Posting a conversation with Sven that might be helpful for others as well
I read the topic about the new "Underwater GPS System" from here1 and I also visit you website but I have still some question to you, I don't find an answer for.
I am from the University of Rostock in Germany and we need a small equipment from getting the position of our underwater vehicles for control purposes.
Here my questions:
How precise is the system? I read that you post 1 % of the distance from locator to receiver but you also wrote that it depends on many different aspects. So what are this aspects and how are you empirical values for using this system in the field and in the laboratory based on the precision.
I saw that you system consists of four receivers and one locator. Is there a special arrangement of how I need to setup the four receivers? Is it part of the installation process to program where the receivers are and how fare they are away from each other or is there a required arrangement?
You say that the system is really robust against noisy environment, that is go but I ask myself how robust is the system against reflections? To example if I want to use the system in a small swimming pool I think there are a lot of acoustic reflections which can influence the system, have you experience with this kind of environment and how well the system works under such conditions?
Is it possible to use the system also without a gps fix inside buildings (indoor swimming pool)?
How fast is the position update rate of the system?
I think your company is a small start up company, so where the knowledge comes from and how long are you developed and test the system?
It would be really nice if you could answer my question because I should present your system on a meeting on Wednesday.
Hi Sven. Thank your the questions. I will try to answer all of them.
Precision: How you place the receivers will affect the precision. The GUI comes with a "heatmap" tool that estimates the precision depending on how/where you place the references (receivers). This tool will help you with the reference placement. With about 3-4 m reference separation we typically get a precision of 2-3m at 100m. Background noise, like echo sounders and sonars can also affect the precision.
Receiver arrangement: Yes, the receivers have to be placed with a few meter separation to get a good coverage. The position of the receivers (relative to a defined origo) must be written to the system. This is done through the web GUI or the API.
Robustnes: The system works fine in swimming pools. The swimming pool is a worst-case scenario for reflections, but the system does handle this type of environment!
GPS: Yes, you can use the system without GPS fix. You can run on only acoustic position and get relative positions without GPS references
Update rate: The update rate is 4 Hz.
Company: Water Linked is 4 years old, and we have been working on this technology since it's start-up. The engineers have decades of experience from ultrasound and radar applications.
We are working on a video that shows how to configure and use the system, and I will post information on this forum when it is ready.