Successive signal interference mitigation
A radar system for a vehicle includes a transmitter, a receiver, and an interference mitigator. The transmitter transmits radio signals. The receiver receives radio signals. The received radio signals include transmitted radio signals reflected from objects. The receiver also processes the received radio signals to produce a sample stream. The interference mitigator successively (i) generates respective signals corresponding to the transmitted radio signals that are reflected from each of a plurality of objects, and (ii) adds the respective signals to the sample stream to form a modified sample stream. The addition of the respective signals removes interference from the sample stream due to the transmitted radio signals reflected from the plurality of objects. The receiver is configured to use the modified sample stream to detect a first object at a first range which is more distant than respective ranges of the plurality of objects.
1. A radar sensing system for a vehicle, the radar sensing system comprising:
a transmitter configured for installation and use on a vehicle, and configured to transmit radio signals;
a receiver configured for installation and use on the vehicle, and configured to receive radio signals that include the transmitted radio signals reflected from objects in the environment;
an interference mitigation processor;
wherein the receiver is configured to process and digitize the received radio signals to produce a sample stream;
wherein the sample stream is provided to the interference mitigation processor;
wherein the interference mitigation processor is configured to successively (i) generate respective signals corresponding to selected signals of the received radio signals that are the transmitted radio signals reflected from respective ones of a selected plurality of objects, and (ii) add the respective signals to the sample stream to form a modified sample stream, and wherein the addition of the respective signals removes from the sample stream those selected signals that are the transmitted radio signals reflected from the selected plurality of objects; and
wherein the receiver is configured to use the modified sample stream to detect a first object at a first range which is more distant than respective ranges of the selected plurality of objects because interfering radio signals, which are the transmitted radio signals reflected from the selected plurality of objects, have been removed from the modified sample stream.
2. The radar sensing system of claim 1 , wherein the interference mitigation processor is configured to (i) generate signals corresponding to the transmitted radio signals that are reflected from a particular object by determining estimates for the reflected radio signals associated with that particular object, (ii) determine estimates for parameters related to corresponding ones of the reflected radio signals, and (iii) generate complex samples corresponding to the transmitted radio signals reflected from that particular object.
3. The radar sensing system of claim 2 , wherein the estimates of the parameters include filters that produce running weighted averages of a plurality of past samples of the generated complex samples corresponding to a selected set of chips of the transmitter for a particular range or delay.
4. The radar sensing system of claim 2 , wherein the estimates of the parameters are updated using an error signal generated from previous estimates of the parameters and the modified sample stream.
5. The radar sensing system of claim 2 , wherein the estimates of the parameters comprise filters that produce exponentially weighted filtering of a plurality of past samples of the samples corresponding to a selected set of chips of the transmitter for a given range or delay.
6. The radar sensing system of claim 1 , wherein the interference mitigation processor is configured to further modify the modified sample stream based on the addition of additional signals corresponding to the transmitted radio signals reflected from one or more additional objects.
7. The radar sensing system of claim 1 , wherein the interference mitigation processor only modifies the sample stream for transmitted radio signals reflected from objects at ranges that are greater than a first threshold range value.
8. A radar sensing system for a vehicle, the radar sensing system comprising:
a transmitter configured for installation and use on a vehicle, and configured to transmit radio signals;
a receiver configured for installation and use on the vehicle, and configured to receive radio signals that include the transmitted radio signals reflected from objects in the environment;
an interference mitigation processor;
wherein the receiver is configured to process and digitize the received radio signals to produce a sample stream;
wherein the sample stream is provided to the interference mitigation processor;
wherein the interference mitigation processor is configured to successively (i) generate respective signals corresponding to selected signals of the received radio signals that are the transmitted radio signals reflected from respective ones of a selected plurality of objects, and (ii) add the respective signals to the sample stream to form a modified sample stream, and wherein the addition of the respective signals removes from the sample stream those selected signals that are the transmitted radio signals reflected from the selected plurality of objects;
wherein the receiver is configured to use the modified sample stream to detect a first object at a first range which is more distant than respective ranges of the selected plurality of objects; and
wherein the interference mitigation processor only modifies the sample stream for transmitted radio signals reflected from objects at ranges that are greater than a first threshold range value, and wherein the interference mitigation processor is bypassed for the effect of transmitted radio signals reflected from objects that are at ranges below a second threshold range value.
9. The radar sensing system of claim 8 , wherein the second threshold range value is less than the first threshold range value.
10. A radar sensing system for a vehicle, the radar sensing system comprising:
a plurality of transmitters configured for installation and use on a vehicle, and configured to transmit radio signals;
a plurality of receivers configured for installation and use on the vehicle, and configured to receive radio signals that include the transmitted radio signals reflected from objects in the environment;
an interference mitigation processor;
wherein a first receiver of the plurality of receivers is configured to process and digitize the received radio signals to produce a sample stream;
wherein the sample stream is provided to the interference mitigation processor;
wherein the interference mitigation processor is configured to successively (i) generate respective signals corresponding to selected signals of the received radio signals that are the transmitted radio signals reflected from a first object at a first selected range, and (ii) add the respective signals to the sample stream to form a modified sample stream, and wherein the addition of the respective signals removes from the sample stream those selected signals that are the transmitted radio signals reflected from the first object; and
wherein the first receiver is configured to use the modified sample stream to detect a second object at a second range that is more distant than the first range of the first object because interfering radio signals, which are the transmitted radio signals reflected from the first object, have been removed from the modified sample stream.
