Time of Flight Measurement Apparatus Pulse Rate
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Solution Overview
Problem
Conventional LIDAR systems are limited by the serial nature of pulse transmission and reception, restricting the rate at which pulses of light can be sent and received, which is particularly significant at higher altitudes where the speed of light limits the maximum pulse rate.
Innovation Solution
A time of flight measurement apparatus that transmits multiple pulses of light simultaneously, with circuitry to measure the elapsed time between transmission and reception of each pulse, allowing for increased pulse rates by sending subsequent pulses before the previous ones are received, thereby increasing the number of range measurements within a given time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pulses of light are transmitted serially one after another, then the system can reliably receive return signals, but the pulse rate is limited by the speed of light and cannot be increased
Solution Approach 1:
The system transmits multiple pulses of light simultaneously rather than serially, preparing and sending multiple measurements in advance so that return signals from earlier pulses are still being received while new pulses are transmitted. This preliminary action allows the pulse rate to exceed the speed of light limitation.
Solution Approach 2:
The invention transitions from a single-dimensional sequential pulse transmission approach to a multi-dimensional parallel transmission approach, where multiple pulses are sent simultaneously in different temporal slots, effectively adding a time dimension to the measurement process.
2Productivity
If multiple pulses are transmitted simultaneously to increase pulse rate, then the number of range measurements increases, but the system complexity increases
Solution Approach 1:
The system segments the pulse transmission process into multiple independent parallel channels, each handling a specific pulse. This segmentation allows simultaneous transmission of multiple pulses while maintaining manageable complexity through modular circuit design.
Solution Approach 2:
The invention uses copying by creating multiple identical pulse transmission paths that operate simultaneously, where each path is a copy of the basic transmit-receive unit, allowing parallel processing without requiring fundamentally new complex circuitry.
3Productivity
If pulses are sent at high rates, then data collection efficiency improves, but the speed of light limits the maximum pulse rate
Solution Approach 1:
The system maintains continuous useful action by overlapping the transmission and reception phases, where pulses are transmitted continuously at high rates while return signals from previous pulses are still being received, eliminating idle time and maximizing data collection efficiency.
Solution Approach 2:
By transmitting multiple pulses in advance and having them overlap in time, the system performs preliminary actions that allow the pulse transmission to continue at high rates without being constrained by the speed of light limitation on sequential transmission.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach doubles or triples the maximum pulse rate for a given flying height, enabling more efficient data collection and higher resolution terrain mapping, especially at higher altitudes where conventional systems are restricted.
Implementation Method 1
A time of flight measurement apparatus includes a laser configured to transmit light
Implementation Method 2
an optical receiver configured to receive light
Implementation Method 3
The range to the surface is determined by measuring the time delay between transmission of a pulse of light and detection of a corresponding reflection signal
Implementation Method 4
These pulses of light are reflected by the ground and/or objects upon the ground
Data Source
AI summary
An apparatus for measuring distance to a surface is disclosed. The apparatus transmits at least one subsequent pulse of light prior to receiving a reflection of a previously sent pulse of light. Thus, multiple pulses of light are in-flight at a given time. The embodiments are applicable to terrain mapping, bathymetry, seismology, detecting faults, biomass measurement, wind speed measurement, temperature calculation, traffic speed measurement, military target identification, surface to air rangefinding, high definition survey, close range photogrammetry, atmospheric composition, meteorology, distance measurement, as well as many other applications. Examples of such apparatuses include laser ranging systems, such as light detection and ranging (LIDAR) systems, and laser scanners. Data received from the apparatus by a data processing unit can be used to create a data model, such as a point cloud, digital surface model or digital terrain model describing the surface, terrain, and/or objects.