we have bought the “ESP32 UWB Pro with Display” to see if it can meet our requirements that we have for one of our projects.
We measure the distance between two objects, which can vary from 50 to 200 meters, and the accuracy is not so important and can vary by a few meters. For us it is important that we know that the object is 50, 100 and 150 meters away from the other object.
We used the example code from Makerfabs. We updated the parameters to work for our long range application: Changed the data rate to 110 kB per second, the transmit pulse frequency to 64 Mhz and the preamble to 2048.
We found that after 90 meters we lose the signal, it comes back, but it’s not quite stable. If we continue to go further, then it doesn’t work at all. I read that it is possible to measure 150 meters distance.
What are we doing wrong that we can not achieve this distance?
I can’t say for sure how much effect it would have but as a general rule putting the UWB antenna right next to a USB cable and some circuit components is bad for the range. Placing the antenna like that is also going to give you some significant orientation dependencies in both maximum range and measured distance.
Unfortunately the solution, a better antenna and better board layout, isn’t particularly practical if you want to use that specific hardware. Or most of the other off the shelf solutions for that matter, they are designed for simplicity and compactness rather than all out no compromises RF performance.
In more practical terms playing with orientations and getting things further aboth the ground are probably your best bets for getting more range without changing hardware.
Hi @Josh
this have some relation to the Fresnel zones. Long time ago we have done some measurements in about 1.2m - 1.5m height the signal gets lost at some distance and then comes back after 5-10m for a while. Then we realize the Fresnel zones and increased the height to 2m and since then we don’t observe this issues anymore.
For most of radio signals you should take care only about 1st Fresnel zone, but for UWB it seems that also other zones are important.
Practical example:
Distance between antennas = 100m
Frequency = 6.5GHz
1st zone radius = 1.07m
2st zone radius = 1.52m
3st zone radius = 1.86m
Distance between antennas = 200m
Frequency = 6.5GHz
1st zone radius = 1.52m
2st zone radius = 2.15m
3st zone radius = 2.63m
When the ESP320 UWB was raised a few meters above the ground, the range improved significantly. Also, positioning the antenna in the direction the waves were coming from was very helpful in achieving this distance. Finally, we were able to measure a distance at 150 meters. We will continue the experiment next week to see how far we can get with the current hardware.