11. The radar sensing system of claim 10 , wherein each receiver of the plurality of receivers receives reflections of radio signals transmitted by each of the plurality of transmitters.
12. The radar sensing system of claim 10 , wherein the received radio signals comprise a sum of the reflected radio signals transmitted by each of the plurality of transmitters.
13. The radar sensing system of claim 10 , wherein the interference mitigation processor comprises a plurality of interference mitigation processors, and wherein the plurality of interference mitigation processors comprises an interference mitigation processor for each transmitter/receiver pair of the plurality of transmitters and the plurality of receivers.
14. The radar sensing system of claim 10 , wherein the interference mitigation processor is configured to successively remove selected samples from the sample stream that are attributed to radio signals reflected from the first object that were transmitted by each respective transmitter of the plurality of transmitters.
15. The radar sensing system of claim 10 , wherein the interference mitigation processor is configured to successively (i) determine estimates for the radio signals transmitted by each of the plurality of transmitters that are reflected from the first object at the first selected range, (ii) determine estimates for parameters of the corresponding reflected radio signals transmitted by each of the plurality of transmitters, and (iii) generate complex samples corresponding to the transmitted radio signals reflected from the first object, such that the sample stream is modified based on the samples corresponding to the transmitted radio signals reflected from the first object.
16. The radar sensing system of claim 15 , wherein the estimate of the parameters includes filters that produce running weighted averages of a plurality of past samples of the samples corresponding to a selected set of chips of the different transmitters for a range or delay associated with the first object.
17. The radar sensing system of claim 15 , wherein the estimates of the parameters are updated using an error signal generated from previous estimates of the parameters and an actual sample.
18. The radar sensing system of claim 15 , wherein the estimate of the parameters includes filters that produce exponentially weighted filtering of a plurality of past samples of the samples corresponding to a selected set of chips of the different transmitters for a range or delay associated with the first object.
19. A radar sensing system for a vehicle, the radar sensing system comprising:
a plurality of transmitters configured for installation and use on a vehicle, and configured to transmit radio signals;
a plurality of receivers configured for installation and use on the vehicle, and configured to receive radio signals that include the transmitted radio signals reflected from objects in the environment;
an interference mitigation processor;
wherein a first receiver of the plurality of receivers is configured to process and digitize the received radio signals to produce a sample stream;
wherein the sample stream is provided to the interference mitigation processor;
wherein the interference mitigation processor is configured to successively (i) generate respective signals corresponding to selected signals of the received radio signals that are the transmitted radio signals reflected from a first object at a first selected range, and (ii) add the respective signals to the sample stream to form a modified sample stream, and wherein the addition of the respective signals removes from the sample stream those selected signals that are the transmitted radio signals reflected from the first object;
wherein the first receiver is configured to use the modified sample stream to detect a second object at a second range that is more distant than the first range of the first object; and
wherein the interference mitigation processor is configured to only modify the sample stream for transmitted signals reflected from objects at ranges that are greater than a first threshold range value.
20. The radar sensing system of claim 17 , wherein the receiver is configured to bypass the interference mitigation processor and directly process the sample stream and detect the second object when the second object is at a distance less than a second threshold value.
21. A method for removing interference from a radio signal received by a vehicle radar sensing system, said method comprising:
providing a transmitter for installation and use on a vehicle, wherein the transmitter is configured to transmit radio signals;
providing a receiver configured for installation and use on the vehicle and configured to receive radio signals that include the transmitted radio signals reflected from objects in the environment;
processing the received radio signals to produce a sample stream;
successively (i) generating respective signals corresponding to the transmitted radio signals that are reflected from respective ones of a selected plurality of objects, and (ii) adding the respective signals to the sample stream to form a modified sample stream, wherein the addition of the respective signals removes from the sample stream those signals that correspond to the transmitted radio signals reflected from the selected plurality of objects; and
using the modified sample stream, detecting a first object at a first range which is more distant than respective ranges of the selected plurality of objects because interfering radio signals, which are the transmitted radio signals reflected from the selected plurality of objects, have been removed from the modified sample stream.
22. The method of claim 21 , wherein generating an signal corresponding to the transmitted radio signals that are reflected from each of a plurality of objects comprises determining estimates for the transmitted radio signals reflected from a first object, determining estimates for parameters related to corresponding ones of the transmitted radio signals reflected from the first object, and generating complex samples corresponding to the transmitted radio signals reflected from the first object to form an sample stream.
23. The method of claim 22 , wherein determining estimates of the parameters comprises producing running weighted averages of a plurality of past samples of the generated complex samples corresponding to a selected set of chips of the transmitter for a particular range or delay.
24. The method of claim 22 , wherein the estimates of the parameters are updated using an error signal generated from previous estimates of the parameters and the modified sample stream.
25. The method of claim 22 , wherein determining estimates of the parameters includes producing exponentially weighted filtering of a plurality of past samples of the samples corresponding to a selected set of chips of the transmitter for a given range or delay.