Multiple parameter doppler radar

• US 4,740,045 A
• Filed: 07/02/1986
• Issued: 04/26/1988
• Est. Priority Date: 07/02/1986
• Status: Expired due to Term

• Current Assignee: Goodson and Associates Incorporated
• Original Assignee: Goodson and Associates Incorporated
• Inventors: Goodson, William D., Alden, John R.
• Primary Examiner(s): Tubbesing, T. H.
• Application Number:
  US06/881,831
• Time in Patent Office: 664 Days
• Field of Search: 342/109, 342/112, 342/114, 342/115, 342/173
• US Class Current: 342/112
• CPC Class Codes: G01S 13/584 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/60 wherein the transmitter and receiver are mounted on the moving object, e.g. for determining ground speed, drift angle, ground track G01S13/64 takes precedence
• CPC Class Codes: G01S 13/62 Sense-of-movement determination G01S13/589 takes precedence
• CPC Class Codes: G01S 13/92 for velocity measurement
• CPC Class Codes: G01S 7/023 Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36
• CPC Class Codes: G01S 7/0236 Avoidance by space multiplex

Abstract

A multiple parameter doppler radar system transmits a radar signal which is alternated between a first and second frequency toward a target. The doppler shifted signals reflected from the target are received and processed to derive a pair of doppler signals related respectively to the first and second frequency signals. The frequency of one of the doppler signals is measured and scaled to a target speed. The phase magnitude between the two doppler signals is measured and scaled to a target range. The phase lead/lag relationship of the two doppler signals is detected to determine if the target is moving toward or away from the radar system. The components of the system are controlled by a microprocessor which is programmed to perform quality determinations on the data derived from the signals to assess the reliability of the data even in a multiple target environment prior to displaying the parameters of target motion.

Claims

1. A method of remotely determining a parameter of motion of a moving target comprising the steps of:

(a) transmitting a radio frequency signal toward a moving target;

(b) receiving a target reflected signal which is said radio frequency signal as reflected from said target;

(c) processing said target reflected signal to derive a doppler signal including doppler pulses;

(d) establishing a variable window period extending between the beginning of one of said doppler pulses and the beginning of another of said doppler pulses; and

(e) processing said doppler signal over said variable window period to derive a parameter of motion of said target.

2. A method of remotely determining the speed, range, and relative direction of movement of a moving target comprising the steps of:

(a) transmitting a radio frequency siganl toward a moving target;

(b) receiving a target reflected signal which is said radio frequency signal as reflected from said target;

(c) processing said target reflected signal to derive a target range;

(d) processing said target reflected signal to derive a target speed;

(e) processing said target reflected signal to derive a relative target direction;

(f) displaying said target range and said target speed in selected dimensional units;

(g) displaying an indication of said relative target direction;

(h) periodically alternating the frequency of said radio frequency signal between a first frequency and a second frequency;

(i) converting a first component of said target reflected signal which is related to said first frequency to a first doppler signal;

(j) converting a second component of said target reflected signal which is related to said second frequency to a second doppler signal;

(k) measuring the phase angle of the phase difference between said first and second doppler signals;

(l) scaling said phase angle to said target range;

(m) alternating the frequency of said radio frequency signal between said first and second frequencies if said target range is greater than a selected range; and

(n) alternating the frequency of said radio frequency signal between a third frequency and a fourth frequency if said target range is not greater than said selected range.

3. A method of remotely determining the speed, range, and relative direction of a moving target comprising the steps of:

(a) transmitting a radio frequency signal which periodically alternates between a first frequency and a second frequency toward a moving target;

(b) receiving target reflected signals related respectively to said first and second frequencies;

(c) converting a target reflected signal related to said first frequency to a first doppler signal and a target reflected signal related to said second frequency to a second doppler signal;

(d) measuring the phase angle of the phase difference between said first and second doppler signals and scaling said phase angle to a target range by;

(i) digitally combining said doppler signals to isolate a range pulse having a pulse width proportional to said phase angle;

(ii) generating clock pulses;

(iii) gating said clock pulse to a range counter circuit with said range pulse such that the number of said clock pulses gated is proportional to said phase angle;

(iv) counting said clock pulses with said range counter circuit resulting in a range count;

(v) scaling said range count to said target range in selected dimensional units;

(e) measuring the doppler frequency of one of said doppler signals and scaling said doppler frequency to a target speed;

(f) detecting the phase lead/lag relationship between said doppler signals and converting said phase relationship to a relative target direction; and

(g) displaying said target range and said target speed.

