Winning LiDAR Business with Tabor Arbitrary Waveform Generators
Background and customer talking points
A LiDAR system consists of three main systems – the optical, electrical and processing system. A laser forms the basis for the transmitter. In some systems the laser scans the environment mechanically, by essentially moving the laser from left to right and emitting pulses of light. As with a regular radar the receiver detects the light reflected off the target, coverts it to electrical energy using a photodetector and the time delay between transmits and receive is the distance and any shift in frequency (doppler) is the velocity of the target. As light is much higher frequency than Radar the resolution of LiDAR is much better, so it is better at distinguishing between targets (10cm vs 2m at long distances 200M), giving a much more realistic representation of the environment. However, LiDAR tends to be more expensive.
Resolution Detail (optional read)
Typically, a laser at wavelength 905nm will pulse on for tens of ns duration and would transmit 10,000 to 150,000 times a second (10-150kHz pulse rate). Example 20ns pulse width, at a 10kHz pulse rate. The photodetector electrically translates the time and shape of the received pulse. The shape of the pulse, usually in the form of a gaussian shape, will represent the characteristics of the laser beam diffraction and target characteristics.
Important
Jitter plays a larger role in LiDAR that Radar. For example, if the AWG introduces 100ps jitter this will equate to 1.5cm depth uncertainty, or 300ps adds almost 5cm of range uncertainty.
Solution
P2582M - 2.5GS/s Proteus is an ideal candidate for LiDAR testing, especial for multi-target test and AI Algorithm training.
Proteus has multiple channels in a small form factor: To accurately represent for example a 10ns pulse, sample rates in excess of 500MHz are required. A 4 channel Proteus P2584M for example could emulate four independent high-resolution targets pulses to test the AI algorithm.
Proetus has industry leading Jitter specifications. If an AWG is not synchronized to the clock of the LiDAR system (Asynchronous operation), then an AWG such as the Tektronix 5200 can add 440ps of jitter, as opposed to the low jitter option of the P2582/4M which is 200ps. Best operation is when the instrument and the LiDAR are synchronized (Synchronous) – and the jitter will be much less than 1ps providing millimeter resolution.
Establishing the need;
- What types of LiDAR do they make – 905nm/1550nm, mechanical scan, FMCW, coherent.
- How do they emulate different targets today? And how do they do it? Are there any shortfalls?
- Do they test for targets optically or electrically – the AWG would be used if they are test after the photodetector, i.e. electrically.
- How many independent targets do they want to emulate? – some of our LiDAR customers are requiring 16 channels.
- What is there jitter spec?
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