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GNSS-Denied Navigation Kit

The GNSS-Denied Navigation Kit is a device specifically designed for GNSS-denied environments, combining the capabilities of our Attitude and Heading Reference System (AHRS), the POLAR-300, with those of our Visual Navigation System, the VNS01. This integration ensures dead reckoning navigation with minimal drift. It represents an advanced solution for precise and stable navigation in challenging scenarios. The kit is equipped with cutting-edge algorithms capable of detecting and countering sophisticated 'jamming' and 'spoofing' techniques. By merging the POLAR-300 and the VNS01, our focus has been on enabling navigation in GNSS-denied environments, surpassing traditional techniques with our latest innovation. The result is highly accurate GNSS-denied navigation, maintaining error rates as low as 1% over covered distances.

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    GNSS-Denied Navigation Kit
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    GNSS-Denied Navigation Kit
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    Kit Navegacion con GNSS denegada
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    GNSS-Denied Navigation Kit
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    GNSS-Denied Navigation Kit
  • GNSS-Denied Navigation Kit
  • GNSS-Denied Navigation Kit
  • Kit Navegacion con GNSS denegada
  • GNSS-Denied Navigation Kit
  • GNSS-Denied Navigation Kit
Visual-Based Techniques for an Accurate & Reliable Navigation System in GNSS-Denied Environments
Visual-Based Techniques for an Accurate & Reliable Navigation System in GNSS-Denied Environments

The GNSS-Denied Navigation Kit employs a variety of sensors, including visual navigation sensors that utilize advanced techniques such as “visual Odometry” (VO) and “template matching.” In combination with onboard sensors, these techniques facilitate highly accurate calculations of the aircraft's absolute position, orientation, and relative ground movement. This integrated approach delivers exceptional navigation and attitude performance, ensuring robust and precise navigation capabilities in GNSS-denied environments.

Proven Against Counter-UAV/Anti-UAV Measures: Jamming & Spoofing Detection and Protection
Proven Against Counter-UAV/Anti-UAV Measures: Jamming & Spoofing Detection and Protection

The GNSS-Denied Navigation Kit integrates a robust internal algorithm that utilizes multiple sensors available in the system to detect the most sophisticated spoofing attack methods, applying measures to prevent deception while maintaining precise navigation.

Precise Attitude and Position Estimation
Precise Attitude and Position Estimation

The POLAR-300 is a highly accurate AHRS, rigorously tested under various conditions and proven through thousands of flight hours. Its demonstrated precision is comparable to FOG IMUs. Thanks to this, the POLAR-300 is capable of performing low drift dead reckoning navigation, even without the assistance of visual sensors.

No Map Loading Required
No Map Loading Required

The system autonomously builds maps by capturing real-time images using its onboard camera when a valid GNSS signal is available. These unique maps are stored in its internal memory for use in case of GNSS signal loss.

Built-in Air Data System (ADS). Key for Dead Reckoning Navigation
Built-in Air Data System (ADS). Key for Dead Reckoning Navigation

The product includes an Air Data System (ADS) that provides temperature, static, and dynamic (pitot) pressure values. These variables are utilized in the estimation process to calculate air density, indicated airspeed, true airspeed, and barometric altitude. The data from the ADS, combined with GNSS data and the onboard camera in the internal algorithms, enhances the system's precision significantly. In cases of navigating in dead reckoning conditions when GNSS signals are unavailable, the ADS ensures low-drift navigation.

Ultra-compact and Easy to Integrate. Excellent for Class I and II UAVs

Compact, lightweight, and integrated for effortless installation on unmanned aerial platforms. Its simple wiring eliminates the need for complex electrical installations, ensuring easy integration into the user's system.

As technology advances and geopolitical challenges arise, the demand for reliable and secure navigation for Unmanned Aerial Systems (UAS) intensifies. Ensuring operational integrity in both civil and defense sectors is paramount. The advent of systems designed to disrupt radio-electronic navigation and communication accentuates this need. With GNSS signals increasingly under threat from both unintentional and intentional interference, the shortcomings of traditional navigation systems are evident.