4. A method as set forth in claim 3 including the step of:

(a) displaying an indication of said relative target direction.

5. A method as set forth in claim 3 including the steps of:

(a) selecting a set of target range limits; and

(b) displaying said target range only upon said target range falling within the selected set of target range limits.

6. A method as set forth in claim 3 including the steps of:

(a) deriving a plurality of said range counts;

(b) scaling each range count to an intermediate range parameter;

(c) comparing each current intermediate range parameter with the previous intermediate range parameter; and

(d) scaling said current range count to a current target range and displaying said current target range only if said current intermediate range parameter differs from said previous intermediate range parameter by less than a selected amount.

7. A method as set forth in claim 3 including the steps of:

(a) deriving a plurality of said relative target directions;

(b) comparing each current target direction with the previous target direction; and

(c) scaling said current range count to a current target range and displaying said current target range only if said current target direction is same as said previous target direction.

8. A method as set forth in claim 3 including the steps of:

(a) counting the pulses of said one of said doppler signals over a measured period of time resulting in a doppler count; and

(b) scaling said doppler count over said measured period to a target speed in selected dimensional units.

9. A method as set forth in claim 3 including the steps of:

(a) selecting a set of target range limits; and

(b) displaying said target speed only upon the corresponding target range falling within the selected set of target range limits.

10. A method of remotely determining the speed, range, and relative direction of a moving target comprising the steps of:

(a) transmitting a radio frequency signal which periodically alternates between a first frequency and a second frequency toward a moving target;

(b) receiving target reflected signals related respectively to said first and second frequencies;

(c) converting a target reflected signal related to said first frequency to a first doppler signal and a target reflected signal related to said second frequency to a second doppler signal;

(d) measuring the phase angle of the phase difference between said first and second doppler signals and scaling said phase angle to a target range;

(e) measuring the doppler frequency of one of said doppler signals and scaling said doppler frequency to a target speed by;

(i) generating clock pulses;

(ii) activating at the beginning of a doppler cycle a window counter which counts said clock pulses when activated to derive a window count;

(iii) activating a doppler counter which counts the pulses of said one of said doppler signals when activated to derive a doppler count;

(iv) enabling the deactivation of said window counter and said doppler counter upon the first to occur of said window counter reaching a selected terminal window count or said doppler counter reaching a selected terminal doppler counter;

(v) deactivating said window counter and said doppler counter at the beginning of the next doppler pulse of said one of said doppler signals after said enabling step;

(vi) computing a target speed from a combination of the window count and the doppler count which are current when said window and doppler counters are deactivated.

(f) detecting the phase lead/lag relationship between said doppler signals and converting said phase relationship to a relative target direction;

(g) displaying said target range and said target speed.

11. A method as set forth in claim 10 including the steps of:

(a) in response to the occurrence of each pulse of said one of said doppler signals while said window counter is activitated, reading said window counter and storing the current window count, the first such window count read being a first period count;

(b) subtracting each current window count from the previous window count, resulting in a current period count;

(c) differencing each current period count with said first period count, resulting in a respective period number;

(d) summing the absolute value of the period numbers while said window counter is activated, resulting in a signal quality number; and

(e) computing said target speed and displaying said target speed only if said signal quality number is less than a selected fraction of said window count when said window counter is deactivated.

12. A method as set forth in claim 11 including the step of:

(a) scaling a phase angle to a target range and displaying said target range only if the current target speed is displayable.

13. A method of remotely determining the speed, range, and relative direction of a moving target comprising the steps of:

(a) transmitting a radio frequency signal which periodically alternates between a first frequency and a second frequency toward a moving target;

(b) receiving target reflected signals related respectively to said first and second frequencies;

(c) converting a target reflected signal related to said first frequency to a first doppler signal and a target reflected signal related to said second frequency to a second doppler signal;

(d) measuring the phase angle of the phase difference between said first and second doppler signals and scaling said phase angle to a target range;

(e) alternating the frequency of said radio frequency signal between said first and second frequencies if said target range is greater than a selected range;

(f) alternating the frequency of said radio frequency signal between a third frequency and a fourth frequency if said target range is not greater than said selected range;

(g) measuring the doppler frequency of one of said doppler signals and scaling said doppler frequency to a target speed;

(h) detecting the phase lead/lag relationship between said doppler signals and converting said phase relationship to a relative target direction; and

(i) displaying said target range and said target speed.

