I'm trying to implement a small-scale localization. My goal is to track a toy vehicle on a Tracking Panel that I will design.

I'm going to make an application which receives distance measurements from the toy vehicle to each sensor. There wil be three sensors in order to implement the trilateration technique.

Each sensor is going to be analog and each sensor is going to have a different frequency predefined in the system. The toy vehicle is going to transmit three of these signals and sensors will be filtering the signal. If a sensor detects its paired frequency, it will reflect the signal back to the vehicle immediately, and the vehicle is going to be measuring the time passed during this operation.

Simple diagram for a sensor

The project is going to have a maximum of 10 square meters range.

Is this approach suitable for my small project?

  • 3
    \$\begingroup\$ What is your requirement for distance accuracy? What time resolution do you expect your time measurement system to have. What timing jitter do you expect your sensor stations to have? How much do you expect the latency of the sensor filters to vary with temperature / time / supply voltage / between each other? What's the speed of light? We can't answer without those details. Once you've spelled them all out, you might have answered most of your questions yourself, and maybe homed in on one significant question. \$\endgroup\$
    – Neil_UK
    Apr 6 at 15:05
  • \$\begingroup\$ If you use ultrasonic signals as vehicle output signal this sounds practical. \$\endgroup\$
    – Jens
    Apr 6 at 15:16
  • 1
    \$\begingroup\$ Do I see "antenna reflects" in the signal-flow diagram? Have you considered how a sensor can receive a signal, while a similar signal transmits (or reflects) at the same time?. The transmitted signal can overwhelm the sensor that is trying to receive. Do you have a method to prevent this interference? \$\endgroup\$
    – glen_geek
    Apr 6 at 17:47

2 Answers 2


You're on the right track in planning to localize the toy by measuring its distance from 3 fixed points, but your technique for those distance measurements is not sufficiently worked out.

Since you mention antennas in your picture, I assume you're planning to use radio waves. The problem is that the time it takes for those waves to travel from the toy to the fixed sensors a few meters away will be measured in nanoseconds. Your circuits would have to create pulses, filter and detect them, and retransmit them in fractions of a nanosecond -- not a project for a beginner. There are ready-made modules for measuring distances this way (search for ultra wideband ranging modules) but they are not for beginners.

Instead, consider using slower moving waves -- sound, or ultrasound -- which take a handful of milliseconds to travel to the fixed sensors. To continue simplifying, think about whether you really need multiple frequencies and two-way transmissions. Could you connect the fixed sensors together with a cable and just compare times of arrival from a single pulse from the toy?


You can use the same system as VOR (VHF omnidirectional range) ... in the "optical" sense.

You need three fixed substations to make the different "angles" that can guide your "toy" object.
Just solve the three received informations (angles).


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