Why Your GNSS Signal Fails And How CRPA Anti-Jamming Antennas Provide The Solution

If your UAV, autonomous robot or vehicle sometimes “loses itself” on the map, you are not alone. Many engineers discover that even with a high-quality GNSS receiver, their system still experiences signal loss, large jumps in position, or long reacquisition times. The root cause is often not the receiver itself, but what happens before the signal reaches it.

In this article, we look at the most common reasons why GNSS fails in real projects – and how CRPA anti-jamming antennas can help you regain control.

Why ordinary GNSS antennas struggle in modern environments

Conventional GNSS antennas are usually single-element designs. They treat the sky as a single “listening point”, amplifying everything that arrives at that point. This creates several issues in today’s environments:

1. They cannot distinguish direction

• Satellite signals and interference arriving from different directions are mixed together.

• A strong local interferer can easily overwhelm weak satellite signals.

2. They have no spatial filtering capability

• Filtering is mainly done in frequency, not in space.

• This is insufficient against nearby jammers or narrowband/broadband interference at or near GNSS frequencies.

As a result, when a UAV flies near a communication tower, a vehicle passes by a local jammer, or a robot operates in a noisy industrial site, the GNSS front-end can saturate, leading to degraded or lost positioning.

Typical interference scenarios in civil applications

From our experience with civil and industrial customers, GNSS failures often appear in the following situations:

• UAVs flying near buildings, base stations or Wi-Fi-dense areas

• Service robots and AGVs operating close to industrial RF equipment

• Connected vehicles sharing roads with drivers using low-cost jamming devices

• Infrastructure nodes located in areas with overlapping communication systems

In many cases, integrators initially suspect firmware or mapping errors, but measurements often reveal that the signal-to-interference ratio at the antenna port is simply too low for the receiver to work reliably.

How CRPA adds the missing “spatial dimension”

CRPA (Controlled Reception Pattern Antenna) adds a crucial capability that ordinary antennas lack: spatial selectivity. Instead of one element, a CRPA array uses multiple elements and combines their signals intelligently. Through this, the system can:

• Steer reception beams toward GNSS satellites

• Form deep nulls toward interference sources

• Dynamically adapt to changing interference directions

Our current CRPA solutions, for example, can support 4, 8 or 16 elements, with the number of simultaneously suppressed jamming directions typically being “number of elements − 1”. A 4-element array can suppress up to 3 directions, while a 16-element array can handle up to 15 directions, within its design range.

Combined with robust hardware design (burnout protection ≥10 W at the RF input, IP65+ mechanical protection, −40 °C to +65/70 °C operation, etc.), this enables GNSS receivers to stay usable in conditions where they would otherwise fail.

From “why did we lose GNSS?” to “we passed the test”

For many civil projects, adopting a CRPA anti-jamming antenna changes the conversation from reactive troubleshooting to proactive robustness:

• UAV flight tests no longer need to avoid certain areas just because “GNSS is bad there”

• Autonomous vehicles can maintain position integrity more consistently along their routes

• Industrial robots and infrastructure nodes become less sensitive to surrounding RF equipment

In addition, our integrated anti-jamming units can include a built-in GNSS receiver that outputs PVT data (position, velocity, time) directly, which simplifies integration for teams that prefer a more turnkey approach.

A practical next step

If you are currently dealing with GNSS reliability issues, a good next step is to:

1. Confirm whether your current antenna is a simple single-element design.

2. Measure or estimate the interference environment your system faces.

3. Evaluate whether a 4-, 8- or 16-element CRPA antenna is appropriate for your SWaP and performance needs.

Our team has summarized common technical questions – from supported bands and power consumption to anti-spoofing and interface options – in a dedicated Anti-Jamming Antenna Q&A document, and we also provide clear price/specification sheets to help you compare models quickly.

If you would like to discuss your specific UAV, vehicle, robotic or infrastructure application, feel free to contact us. We are happy to share integration experiences, including examples with popular civil flight controllers and navigation protocols.