reliable proximity sensor for use in area with multiple obstructions

[cosmiccloth99]

I am trying to figure out out a reliable solution to the following problem. There is an area that is roughly 60x40 yards in which five pieces of heavy equipment operate. Four are haul trucks that are constantly bringing new material to the site and the other is a wheel loader that traverses the entire location stacking and transporting the material to be processed. So at any given time, there may be one of the four haul trucks and the loader in the area. The site is free of vegetation but the stacked material obstructs the loader operators view and at certain times of the day the sun prevents being able to see behind you while backing up. I would like to implement a system that would trigger a warning light in the cab of the loader anytime one of the haul trucks is behind the loader or  30 to 40 feet in any given direction. So far I the options I have explored aren't well suited to this due to the obstructions and constantly changing landscape. 
 

[sadman]

check out parallax web page they have sensor from sharp based on IR refractive principle you can find a app note on same site how to increase range

hxxps://www.parallax.com/catalog/sensors/proximitymotion

or try out new topology x-band

hxxps://www.parallax.com/product/32213

 
sadman

[j0k3r]

I think that you can be served with an Optical Flow Sensor.

for example:
hxxp://www.aliexpress.com/item/Optical-Flow-Sensor-APM2-5-improve-position-hold-accuracy-Multicopter-ADNS-3080/1893591002.html

or

hxxps://www.aliexpress.com/item/JMT-PX4FLOW-V1-3-1-Optical-Flow-Sensor-Smart-Camera-with-MB1043-Ultrasonic-Module-Sonar-for/32766580894.html

[Parmin]

Long shot here, perhaps use the RCWL-0516 radar module?

[bobcat1]

Hi
You should use a radar module with FM capability who will allow you to measure distance to object
There are many module available on the market ,
This type of module is a bit expansive due to FM capability and cost is in the range of 35~50 USD
Whether you plan to buy one unit ,you can order it from elektor site

All the best

Bobi

[bigtoy]

What about simply installing a backup camera (with display obviously) in the loader's cab? Then the operator can easily see what's going on behind him.

[Checksum8]

Maybe "Ultra-high frequency (UHF) RFID" not sure if it is practical? Range up 12m.

https://www.tersosolutions.com/news/understanding-the-differences-between-uhf-and-hf-rfid-technology/

[CocaCola]

Why not use the obvious?

Create GPS enabled devices with wireless communication between the vehicles or with a central hub that spits out proximity or collision warnings?