Radar apparatus
An embodiment of the present invention relates to a radar apparatus, wherein a distance to a target and a velocity of the target are measured by transmitting a digitally modulated transmitting signal using a digital code and receiving and demodulating an echo signal returned due to reflection of the transmitting signal from the target.
1. A radar apparatus, comprising:
a transmitter configured to transmit a digitally modulated transmitting signal;
a receiver configured to receive an echo signal outputted by the transmitter and reflected by an object; and
a digital signal processor configured to demodulate the echo signal to measure a distance to the object,
wherein the digitally modulated transmitting signal is configured to include a plurality of packets, each packet including a distance code for measuring the distance, the distance codes included in each packet having correlation with one another, and
wherein the correlation indicates a degree of a code space between the distance codes included in each packet.
2. The radar apparatus of claim 1 , wherein the each packet further includes at least one segment and the plurality of packets are sequentially transmitted.
3. The radar apparatus of claim 2 , wherein each packet included in the digitally modulated transmitting signal further includes a preamble for synchronization of signals.
4. The radar apparatus of claim 3 , wherein the digital signal processor calculates a time interval between the time at transmitting the signal and a current time based on the correlation between distance codes included in the echo signal of the transmitting signal and the distance codes included in the transmitting signal at the current time, and
calculates the distance to the object based on the calculated time interval.
5. The radar apparatus of claim 3 , wherein each packet further includes a data segment for communicating data between different radar apparatuses.
6. The radar apparatus of claim 1 , wherein the digital signal processor further calculates a velocity of the object based on a change in a Doppler frequency of the echo signals or based on a change in the distance to the object per a time interval by measuring the distance to the object at a predefined time interval.
7. The radar apparatus of claim 1 , wherein the transmitting signal includes unique identification codes for identifying each radar apparatus and each radar apparatus identifies its own echo signal by the identification codes.
8. The radar apparatus of claim 1 , wherein the
transmitter converts a digital modulation signal generated by the digital signal processor into an analog signal and transmits the signal through a transmit antenna by up-converting the signal to a carrier frequency.
9. The radar apparatus of claim 8 , wherein the transmitter includes:
a digital-to-analog converter configured to convert the digitally modulated signal into the analog signal in a baseband;
an oscillator configured to generate the carrier signal;
a transmit mixer configured to convert the analog signal in the baseband into an analog signal of which the central frequency is the carrier frequency by using the carrier signal; and
a power amplifier configured to generate the transmitting signal by amplifying an output signal of the transmit mixer.
10. The radar apparatus of claim 8 , wherein the receiver includes:
a low noise amplifier configured to amplify the echo signals received through a receive antenna;
a mixer configured to convert the output signal of the low-noise amplifier into the analog signal in the baseband; and
an analog-to-digital converter configured to convert the output signal of the mixer into the digital signal.
11. The radar apparatus of claim 9 , wherein each packet further includes at least one segment and the plurality of packets are sequentially transmitted.
12. The radar apparatus of claim 10 , wherein each packet included in the digitally modulated transmitting signal further includes a preamble for synchronization of signals.
13. The radar apparatus of claim 12 , wherein the digital signal processor calculates a time interval between the time at transmitting the signal and a current time based on the correlation between distance codes included in the echo signal of the transmitting signal at the first time and the distance codes included in the transmitting signal at the current time, and
calculates the distance to the object based on the calculated time interval.
14. The radar apparatus of claim 9 , wherein the digital signal processor further calculates a velocity of the object based on a change in a Doppler frequency of the echo signals or based on a change in the distance to the object per a time interval by measuring the distance to the object at a predefined time interval.