14. A method of remotely determining the speed, range, and relative direction of a moving target comprising the steps of:

(a) transmitting a radio frequency signal which periodically alternates between a first frequency and a second frequency toward a moving target;

(b) receiving target reflected signals related respectively to said first and second frequencies;

(c) converting a target reflected signal related to said first frequency to a first doppler signal and a target reflected signal related to said second frequency to a second doppler signal;

(d) said first and second frequencies comprising a narrowest frequency pair and causing a selected range of phase difference between said first and second doppler signals to correspond proportionally to a set of longest target ranges, and including the steps of;

(i) determining a plurality of frequency pairs of successively wider frequency differences between said first and second frequencies which will cause said selected range of phase differences to correspond proportionally to a respective plurality of sets of successively shorter target ranges;

(ii) beginning with said narrowest frequency pair, alternating the frequency of said radio frequency signal between successively wider frequency pairs and for each frequency pair measuring said phase angle and said target range until said phase angle enters said selected range of phase differences;

(iii) determining if the measured target ranges are decreasing or increasing;

(iv) upon said measuring target ranges decreasing, alternating between successively wider frequency pairs to maintain said phase angle within said selected range of phase differences;

(v) upon said measured target ranges increasing, alternating between successively narrower frequency pairs to maintain said phase angle within said selected range of phase differences;

(e) using the difference between frequency pairs, and the phase difference between said first and second doppler signals and scaling to a target range;

(f) measuring the doppler frequency of one of said doppler signals and scaling said doppler frequency to a target speed;

(g) detecting the phase lead/lag relationship between said doppler signals and converting said phase relationship to a relative target direction; and

(h) displaying said target range and said target speed.

15. A method of remotely determining the speed, range, and relative direction of movement of a moving target comprising the steps of:

(a) transmitting a radio frequency signal from a moving platform vehicle toward a moving target;

(b) receiving a return signal on said platform vehicle, said return signal including a roadway reflected signal component which is said radio frequency signal as reflected from stationary objects along a roadway on which said platform vehicle is moving and a target reflected signal component which is said radio frequency signal as reflected from said target;

(c) isolating a roadway reflected signal and a target reflected signal from said return signal;

(d) processing said roadway reflected signal to derive;

(1) a platform speed with respect to said roadway; and

(2) a platform direction with respect to said roadway;

(e) processing said target reflected signal to derive;

(1) a target range with respect to said platform vehicle;

(2) a relative target speed with respect to said platform vehicle; and

(3) a target direction with respect to said platform vehicle;

(f) mathematically combining said relative target speed and said platform speed in a manner determined by the relationship of said target direction and said platform direction to derive an absolute target speed with respect to said roadway;

(g) displaying said platform speed, said absolute target speed, and said target range in selected dimensional units; and

(h) displaying an indication of said target direction.

16. A method of remotely determining the speed, range, and relative direction of movement of a moving target comprising the steps of:

(a) transmitting a radio frequency signal from a moving platform vehicle toward a moving target;

(b) receiving a return signal on said platform vehicle, said return signal including a roadway reflected signal component which is said radio frequency signal as reflected from stationary objects along a roadway on which said platform vehicle is moving and a target reflected signal component which is said radio frequency signal as reflected from said target;

(c) isolating a roadway reflected signal and a target reflected signal from said return signal by;

(i) bandpass filtering said return signal to isolate said roadpass reflected signal from said return signal;

(ii) low pass filtering said return signal to isolate a first target reflected signal related to a first class of targets from said return signal;

(iii) high pass filtering said return signal to isolate a second target reflected signal related to a second class of targets from said return signal;

(iv) electronically selecting one of said first and second target reflected signals;

(d) processing said roadway reflected signal to derive;

(1) a platform speed with respect to said roadway; and

(2) a platform direction with respect to said roadway;

(e) processing said target reflected signal to derive;

(1) a target range with respect to said platform vehicle;

(2) a relative target speed with respect to said platform vehicle; and

(3) a target direction with respect to said platform vehicle;

(f) mathematically combining said relative target speed and said platform speed in a manner determined by the relationship of said target direction and said platform direction to derive an absolute target speed with respect to said roadway;

(g) displaying said platform speed, said absolute target speed, and said target range in selected dimensional units; and

(h) displaying an indication of said target direction.

