Multi-PRF signal processor system

The method of claim 12 wherein said step of converting data sets into velocity bands is characterized by the relationships:

• ##EQU6## where subscript x identifies the data sets (1 or 2) A.sub.x = the velocity band
• Int = the integer of the expression in parenthesis ##EQU7## n.sub.x = the filter output number N is the total number of filters in said filter bank,
• F.sub.x is the pulse repetition frequency, and
• f.sub.B is the frequency width of a velocity band.

In a multi PRF doppler radar system for determining the velocity of a target including means for controlling the PRF and modifying the PRF at predetermined intervals, a return signal processor comprising:

• a doppler filter bank connected to said return signal and providing a signal at one of said filters in said bank,
• a temporary storage device connected to said filter bank and to said PRF controlling means for storing data sets comprising the said one filter number and the corresponding PRF for at least two different PRF values,
• means for converting any two data sets in said storage device into a first velocity indication and second velocity indication,
• means for resolving said first and second velocity indications into a single unambiguous velocity indication of said target velocity.

In a doppler pulse echo system for determining the velocity of a target of the type including a transmitter for transmitting a series of energy pulses toward said target at a predetermined pulse repetition frequency (PRF), a receiver for receiving a pulse echo signal reflected by said target and a signal processing device having a doppler filter bank including a plurality of filter circuits, the method for determining the doppler frequency representative of the target velocity including the steps of:

• separating the doppler spectrum into a plurality of velocity bands of predetermined frequency width,
• modifying the PRF at predetermined intervals according to a predetermined pattern of at least three different PRF ratios,
• storing data sets comprising the identities of the specific filter circuit which produces an output signal and the PRF ratio of the transmitted signal at which said output signal is produced,
• converting the first data set at one PRF to one of said velocity bands, converting another data set at a different PRF to one of said velocity bands, determining from said velocity bands a single unambiguous velocity band which satisfies each of said data sets, and
• determining the target velocity according to the doppler frequency represented by said unambiguous velocity band.