Pulse Radar Fill Level Measurement Extra-Range Echo Detection
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Solution Overview
Problem
Existing pulse radar-based fill-level measuring devices struggle to reliably detect extra-range echoes, which can lead to erroneous fill level measurements due to their high pulse-repetition rate and inability to distinguish these echoes from valid reflections.
Innovation Solution
The method involves transmitting microwave pulses at two different center frequencies with varying repetition rates and introducing a delay corresponding to half the wavelength, allowing for the differentiation of extra-range echoes by comparing travel times and attenuating their signal strength through averaging, thereby ensuring accurate fill level determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high pulse-repetition rate is used in pulse radar-based fill-level measuring devices, then measurement frequency and productivity are improved, but extra-range echoes cannot be distinguished from valid reflections leading to measurement errors
Solution Approach 1:
The patent applies periodic action by using two different pulse repetition rates (first and second repetition rates) in alternating measuring cycles. This allows the system to maintain high productivity through frequent measurements while reliably detecting extra-range echoes by comparing results from both repetition rates, thus resolving the contradiction between measurement frequency and measurement accuracy.
2Reliability
If reference measurement is performed to detect disturbance echoes, then stationary disturbing bodies can be recognized, but extra-range echoes resulting from multiple reflections cannot be reliably detected
Solution Approach 1:
The patent applies dynamics by making the pulse repetition rate variable rather than fixed. By alternating between two different repetition rates, the system dynamically adapts to detect both stationary disturbance echoes (through reference measurement) and extra-range echoes (through comparison of travel times at different repetition rates), thereby improving both reliability and adaptability.
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 effectively reduces the impact of extra-range echoes, ensuring accurate fill level measurements by distinguishing them from valid reflections and attenuating their signal strength, thus preventing erroneous readings.
Implementation Method 1
The microwave pulses transmitted toward the fill substance are reflected on the surface of the fill substance. The reflected echo pulses are then received back after a travel time dependent on the fill level.
Implementation Method 2
Fill level is ascertained based on the travel time.
Implementation Method 3
short microwave pulses are sent periodically toward the fill substance with a predetermined repetition rate, e.g. a repetition rate in an order of magnitude of 1 to 10 MHz, and with center frequencies in the gaga hertz range.
Data Source
AI summary
A method for determining the fill level of a fill substance located in a container. The method, which is based on the pulse travel time principle, is distinguished by the fact that extra-range echos can be recognized. For this, the method includes two method portions, in which microwave pulses are transmitted in the direction of the surface of the fill substance with different repetition rates in measuring cycles following one after the other. In each method portion, travel times are ascertained. The fill level is ascertained based on the first travel time and/or based on the second travel time, to the extent that they approximately agree. Otherwise, it is assumed that such echo pulses concern extra-range echos. Thus, by means of the method of the invention, it can be assured for pulse radar-based fill-level measurements that extra-range echos do not result in erroneous fill level values.