OFDM Radar Repeater Frequency Shift Orthogonality
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Solution Overview
Problem
Current OFDM radar systems face challenges in distinguishing and evaluating monostatic and bistatic radar responses effectively, leading to interference and reduced signal strength due to the lack of orthogonality between signal paths.
Innovation Solution
The implementation of a repeater unit that modulates the received signal by shifting its frequency by a predefined frequency shift, creating orthogonality between monostatic and bistatic signal portions, allowing for separate evaluation and minimizing phase jitter, thus enabling precise target positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a repeater retransmits radar signals without modulation, then signal coverage is extended, but monostatic and bistatic signal paths interfere with each other due to lack of orthogonality
Solution Approach 1:
The repeater applies frequency shifting modulation to the retransmitted signal, changing the frequency parameter to create an orthogonal relationship between monostatic and bistatic signal paths. This allows both signal types to coexist without interference while maintaining extended coverage.
Solution Approach 2:
The signal spectrum is segmented into orthogonal components through frequency shifting. Monostatic and bistatic signals are separated into distinct frequency domains, allowing independent evaluation of each signal type without mutual interference.
2Loss of time
If monostatic and bistatic radar responses are evaluated simultaneously without signal separation, then processing time is reduced, but measurement precision decreases due to signal interference
Solution Approach 1:
By changing the frequency parameter through modulation in the repeater, monostatic and bistatic signals are distinguished by their frequency characteristics. This enables simultaneous evaluation of both signal types with high precision, as they can be separated in the frequency domain during processing.
3Length of stationary object
If repeater signal strength is increased to overcome attenuation, then transmission distance is extended, but phase jitter increases reducing positioning accuracy
Solution Approach 1:
The frequency shifting modulation applied by the repeater creates an orthogonal signal that can be independently processed. This approach maintains adequate signal strength for extended transmission while the orthogonality enables precise separation and processing, minimizing phase jitter effects on positioning accuracy.
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 allows for the separation and evaluation of monostatic and bistatic signal portions without interference, enhancing the accuracy of radar target positioning and reducing signal attenuation, particularly in short-range applications.
Implementation Method 1
the repeater is configured to modulate a signal generated and transmitted by the OFDM radar sensor into a signal orthogonal to the signal received by the repeater
Implementation Method 2
the OFDM radar sensor being configured to separate a portion of a signal received by the OFDM radar sensor, which portion corresponds to the modulated signal, from a monostatic portion of the signal received by the OFDM radar sensor
Implementation Method 3
a distance of a radar object may be estimated in light of the travel time of the OFDM symbols
Implementation Method 4
a speed estimate may be made in light of a phase characteristic over a sequence of OFDM symbols; the phase characteristic resulting from the Doppler effect
Data Source
AI summary
An OFDM radar sensor system having a plurality of transmitting and receiving units. One of the transmitting and receiving units is an OFDM radar sensor, and another of the transmitting and receiving units is a repeater which is configured to modulate a signal generated and transmitted by the OFDM radar sensor and received by the repeater into a signal orthogonal to the signal received by the repeater and to emit the modulated signal. The OFDM radar sensor is configured to separate a portion of a signal received by the OFDM radar sensor, which portion corresponds to the modulated signal, from a monostatic portion of the signal received by the OFDM radar sensor.