Abstract:
The present invention relates to a digital frequency modulated continuous wave (FMCW) radar altimeter and an altitude search method thereof. The FMCW includes: a transmitter that includes a direct digital synthesizer to create the FMCW using the digital synthesizer, and transmits the created FMCW in the form of a transmission signal onto the ground surface; a receiver that receives a reception signal reflected from the ground surface, mixes the reception signal and the transmission signal with each other to create a bit frequency signal having a differential frequency between the two signals, and converts the bit frequency signal into a digital signal; and a signal processing unit that detects the distance from the ground surface using the converted digital signal and outputs the detected distance. The signal processing unit divides a whole section from the minimum distance to the maximum distance into m sections and sets mutually different reference distances to the m sections. The signal processing unit controls the direct digital synthesizer to create an FMCW having a modulation bandwidth corresponding to the n^th reference distance during the unit time based on the n^th reference distance set to the n^th section among the m sections. The signal processing unit detects the distance from the ground surface using the modulation bandwidth corresponding to the converted digital signal and the n^th distance. The n is in the range of 1 to m to detect the distance from the ground surface.
Abstract:
PURPOSE: An FMCW radio altimeter having a wide altitude range and small measurement error and an altitude meauring method thereof are provided to determine an altitude in a wide altitude range with a small measurement error at a time, and counteract signal jamming by enabling frequency hopping. CONSTITUTION: A transceiver (200) comprises an offset frequency generator (210), an RF signal generator (240), an I/Q modulator (220), a transmission/reception separator (230), and a frequency mixer (250). The offset frequency generator deviates a frequency as much as a variable offset frequency that is set according to a control signal from an control operator (400). The RF signal generator generates an FMCW signal. The I/Q modulator performs frequency up-conversion by mixing an output signal from the offset frequency generator with an output signal from the RF signal generator. The transmission/reception separator separates signals that are transmitted from or received in an antenna unit (300). The frequency mixer generates a beat frequency by mixing an output signal from the RF signal generator with a signal received through an antenna.
Abstract:
The present invention relates to a proximity fuse sensor, and more specifically, to a full-wave proximity fuse sensor for direction finding to find the direction of an air target moving at a high speed by transmitting and receiving radio signals, and a method thereof. According to the full-wave proximity fuse sensor for direction finding and the method thereof, it is possible to find the distance range and the direction of an air target moving at high speed by transmitting and receiving signals which are digitally phase-modulated through the bi-phase shift keying method and applying a code correlation technique and a direction finding algorithm with multiple range gates. [Reference numerals] (AA) Start; (BB) End; (S100) Receive a target reflection signal in Ant #1, #3, #5; (S200) Select an antenna with maximum range gate receiving power; (S300) Select a range gate with maximum receiving power among antennae; (S400) Select a subdivided antenna from the antenna and the range gate; (S500) Receive a signal in the selected subdivided antenna and an adjacent antenna; (S600) Compare the receiving power of the selected antenna and the adjacent antenna; (S700) Determine the direction