17. A method of remotely determining the speed, range, and relative direction of movement of a moving target comprising the steps of:

(a) transmitting a radio frequency siganl from a moving platform vehicle toward a moving target;

(b) receiving a return signal on said platform vehicle, said return signal including a roadway reflected signal component which is said radio frequency signal as reflected from stationary objects along a roadway on which said platform vehicle is moving and a target reflected signal component which is said radio frequency signal as reflected from said target;

(c) periodically alternating the frequency of said radio frequency signal between a first frequency and a second frequency;

(d) isolating a roadway reflected signal and a target reflected signal from said return signal;

(e) processing said roadway reflected signal to derive a platform speed with respect to said roadway by;

(1) converting a first component of said roadway reflected signal which is related to said first frequency to a first platform doppler signal;

(2) converting a second component of said roadway reflected signal which is related to said second frequency to a second platform doppler signal;

(3) measuring a platform doppler frequency of one of said platform doppler signals; and

(4) scaling said platform doppler frequency to a platform speed;

(f) processing said roadway reflected signal to derive a platform direction with respect to said roadway;

(g) processing said target reflected signal to derive;

(1) a target range with respect to said platform vehicle;

(2) a relative target speed with respect to said platform vehicle; and

(3) a target direction with respect to said platform vehicle;

(h) mathematically combining said relative target speed and said platform speed in a manner determined by the relationship of said target direction and said platform direction to derive an absolute target speed with respect to said roadway;

(i) displaying said platform speed, said absolute target speed, and said target range in selected dimensional units; and

(j) displaying an indication of said target direction.

18. A method as set forth in claim 17 wherein said platform direction is derived by:

(a) detecting the phase lead/lag relationship between said platform doppler signals; and

(b) converting said phase relationship to a platform direction.

19. A method of remotely determining the speed, range, and relative direction of movement of moving target comprising the steps of:

(a) transmitting a radio frequency signal from a moving platform vehicle toward a moving target;

(b) receiving a return signal on said platform vehicle, said return signal including a roadway reflected signal component which is said radio frequency signal as reflected from stationary objects along a roadway on which said platform vehicle is moving and a target reflected signal component which is said radio frequency signal as reflected from said target;

(c) isolating a roadway reflected signal and a target reflected signal from said return signal;

(d) processing said roadway reflected signal to derive a platform speed with respect to said roadway and a platform direction with respect to said roadway by;

(1) transmitting said radio frequency signal in a forward direction of said platform vehicle;

(2) processing said roadway reflected signal to derive a forward platform speed;

(3) transmitting said radio frequency signal in a rear direction of said platform vehicle;

(4) processing said roadway reflected signal to derive a rear platform speed;

(5) mathematically comparing said forward platform speed with said rear platform speed; and

(6) delaying the combining of one of said platform speeds with said relative target speed until said forward platform speed and said rear platform speed differ by less than a selected platform speed differential;

(e) processing said target signal to derive;

(1) a target range with respect to said platform vehicle;

(2) a relative target speed with respect to said platform vehicle; and

(3) a target direction with respect to said platform vehicle;

(f) mathematically combining said relative target speed and said platform speed in a manner determined by the relationship of said target direction and said platform direction to derive an absolute target speed with respect to said roadway;

(g) displaying said platform speed, said absolute target speed, and said target range in selected dimensional units; and

(h) displaying an indication of said target direction.