UAV Navigation-Grupo Oesía offers a robust solution that combines different technologies to address these challenges. Immune to external disruptions, this solution represents the future of autonomous navigation. 

Disruptions to GNSS signals can arise from various sources, including natural phenomena, technical glitches, and, more concerningly, deliberate interference or jamming by adversaries that threaten the integrity of GNSS signals. In this document, we will focus on the latter, which can be categorized into two types of attacks: Jamming, where the GNSS signal is intentionally inhibited, and spoofing, which is even more dangerous, as adversaries simulate a GNSS signal to deceive the aircraft, leading it to crash or redirect to an unintended location.

When faced with such disruptions, the implications can be devastating for operations that depend solely on these signals for navigation. In situations where every second is crucial, such as in time-sensitive military operations or emergency responses, even slight deviations from the planned route or brief navigation interruptions can result in catastrophic outcomes. The escalating occurrences of GNSS signal interruptions emphasize this weakness, creating a pressing need for a more resilient navigation solution.

  1. Jamming: Jamming refers to the deliberate disruption or interference of GNSS signals. This interference overwhelms the genuine GNSS frequencies with noise or other interruptions, making it challenging to receive the original signal and often leading to lost connections or inaccurate data. The dangers of jamming are significant. Systems that rely heavily on GNSS might find themselves without navigation, potentially going off-course, jeopardizing their mission, or exposing assets to risks.
  2. Spoofing: On the other hand, spoofing involves creating and transmitting fake GNSS signals. Rather than merely disrupting the signal as jamming does, spoofing deceives a GNSS receiver into thinking it's receiving a legitimate signal. This deception can produce completely false positioning data, leading users to navigate inaccurately. The risks of spoofing are profound. Sophisticated spoofing attacks can allow adversaries to take over a system or vehicle, potentially redirecting it or causing it to crash.

Overflying known areas

When flying over areas that have been previously covered, the VNS01 has a pre-generated map in its internal memory. In the event of a GNSS signal loss, this pre-existing map enables the system to navigate effectively. In actual tests conducted using advanced spoofing and jamming techniques, the system exhibits virtually no positional error.

Overflying known and unknown areas

Another common scenario involves aircraft taking off without GNSS from previously covered areas, for which maps have already been generated and stored in VNS01 memory. At the same time, these aircraft might also fly to areas they have never flown over, meaning no stored maps would be available. In such situations, based on internal tests, the system is capable of the aircraft maintaining an error of about 1% of the total distance traveled.

Figure 1: VNS01 drift after 6 km of unknown zone

Note: The target icon in the image represents the real system position according to the internal GNSS information. The arrow, barely appreciated under the aircraft icon, indicates the aircraft's estimated position as reported by the VNS01. The aircraft icon shows the position of the aircraft as estimated by the FCC.

As soon as the aircraft enters the known zone, the VNS01 cancels the positional error, as illustrated in the picture below.

Overflying unknown areas

The most challenging scenario for the system involves flights in an entirely unknown area, without any available internal map and without a GNSS signal from start to finish, all while under constant spoofing attacks. With such challenging conditions, the system manages to maintain a positional error of about 1% relative to the total distance traveled.

Figure 2: Drift after one loop in the unknown FP

Loitering at unknown locations

To demonstrate the VNS01’s learning and adaptation capabilities in unfamiliar terrains, a test involving the execution of a loiter maneuver over an unknown area with no GNSS availability is carried out. To maintain a minimal error, despite the absence of maps or GNSS, the VNS01 adapts to the operational conditions and recognizes the area where it has been flying over. Even though it won´t be able to generate high-quality maps, it must ensure its error does not increase over time. In these tests, after flying for an extended period, the accumulated error reaches only 0.5% of the total distance traveled.

