Optimal pseudorandom pulse position modulation ladar waveforms

Fluckiger, David U.; Boland, Brian; Marcus, Eran

doi:10.1364/ao.54.002183

Cited by 6 publications

(6 citation statements)

References 5 publications

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“…From now on, the SNR of the ego signal is meant with k SN = k SN,s=2 . Inserting this into (12), the equation can be solved for the extinction distance or extinction TOF of the ego signal, which is the vanishing second laser signal t TOF,2 = t ext , resulting into…”

Section: A Signal-to-noise Ratiomentioning

confidence: 99%

“…For millions of LiDAR systems, different frequencies for every LiDAR system might be difficult. To get different laser frequencies easily for all LiDAR systems, the laser difference can be imitated by an intentional random time delay of the own pulse repetition frequency, which is also called PPM [12]- [17]. Due to eye safety, the laser can only be delayed so that the pulse repetition frequency is never increased.…”

Section: B Reduction Of Lidar Interferencementioning

confidence: 99%

“…TCSPC LiDAR using single-photon detectors like singlephoton avalanche diodes (SPADs) underlie dead times and are thus often restricted to first-photon measurements. TCSPC systems focus on LiDAR interference approaches like pulseposition modulation (PPM) [12]- [17] or CDMA realized by dual-pulse emission considering dead time [18]. One paper even combines CDMA and PPM applied to scanning LiDAR [19].…”

Section: Introductionmentioning

confidence: 99%

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Probability of Unrecognized LiDAR Interference for TCSPC LiDAR

et al. 2022

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A standard method for distance determination is light detection and ranging (LiDAR), which relies on the emission and detection of reflected laser pulses. When LiDAR systems become common for every vehicle, many simultaneous laser signals will produce mutual LiDAR interference between LiDAR systems. In this paper, we analyze the possibility to recognize mutual interference in time-correlated single photon counting (TCSPC) LiDAR with particular focus on flash systems. We evaluate the LiDAR interference appearance by deriving the expected event distribution for ego and aggressor signal. From that, we calculate the probability of photon detection within each measured signal. This paper shows the high potential of different pulse repetition frequencies to reduce LiDAR interference. Using signal-to-noise ratio (SNR), we define the extinction distance, beyond which the aggressor signal completely extinguishes the ego signal. Applied on different background and laser event rates, we find the connection between ideal LiDAR system designs and lowest probability for unrecognized LiDAR interference. Furthermore, we show the relationship to a specific LiDAR design, which must fulfill eye safety condition and receives lower intensities with increasing target distances. Finally, we present different solutions for the recognition and reduction of LiDAR interference based on our previous results. Index Terms-Light detection and ranging (LiDAR), mutual LiDAR interference, time-correlated single-photon counting (TCSPC), direct time-of-flight (dTOF).

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Section: A Signal-to-noise Ratiomentioning

confidence: 99%

Section: B Reduction Of Lidar Interferencementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Probability of Unrecognized LiDAR Interference for TCSPC LiDAR

et al. 2022

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“…SPADs are not able to measure these temporal modulations within one measurement due to the first-photon principle causing the pile-up effect. Therefore, CDMA with dual-pulse emission considering dead time [17], PPM [18]- [23] or a combination of both methods is suggested [24]. [9], [10] IV.…”

Section: Related Workmentioning

confidence: 99%

Optimized Interference Suppression for TCSPC LiDAR

et al. 2022

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The increased use of light detection and ranging (LiDAR) systems for distance determination requires the investigation of mutual interference. In this paper, we describe the conditions for occurrence of LiDAR interference. We outline suppression methods for different LiDAR types identifying pulse-position modulation (PPM) as solution for time-of-flight LiDAR with time-correlated single photon counting (TCSPC) histograms. Based on PPM, we present a suppression method, which randomly varies the laser pulse emission times. For optimal suppression, we switch on the suppression only when interference is present. To recognize the occurrence of LiDAR interference, we develop a multi-pulse detection algorithm that can also extract all pulse positions. Simulations show that the algorithm can be applied for a signal-to-noise ratio greater than 3. Determining the heights of all recognized pulse signatures, an appropriate suppression level can be chosen. We successfully show the optimized interference suppression for an example LiDAR measurement. For a safe use by multiple systems, we suggest random numbers. We reuse the TCSPC histograms to generate random numbers, whose generation probability is calculated theoretically and confirmed by simulation and measurement data. For nearly all histogram distributions consisting of background-and laser-generated data, a sufficient amount of random numbers is produced.

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“…However, the background-light and dark counting will prevent the detector from reaching the desired detection ability. Accumulating multiple pulses technique was proposed to improve the detection probability and signal-to-noise ratio by several researchers [4,5,6]. However, the accumulation numbers of pulses will affect the speed and efficiency of detection, which makes the Lidar unsuitable for the detection of high-dynamic targets.…”

Section: Introductionmentioning

confidence: 99%

Improving the Performance of Pseudo-Random Single-Photon Counting Ranging Lidar

Liu

Chen

2019

Sensors

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A new encoding method is proposed to improve the performance of pseudo-random single-photon counting ranging (PSPCR) Lidar. The encoding principle and methodology are presented. In addition, the influence of detector’s dead time on the detection probability is analyzed with theoretical derivation and Monte Carlo simulation. Meanwhile, we propose using macro code as the analysis unit to quantitatively analyze the detection probability and single-photon detection efficiency of the traditional PSPCR Lidar and the modulated PSPCR Lidar. The Monte Carlo simulation and experiment prove that the proposed method exhibited better ranging performance than the traditional PSPCR Lidar system.

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Optimal pseudorandom pulse position modulation ladar waveforms

Cited by 6 publications

References 5 publications

Probability of Unrecognized LiDAR Interference for TCSPC LiDAR

Probability of Unrecognized LiDAR Interference for TCSPC LiDAR

Optimized Interference Suppression for TCSPC LiDAR

Improving the Performance of Pseudo-Random Single-Photon Counting Ranging Lidar

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