Last Updated: Sep 19th, 2018 - I will be updating my original post as people correct me and I learn new things.

Well, I am next off to monkey around with LIDAR technology and interestingly there is not one single document available that can explain different LIDAR technologies available for PixHawk "or" Pixhawk compatible devices, what each device does, limitations, programmability etc. 


I will attempt to take a shot at what I have learned so far but I would like the community to chime in so we can have a consolidated document for future reference. Just like a wiki page.

LIDAR = A detection system that works on the principle of radar, but uses light from a laser.

Applications:

1D - Range Finders. Typically work in combination with FC such as PixHawk.
2D - Short Range Obstacle detection.
3D - Used for surveying, mapping and point clouds. A method that measures the distance to a target by illuminating the target with pulsed laser light and measuring the reflected pulses with a sensor. Differences in laser return times and wavelengths can then be used to make digital 3-D representation of the target. 

LIDAR Types: So it appears there are two types of LIDAR sensors as far as the technology goes behind it.

1. traditional LIDAR sensors
2. Time of Flight (ToF) - More to come later...

SETUP:

So what are the components of an overall LIDAR system/solution?

Well, first you need to decide what the LIDAR will do in the real life world. That will determine the type of LIDAR sensor you will need for your fixed wing aircraft or the copter you are planning to use.

Do you really need a flight controller like PixHawk? the answer is NO BUT it depends on the application. If the application is rangefinder or does object avoidance, Pixhawk along with Mission planner can support such application on a drone.


If you are going to use the LIDAR for Mapping or analysis, that's whole new setup but do you really need a flight controller for such LiDAR to work? My understanding is NO, as long as we can provide LIDAR with the position of the aircraft using a separate GPS and IMU for processing data.

LIDAR SENSORS - Bufete :)

I am planning to put a power point presentation at the end which will consolidate all the tips, discussions here for future reference. Thanks for joining the discussion.

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Replies to This Discussion

You've got a wide range of sensors there, which all do different things. They break down into this:

1D: These are just range finders. (1,2,4)

2D: These are useful for short-range obstacle detection (3,5,6, although you missed the best of them, the RP-Lidar A2)

2.5D: These are meant for creating point clouds. (6,7,8)

LIDAR is a good thing.
That's just a question - WHY?

Collision avoidance mode.
This mode is definitely useful. But only if the software works correctly.

Distance measurement.
This mode can be useful. It is easier for the flight controller CPU and its data can help to provide flight.
But everything will depend on the software. Since without the right software, a lidar is just an expensive piece of hardware.

Mapping mode.
To ensure flight safety and navigation - is useless. Since for comparison - it is required that the drone ALREADY had a digital map with which to compare what the lidar sees.
In addition, it is not clear whether the notion of "obstacle" for a drona and for a lidar coincides. The branches of the trees for the belt are exactly a hindrance. And for the lidar?
And more - processing data from the lidar for building a digital image of the terrain - this is what processor will it handle? The flight controller?
Why load with external tasks the processor, on which the safety of flight depends? So - you need to put another processor, which will process data from the lidar. For him, you need to write software. It needs to be mated with a flight controller, etc.
For what?

You might find some more information here.

And yet ...

The very idea of using lidar is good. Only everything will depend on two factors - lidar's resolution (how small objects it can detect and how much it will detect them GUARANTEED) and the possibility of correct pairing with the controller, that is, software.

I really like this discussion. 

-- Eylon 

Thanks, Chris. I will add it to the list.

I am still struggling to understand the correlation between liDAR and FC.

So for options 1,2,3,4,5,6 I can understand the function of the FC, but for 6,7,8 is it safe to assume that LiDAR for mapping works independent of FC and uses its own GPS perhaps or not even needed?

Is there wiring diagram I can look at for LiDAR mapping solutions.

Chris Anderson said:

@Igor - Sorry kind of lost you. Are you asking questions or telling us something you know?

I see liDAR sensor on that website. What exactly are you asking us to read?

Laser Developer said:

You might find some more information here.

Yes, for mapping/scanning the Lidar works independently of the flight controller and often has its own GPS and/or IMU for more accurate recording. 

Lidars only work with the FC in the case of obstacle avoidance or (common in cars, rare with drones) SLAM. 

-c

iSkyMaster said:

Thanks, Chris. I will add it to the list.

I am still struggling to understand the correlation between liDAR and FC.

So for options 1,2,3,4,5,6 I can understand the function of the FC, but for 6,7,8 is it safe to assume that LiDAR for mapping works independent of FC and uses its own GPS perhaps or not even needed?

Is there wiring diagram I can look at for LiDAR mapping solutions.

Chris Anderson said:

I was already interested in this issue for my project. As a means of ensuring flight safety.
And I tried to study the existing literature.

But I do not have practical application.

Based on what I know about the principles of operation of such devices and on the read - I got such an opinion.

On the Internet, a lot of articles about the excellent qualities of these devices. On the great opportunities that their use gives.
But with the practice of application - a lot of questions. And the answers (clear, concrete and understandable) are much less.

Since for me (I think for many others) the practical value of lidars will appear when there are absolutely clear, understandable and unambiguous recommendations - "... for the lidar to work it is necessary to connect the device to the port such and such, the firmware should be such, it is configured so and so ... "

And there will be examples of positive use.

I must say that the situation is changing rapidly. And maybe I missed something. Since this question was dealt with some time ago.

Similar tasks are also being tried using millimeter-wave sensors.
If I'm not mistaken, this is the responsibility of the Electronics Design. Sensors D3 Engineering...

My apologies for being brief. It looks like you are in the process of collecting information. Perhaps these will help:

This product is a scanning LiDAR sensor that integrates with the PixHawk FC for sense-and-avoid.

This product is a laser altimeter that integrates with the PixHawk FC.

This and this might give you an indication of the work that the ArduPilot team and others have done with LiDAR.

iSkyMaster said:

I see liDAR sensor on that website. What exactly are you asking us to read?

Laser Developer said:

You might find some more information here.

@Laser Developer - Great links! I will take my time to read the Scanning LiDAR and Laser Altimeter white papers. Seems very detailed and this is exactly what I was after. Thanks!

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