20. A method of remotely monitoring moving targets from a moving platform vehicle in a forward and rear direction and in a same direction lane and in an opposite direction lane as said platform vehicle and determining the speed, range, and relative direction of movement of said moving targets comprising the steps of;

(a) selecting a target violation speed;

(b) sequentially transmitting a radio frequency signal in each of a forward direction and a rear direction of signal transmission from a moving platform vehicle;

(c) receiving a return signal on said platform vehicle, said return signal including a roadway reflected signal component which is said radio frequency signal as reflected from stationary objects along a roadway on which said platform vehicle is moving and, if a moving target is present, a target reflected signal component which is said radio frequency signal as reflected from said target;

(d) for each of said forward and rear directions, sequentially processing said return signal to isolate, if present, a target reflected signal from a first class of target in a same direction lane as said platform vehicle and a second class of target in an opposite direction lane as said platform vehicle;

(e) for each isolated target reflected signal, isolating a corresponding roadway reflected signal from said return signal;

(f) processing each target reflected signal to derive;

(1) a target range with respect to said platform vehicle;

(2) a relative target speed with respect to said platform vehicle; and

(3) a target direction of motion with respect to said platform vehicle;

(g) processing each corresponding roadway reflected signal to derive;

(1) a corresponding platform speed with respect to said roadway; and

(2) a corresponding platform direction of motion with respect to said roadway;

(h) mathematically combining each relative target speed and said corresponding platform speed in a manner determined by the relationship of said target direction of motion and said corresponding platform direction of motion to derive an absolute target speed with respect to said roadway;

(i) comparing each absolute target speed with said target violation speed; and

(j) upon said absolute target speed exceeding said target violation speed;

(1) displaying an indication of said direction of signal transmission, said target violation speed, said absolute target speed, said target range, an indication of said target direction of motion, an indication of the class of target, and said corresponding platform speed; and

(2) generating an alert signal.

21. A method of remotely determining the speed, range, and relative direction of movement of a moving target comprising the steps of:

(a) transmitting a radio frequency signal from a moving platform vehicle toward a moving target in one of a forward platform direction or a rear platform direction with respect to said platform vehicle;

(b) receiving a return signal on said platform vehicle, said return signal being at least one of said radio frequency signal as reflected from stationary objects along a roadway on which said platform vehicle is moving or said radio frequency signal as reflected from said target;

(c) processing said return signal to derive at least a platform direction parameter indicating the relative direction of motion of said platform vehicle with respect to said roadway;

(d) upon said platform direction parameter indicating rearward motion of said platform vehicle and thereby indicating that said return signal was not reflected from said roadway;

(1) transmitting said radio frequency signal in an opposite platform direction;

(2) receiving an opposite return signal; and

(3) processing said opposite return signal to derive at least an opposite platform doppler frequency;

(e) transmitting said radio frequency signal in the original platform direction;

(f) receiving a third return signal;

(g) filtering said third return signal to isolate a true roadway reflected signal by steering steerable filter means to an appropriate frequency response using said opposite platform doppler frequency;

(h) processing said true roadway reflected signal to derive;

(1) a true platform speed with respect to said roadway; and

(2) a non-reverse platform direction of motion parameter with respect to said roadway;

(i) isolating a target reflected signal from said third return signal;

(j) processing said target reflected signal to derive;

(1) a target range with respect to said platform vehicle;

(2) a relative target speed with respect to said platform vehicle; and

(3) a target direction parameter with respect to said platform vehicle;

(k) mathematically combining said relative target speed and said true platform speed in a manner determined by the relationship of said non-reverse platform direction parameter and said target direction parameter to derive an absolute target speed with respect to said roadway;

(l) displaying said true platform speed, said absolute target speed, and said target range in selected dimensional units; and

(m) displaying an indication of said target direction parameter.

22. An apparatus for remotely determining the speed, range, and relative direction of movement of a moving target comprising:

(a) a radio frequency transceiver operative to transmit a substantially continuous radio frequency signal periodically shifted between a first frequency and a second frequency toward a moving target, to receive target reflected signals related to said first and second frequencies, and to convert said target reflected signals related to said first and second frequencies respectively to a first doppler signal and a second doppler signal;

(b) phase angle means receiving said doppler signals and operative to measure the phase angle between said first and second doppler signals, said phase angle means including;

(1) clock circuit means generating clock pulses;

(2) range pulse isolation means receiving said first and second doppler signals and digitally combining same to isolate a range pulse having a pulse width proportional to said phase angle;

(3) range gate means connected to said range pulse isolation means, receiving said range pulse, and using said range pulse to gate a number of said clock pulses proportional to said pulse width; and

(4) range counter means connected between said range gate means and said controller means, said range counter means counting the gated clock pulses resulting in said phase magnitude count;

(c) doppler frequency means receiving one of said doppler signals and operative to measure the doppler frequency of said one of said doppler signals;

(d) target direction means receiving said doppler signals and operative to detect the phase lead/lag relationship between said first and second doppler signals;

(e) controller means receiving signals representing said phase angle, said doppler frequency, and said phase relationship;

said controller means scaling said phase angle to a target range and said doppler frequency to a target speed and converting said phase relationship to a relative target direction; and

(f) display means connected to said controller means and displaying said target range and said target speed in selected dimensional units and indicating said relative target direction.

