How do road features like jersey barriers, grassy medians, walls, gantries, and tunnels impact the performance of a side-firing radar?

[Sergei Sharonov]

#3151

The propagation physics of microwave signals remains consistent for any radar. The road structures mentioned can cause reflections and multipath propagation of radar signals, leading to false targets. Here’s how the Speedlane Pro radar addresses these challenges:

1. High-definition range resolution: Speedlane Pro offers enhanced range resolution, differentiating between genuine and false targets. Older radars suffered from limited range resolution due to the restricted bandwidth of their transmitted signals. Speedlane Pro operates at the maximum bandwidth permitted by the FCC and CE.
2. Dynamic clutter map: The radar maintains a dynamic map of stationary targets. This map assists in distinguishing between clutter and real targets.
3. Proprietary tracking algorithm: Speedlane Pro deploys a unique algorithm that identifies specific signal patterns, thereby suppressing ghost targets.
4. User hints: For even greater accuracy, Speedlane Pro can incorporate user input regarding lane geometry and traffic direction.

Let’s delve into the specific effects of different road structures:

1. Jersey barriers: These present two challenges: occlusion and multipath propagation. Occlusion is a concern if the radar’s view is blocked, but as long as it can detect at least the top half of a vehicle, it should operate correctly. Multipath propagation can create ghost targets, but our tracking algorithm generally filters them out.
2. Grassy median: Speedlane Pro adjusts its internal parameters for grassy medians. After approximately 100 vehicles pass in the adjacent lane, the radar’s internal calibration should complete, optimizing its performance.
3. Walls: Walls can have varied impacts based on their location relative to the radar. A wall at the far edge of the last lane may create distant ghost targets that are always filtered out. It also creates a very strong direct return signal and for the best performance, we recommend to have a few feet of curb between the lane and the wall.
   However, a wall behind the radar is more problematic. It could lead to ghost targets within the actual lanes. Most of these are filtered by our tracking algorithm, but for optimal performance, it’s best not to mount Speedlane Pro directly on or near a wall.
4. Gantries and tunnels: These structures often produce a high number of false targets, compromising radar performance. We advise against installing Speedlane Pro under gantries or inside tunnels.

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