Dead Reckoning with POLAR-300

Lastly, the final tests involve flights without the VNS01, relying exclusively on the capability of the POLAR-300 to perform dead reckoning navigation using only its inertial sensors. In these flights without GNSS, the accumulated error is expected to be 10% of the total distance traveled.

Figure 5: Inertial navigation accumulated drift after 6.6 km

Distance covered
Drift (m)
Drift (%)
Known areas (map available)*
4 km
0 m
0 %
Unknown areas (no map available)**
7 km
80 m
1.1 %
Loitering in unknown areas (no map available)
16.7 km
90 m
0.5 %
Flight without VNS01
6.6 km
690 m
10 %

*Known areas are previously overflown regions. Therefore, the VNS01 has a map available..

**Unknown areas are regions that have not been previously flown over. Therefore, the VNS01 lacks an available map.


POLAR-300 Size (mm, H x W x L)
POLAR-300 Weight
22 x 40 x 82 mm
76 g
VNS01 Size (mm, H x W x L)
VNS01 Weight
24 x 80 x 77 mm
100 g
POLAR-300 Connector
Glenair MWDM2L-15PCBR-.080
VNS01 Connector
Binder 86 6319 1120 00008
Static / Pitot Port Diameter
3.0 mm
Up to 90% RH, non-condensing
Temperature Range
-40 ºC to +85 ºC
Shock Survival
500 g.  8 ms.1/2 sine
Input Voltage
9 to 36 V DC
POLAR-300 Power Consumption
1W (@ 12 VDC)
VNS01 Power Consumption
5W (@ 12 VDC)
GNSS Antenna Connector
50 Ohm SMA Female
Airspeed Range
15-220 kt
43-450 kt (Under request) 
Airspeed Accuracy
±3 % reading
Airspeed Precision
± 1 kt
Altimeter Range
-2,000 to +36,000 ft AMSL
Altimeter Accuracy
±3 % reading
Altimeter Precision
± 1 ft
Internal Magnetometer
3 Axes
0.1 μT
Pattern Recognition
No Drift
Visual Odometry
~1% of distance covered
No Visual Sensors
< 30 m/min (continuous)
Roll/Pitch Error
< 0.5º
Heading Error
< 1º
Estimated Position Accuracy (GNSS available)
2.5 m CEP, GNSS & SBAS available
Online Sensor Diagnosis
Sensor Failure Tolerance
All Single
Several multiple
Over 60,462 h
Receiver Type
72 Channel, L1C/A, L1OF, B1I, E1B/C
Time to First Fix (Cold / Hot)
< 26 s / < 2 s
Altitude / Velocity Limit
50,000 m / 500 m/s
Navigation Update Rate
5 Hz
30 ns RMS, 60 ns 
Horizontal Position Accuracy
2.5 m (CEP, 50%, 24 h static, -130 dbm, >6 SVs)
Heading Accuracy
0.4o Dynamic (50% @ 30 m/s)
Dual GNSS Compass / External GNSS
External Payload Available (DGC01)

The kit comprises a VNS01 - Visual Navigation System, a POLAR-300 AHRS, and all the necessary ancillaries for the installation and connection of both systems to Visionair, enabling the reception of positioning and navigation data:

The kit includes the following software components:

  • Visionair Dongle
  • Visionair Analytics software
  • LibUtils libraries. Libutils is included to ease the integration process of the system. Support Service:
    • 10 hours of the Premium Support package 
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UAV Navigation is a privately-owned company that has specialized in the design of flight control solutions for Unmanned Aerial Vehicles (UAVs) since 2004. It is used by a variety of Tier 1 aerospace manufacturers in a wide range of UAV - also known as Remotely Piloted Aircraft Systems (RPAS) or 'drones'. These include high-performance tactical unmanned planes, aerial targets, mini-UAVs and helicopters.