23. An apparatus for remotely determining the speed, range, and relative direction of movement of a moving target comprising:

(a) a radio frequency transceiver operative to transmit a substantially continuous radio frequency signal periodically shifted between a first frequency and a second frequency toward a moving target, to receive target reflected signals related to said first and second frequencies, and to convert said target reflected signals related to said first and second frequencies respectively to a first doppler signal and a second doppler signal;

(b) phase angle means receiving said doppler signals and operative to measure the phase angle between said first and second doppler signals;

(c) doppler frequency means receiving one of said doppler signals and operative to measure the doppler frequency of said one of said doppler signals;

(d) said doppler frequency including target speed means receiving said one of said doppler signals and generating a doppler counter which is the count of the pulses of said doppler signal over a measured period of time, said target speed being computed from said doppler count and the length of said period of time;

(e) clock circuit means generating clock pulses;

(f) window counter means operative to count said clock pulses to derive a window count to thereby measure said length of said period of time;

(g) window gate means connected between said clock circuit means and said window counter means, said window gate means being controllable to gate said clock pulses to said window counter means;

(h) doppler counter means operative to count the pulses of said one of said doppler signals to derive a doppler count;

(i) doppler gate means connected to said doppler counter means, said doppler gate means being controllable to gate said one of said doppler signals to said doppler counter means;

(j) window control means operatively connected to said controller means, said window gate means, and said doppler gate means, said window control means simultaneously controlling said window gate means and said doppler gate means to begin gating said respective pulses at the beginning of a doppler pulse, enabling said winow gate means and said doppler gate means to stop gating said respective pulses when either said window counter has reached a selected terminal window count or said doppler counter has reached a selected terminal dopper count, and controlling said window gate means and said doppler gate means to stop gating said respective pulses at the beginning of a doppler pulse;

said controller means computing said target speed from said window count and said doppler count;

(k) target direction means receiving said doppler signals and operative to detect the phase lead/lag relationship between said first and second doppler signals;

(l) controller means receiving signals representing said phase angle, said doppler frequency, and said phase relationship;

said controller means scaling said phase angle to a target range and said doppler frequency to a target speed and converting said phase relationship to a relative target direction; and

(m) display means connected to said controller means and displaying said target range and said target speed in selected dimensional unit and indicating said relative target direction.

24. An apparatus for remotely determining the speed, range and relative direction of movement of a moving target comprising:

(a) a radio frequency transceiver operative to transmit a substantially continuous radio frequency signal periodically shifted between a first frequency and a second frequency toward a moving target, to receive target reflected signals related to said first and second frequencies, and to convert said target reflected signals related to said first and second frequencies respectively to a first doppler signal and a second doppler signal;

(b) phase angle means receiving said doppler signals and operative to measure the phase angle between said first and second doppler signals;

(c) doppler frequency means receiving one of said doppler signals and operative to measure the doppler frequency of said one of said doppler signals;

(d) target direction means receiving said doppler signals and operative to detect the phase lead/lag relationship between said first and second doppler signals;

(e) said target direction means including direction counter means receiving said first and seocnd doppler signals and generating a direction count related to said phase relationship between said doppler signals, said direction counter being related to a target relative direction of movement of said target with respect to said transceiver;

(f) direction control means receiving said first and second doppler signals and generating a direction control signal having a first logic level if said first doppler signal leads said second doppler signal in phase and a complementary second logic level if said second doppler signal leads said first doppler signal in phase;

(g) up/down direction counter means having said direction control means connected to an up/down control input and receiving one of said doppler signals at a clock input, said direction counter means counting the pulses of said one of said doppler signals over a selected period of time resulting in said direction count, said direction counter over said selected period of time indicating whether said target is approaching or moving away from said transceiver;

(h) controller means receiving signals representing said phase angle, said doppler frequency, and said phase relationship;

said controller means scaling said phase angle to a target range and said doppler frequency to a target speed and converting said phase relationship to a relative target direction; and

(i) display means connected to said controller means and displaying said target range and said target speed in selected dimensional units and indicating said relative target direction.

