a GNSS protection system for your drone. The main goal of a GNSS protection system is to ensure that the drone can maintain accurate and reliable navigation, even in challenging environments where GNSS signals may be weak or obstructed. This can help prevent accidents and improve overall flight performance.
Here are some steps to consider when building a GNSS protection system for your drone:
- Choose a GNSS receiver module: You’ll need a high-quality GNSS receiver module to receive satellite signals and calculate the drone’s position, velocity, and orientation. One popular choice is the u-blox NEO-M8N GNSS receiver module, which is designed to provide reliable positioning performance in challenging environments. It can be purchased from the u-blox website or from distributors such as Digi-Key.
- Add a GNSS antenna: To ensure that the GNSS receiver module can receive signals effectively, you’ll need a good-quality GNSS antenna. There are many different types of GNSS antennas available, but some popular choices for drones include patch antennas and helix antennas. A recommended option is the Taoglas GPS.05 antenna which can be purchased from Digi-Key.
- Incorporate a GNSS signal filter: In some cases, external factors such as RF interference or multipath can disrupt GNSS signals and cause navigation errors. To mitigate this, you can add a GNSS signal filter to the system. One option is the Tallysman TW2643POC GNSS filter, which can be purchased from Mouser.
- Add a backup positioning system: In case of GNSS signal loss or interference, it’s a good idea to have a backup positioning system to rely on. One option is to add an inertial measurement unit (IMU) to the drone, which can provide accurate orientation and velocity data even without GNSS signals. A recommended option is the MPU-9250 IMU from TDK InvenSense, which can be purchased from Digi-Key.
- Test and calibrate the system: Once you’ve assembled the GNSS protection system, it’s important to thoroughly test and calibrate it to ensure that it provides accurate and reliable navigation data. You can use software tools such as RTKLIB or Piksi Multi to evaluate the performance of the GNSS receiver module and make any necessary adjustments.
If you require maximum accuracy and precision for your drone GNSS protection system, I would recommend using the u-blox F9P GNSS receiver module. The u-blox F9P is a high-performance GNSS receiver module that supports multiple GNSS constellations and signal frequencies. It uses advanced positioning algorithms and signal processing techniques to provide highly accurate and precise position, velocity, and timing information. The F9P also includes built-in support for real-time kinematic (RTK) and precise point positioning (PPP), which can further improve accuracy and precision.
In addition to the F9P module, you would also need a high-quality GNSS antenna that is compatible with the frequencies and constellations used by the F9P. The Taoglas GPS.05 antenna that I recommended earlier would be a good choice for use with the F9P. You may also want to consider using a multi-frequency GNSS signal filter, such as the Tallysman TW3740 filter, to reduce interference and improve signal quality. This filter is compatible with the frequencies used by the F9P and can provide additional protection against signal distortion.
Finally, it’s important to note that achieving maximum accuracy and precision with a GNSS system requires careful calibration and tuning of the system. You may need to perform additional testing and tuning to optimize the performance of your drone’s GNSS protection system, based on the specific requirements of your project. To purchase the u-blox F9P GNSS receiver module, Taoglas GPS.05 antenna, and Tallysman TW3740 filter, you can visit distributors such as Digi-Key or Mouser, or purchase directly from the manufacturers’ websites.
Protect GNSS from damage or interference
To protect your GNSS antenna from damage or interference, you can consider using an antenna protector or shield. Antenna protectors can help to prevent damage from impacts, such as from a crash or collision, and can also help to reduce interference from other electronic devices or signals.
One type of antenna protector that you might consider is a radome. A radome is a protective enclosure that is placed over the GNSS antenna. It can help to protect the antenna from damage, as well as from environmental factors such as moisture, dust, and debris.
Radomes are available in various sizes and materials, including fiberglass and plastic. Another type of antenna protector that you might consider is an electromagnetic interference (EMI) shield. EMI shields can help to reduce interference from other electronic devices or signals, which can help to improve GNSS signal quality and accuracy. EMI shields are typically made of metal and are designed to fit over the GNSS antenna.
