Patent ID: 9081085
Filing Date: 2015-07-14
Classification: G01S

Abstract:
1. A spread spectrum radar apparatus that detects an object by use of a detection radio wave that is spectrum-spread, the spread spectrum radar apparatus comprising: a transmission circuit that generates a spread spectrum signal and radiates the spread spectrum signal as the detection radio wave, the spread spectrum signal being spectrum-spread by combining an oscillating signal and a first pseudo noise code; a reception circuit that receives the detection radio wave reflected back from the object as a reception signal, extracts, based on (i) a second pseudo noise code obtained by time-delaying the first pseudo noise code and (ii) the oscillating signal, a signal of a specific frequency band from a despread output of the reception signal, and generates baseband signals by separating the extracted signal by distance, each of the distances corresponding to an amount of time delay between the first pseudo noise code and the second pseudo noise code; a Doppler filter that, for each of the distances, discriminates a time series of the baseband signals based on Doppler frequencies to output output signals, each of which indicates a strength and is associated with one of the distances and one of the Doppler frequencies, the Doppler frequencies each being a difference between a frequency of the detection radio wave radiated from the transmission circuit and a frequency of the detection radio wave received by the reception circuit; a removal unit that includes a plurality of threshold processing units provided corresponding to the Doppler frequencies resulting from the discrimination and is configured to remove an unwanted signal from the output signals output by the Doppler filter; and an estimation unit configured to estimate a position and a speed of the object from the output signals removed of the unwanted signal, wherein each of the threshold processing units is configured to calculate a threshold value for a corresponding one of the Doppler frequencies using a peak value which is a maximum value of the output signals in a range of distance corresponding to a detection area for the object, and determine the output signals in the range of distance that are no greater than the calculated threshold value to be the unwanted signal.