Wideband radar systems, apparatuses, and methods
Radar signals are generated to have signal characteristics that define multiple sub-pulses in each of a plurality of pulse repetition intervals (PRIs) of a single radar dwell. Electromagnetic radiation is emitted according to the radar signals and the emitted electromagnetic radiation is sensed as radar return signals over a receive interval in each PRI. Coherent integration is performed on a set of the radar return signals and non-coherent integration is performed on another set of the radar return signals.
1. A radar apparatus comprising:
a waveform generator configured to generate radar signals having signal characteristics that define multiple sub-pulses in each of a plurality of pulse repetition intervals (PRIs) of a single radar dwell;
an antenna communicatively coupled to the waveform generator and configured to emit electromagnetic radiation according to the radar signals;
a receiver communicatively coupled to the antenna and configured to sense the emitted electromagnetic radiation as radar return signals over a receive interval in each PRI; and
a signal processor communicatively coupled to the receiver and configured to perform coherent integration on a set of the radar return signals and non-coherent integration on another set of the radar return signals.
2. The radar apparatus of claim 1 , wherein the signal characteristics establish a set of the sub-pulses that are at a constant carrier frequency across the PRIs of the radar dwell, and another set of the sub-pulses are separated in frequency across the PRIs of the radar dwell.
3. The radar apparatus of claim 2 further comprising a multiplexer communicatively coupled to the receiver and configured to:
separate the radar return signals in accordance with the signal characteristics of the corresponding sub-pulses; and
provide the separated radar return signals to respective detection processing chains in which the radar return signals corresponding to the constant carrier sub-pulses are coherently integrated and the radar return signals corresponding to the frequency-separated sub-pulses are non-coherently integrated.
4. The radar apparatus of claim 3 , wherein the signal characteristics include pulse compression modulation and the detection processing chains include respective filters matched to the pulse compression modulation of each sub-pulse.
5. The radar apparatus of claim 3 , wherein the detection processing chains determine an unambiguous range to target from radar return signals that arrive subsequent to the receive interval of at least one PRI in which the corresponding sub-pulse was transmitted.
6. The radar apparatus of claim 1 , wherein the sub-pulses in each PRI are temporally adjacent.
7. The radar apparatus of claim 6 , wherein the sub-pulses in each PRI are frequency-separated.
8. A radar method comprising:
generating radar signals having signal characteristics that define multiple sub-pulses in each of a plurality of pulse repetition intervals (PRIs) of a single radar dwell, the signal characteristics establishing a set of the sub-pulses that are at a constant carrier frequency across the PRIs of the radar dwell, and another set of the sub-pulses are separated in frequency across the PRIs of the radar dwell;
emitting electromagnetic radiation according to the radar signals;
sensing the emitted electromagnetic radiation as radar return signals over a receive interval in each PRI; and
performing coherent integration on a set of the radar return signals and non-coherent integration on another set of the radar return signals.
9. The radar method of claim 8 further comprising:
separating the radar return signals in accordance with the signal characteristics of the corresponding sub-pulses;
coherently integrating the radar return signals corresponding to the constant carrier sub-pulses; and
non-coherently integrating the radar return signals corresponding to the frequency-separated sub-pulses.
10. The radar method of claim 9 further comprising:
filtering the radar return signals with filters matched to pulse compression modulation imparted on each sub-pulse.
11. The radar method of claim 9 further comprising:
determining an unambiguous range to target from radar return signals that arrive subsequent to the receive interval of at least one PRI in which the corresponding sub-pulse was transmitted.
12. The radar method of claim 8 , wherein the sub-pulses in each PRI are temporally adjacent.
13. The radar method of claim 12 , wherein the sub-pulses in each PRI are frequency-separated.
14. A tangible, non-transitory computer readable medium having encoded thereon processor instructions that when executed by one or more processors of a radar compels the radar to:
generate radar signals having signal characteristics that define multiple sub-pulses in each of a plurality of pulse repetition intervals (PRIs) of a single radar dwell;
emit electromagnetic radiation according to the radar signals;
sense the emitted electromagnetic radiation as radar return signals over a receive interval in each PRI; and
perform coherent integration on a set of the radar return signals and non-coherent integration on another set of the radar return signals.
15. The computer readable medium of claim 14 further comprising processor instructions that when executed by the one or more processors of the radar compels the radar to:
establish by the signal characteristics a set of the sub-pulses that are at a constant carrier frequency across the PRIs of the radar dwell and another set of the sub-pulses are separated in frequency across the PRIs of the radar dwell.
16. The computer readable medium of claim 15 further comprising processor instructions that when executed by the one or more processors of the radar compels the radar to:
separate the radar return signals in accordance with the signal characteristics of the corresponding sub-pulses;
coherently integrate the radar return signals corresponding to the constant carrier sub-pulses; and
non-coherently integrate the radar return signals corresponding to the frequency-separated sub-pulses.
17. The computer readable medium of claim 16 further comprising processor instructions that when executed by the one or more processors of the radar compels the radar to:
filter the radar return signals with filters matched to pulse compression modulation imparted on each sub-pulse.
18. The computer readable medium of claim 16 further comprising processor instructions that when executed by the one or more processors of the radar compels the radar to:
determine an unambiguous range to target from radar return signals that arrive subsequent to the receive interval of at least one PRI in which the corresponding sub-pulse was transmitted.
19. The computer readable medium of claim 14 , wherein the sub-pulses in each PRI are temporally adjacent.
20. The computer readable medium of claim 14 , wherein the sub-pulses in each PRI are frequency-separated.