To purchase antenna protectors or shields, you can visit online electronics retailers such as Digi-Key, Mouser, or Arrow Electronics. These retailers carry a wide selection of electronic components, including GNSS antennas and accessories. You can also visit the websites of GNSS antenna manufacturers such as Taoglas or Tallysman, which offer a range of GNSS antennas and related products.
When choosing an antenna protector or shield, be sure to select one that is compatible with your specific GNSS antenna and application. Some GNSS antennas may come with built-in protection features, such as a radome or EMI shield, so be sure to check the specifications of your antenna before purchasing additional protection equipment.
Backup positioning system
And of course, having a backup positioning system is a great idea to ensure that your drone has reliable navigation even in the event of a failure or interference with the primary GNSS system. There are several backup positioning systems that you can consider for your drone, including:
- Inertial Measurement Unit (IMU): An IMU is a device that measures and reports a drone’s velocity, orientation, and gravitational forces. It can be used to provide backup navigation information if GNSS signals are lost or disrupted. IMUs are available from various manufacturers, including Bosch Sensortec and STMicroelectronics. You can purchase IMUs from online electronics retailers such as Digi-Key, Mouser, or Arrow Electronics.
- Optical Flow Sensor: An optical flow sensor is a device that uses a camera to measure the movement of the ground beneath a drone. It can be used to provide backup navigation information in environments where GNSS signals may be obstructed or unavailable, such as indoors or in urban canyons. Optical flow sensors are available from manufacturers such as Pixhawk and Holybro. You can purchase optical flow sensors from online drone retailers such as GetFPV or ReadyMadeRC.
- Barometric Altimeter: A barometric altimeter is a device that measures air pressure to determine a drone’s altitude. It can be used to provide backup altitude information in the event of a loss of GNSS signals or other positioning systems. Barometric altimeters are available from various manufacturers, including Bosch Sensortec and STMicroelectronics. You can purchase barometric altimeters from online electronics retailers such as Digi-Key, Mouser, or Arrow Electronics.
- Radio Navigation System: A radio navigation system, such as a radio direction finder or a VOR receiver, can be used to provide backup navigation information if GNSS signals are lost or disrupted. These systems rely on radio signals transmitted from ground-based or satellite-based sources. Radio navigation systems are available from various manufacturers, including Garmin and BendixKing. You can purchase radio navigation systems from online aviation electronics retailers such as Aircraft Spruce or Chief Aircraft.
When selecting a backup positioning system, it’s important to consider the specific requirements and constraints of your drone application, as well as the compatibility of the system with your existing hardware and software. You may also need additional testing and tuning to integrate the backup system into your drone’s navigation system.
To purchase backup positioning systems and related components, you can visit online electronics retailers such as Digi-Key, Mouser, or Arrow Electronics, or online drone and aviation electronics retailers such as GetFPV, ReadyMadeRC, Aircraft Spruce, or Chief Aircraft.
In conclusion, GNSS protection and backup positioning systems can greatly enhance the reliability and safety of drone navigation.
By implementing measures such as antenna protection and EMI shielding, drone engineers can reduce the risks of signal loss or interference, while backup positioning systems such as IMUs, optical flow sensors, barometric altimeters, and radio navigation systems can provide additional sources of positioning data to ensure that drones can continue to operate safely and accurately even in challenging environments.
When selecting and implementing GNSS protection and backup positioning systems for drones, it’s important to consider the specific requirements and constraints of your application, as well as the compatibility of the system with your existing hardware and software. You may also need to perform additional testing and tuning to ensure that the backup system integrates seamlessly with your drone’s navigation system. Some of the latest technologies and products that are available for GNSS protection and backup positioning systems include u-blox M8P and F9P receivers, as well as IMUs from Bosch Sensortec and STMicroelectronics, optical flow sensors from Pixhawk and Holybro, barometric altimeters from Bosch Sensortec and STMicroelectronics, and radio navigation systems from Garmin and BendixKing.
In summary, by implementing GNSS protection and backup positioning systems, drone engineers can greatly enhance the reliability, safety, and performance of their UAVs, and ensure that they can operate effectively in a wide range of environments and conditions.