25. An apparatus for remotely determining the speed, range, and relative direction of movement of a moving target comprising:

(a) transmitter means positioned in a platform vehicle and including transmitter structure transmitting a radio frequency signal periodically shifted between a first frequency and a second frequency toward a moving target;

(b) receiver means positioned in said platform vehicle and including a receiver structure receiving a return signal including a roadway reflected signal component which is said radio frequency signal as reflected from objects on a roadway on which said platform vehicle is moving and a target reflected signal component which is said radio frequency signal as reflected from said target and to convert said return signal to first and second doppler signals related respectively to said first and second frequencies;

(c) platform filter means receiving said first and second doppler signals and separating therefrom a first platform doppler signal related to said first frequency and a second platform doppler signal related to said second frequency;

(d) target filter means receiving said first and second doppler signals and separating therefrom a first target doppler signal related to said first frequency and a second target doppler signal related to said second frequency;

(e) platform speed means connected to said platform filter means and measuring a platform doppler frequency of one of said platform doppler signals;

(f) platform direction means connected to said platform filter means and detecting the platform phase lead/lag relationship between said first and second platform doppler signals;

(g) target parameter means connected to said target filter means and deriving from said target doppler signals a target phase angle and a target phase lead/lag relationship between said first and second target doppler signals and a target doppler frequency of one of said target doppler signals;

(h) controller means receiving signals representing said platform doppler frequency, said platform phase relationships, said target phase angle, said target doppler frequency, and said target phase relationship;

said controller means scaling said platform and target doppler frequencies respectively to a platform speed and a target relative speed, scaling said target phase angle to a target range, and converting said platform and target phase relationships respectively to a platform direction and a target direction;

on said controller means mathematically combining said platform speed and said target relative speed in a manner determined by the relationship between said platform direction and said target direction resulting in a target absolute speed; and

(i) display means connected to said controller means and displaying said platform speed, said target range, said target absolute speed in selected dimensional units and displaying an indication of said target direction.

26. An apparatus as set forth in claim 25 wherein

(a) said platform speed means includes a platform doppler counter receiving one of said platform doppler signals and generating a platform doppler count which is the count of the pulses of said one platform doppler signal over a period of time, said platform speed being computed from said platform doppler count and the length of said period of time;

and

(b) said platform direction means includes a platform direction counter receiving said first and second platform doppler signals and generating a platform direction count related to said platform phase relationship, said platform direction count being related to a relative direction of movement of said platform vehicle with respect to said roadway.

27. An apparatus as set forth in claim 25 wherein:

(a) said transmitter means and said receiver means comprise a forward transceiver means positioned to transmit said radio frequency signal in a forward direction of said platform vehicle;

(b) said apparatus includes a rear transceiver means substantially similar to said forward transceiver means and positioned to transmit said radio frequency signal in a rear direction of said platform vehicle; and

(c) said apparatus includes transceiver switch means operatively interconnected between said forward and rear transceiver means and said filter means and selectively operable to provide said first and second doppler signals from one of said transceiver means to said filter means.

28. An apparatus as set forth in claim 25 wherein:

(a) said platform filter means includes a pair of platform bandpass filter means; and

(b) said target filter means includes;

(1) a pair of low pass target filter means; and

(2) a pair of high pass target filter means; and

(c) said apparatus includes target filter selection means connected to said low pass filter means and said high pass filter means and operable to select the target doppler signals from one of said pairs of target filter means.

29. A method of remotely determining the speed, range, and relative direction of movement of a moving target comprising the steps of:

(a) transmitting a radio frequency signal toward a moving target;

(b) receiving a target reflected siganl which is said radio frequency signal as reflected from said target;

(c) processing said target reflected signal to derive a target range;

(d) processing said target reflected signal to derive a target speed;

(e) processing said target reflected signal to determine a period of said target reflected signal, and vertifying the consistency of said period independent of amplitude;

(f) processing said target reflected signal to derive a relative target direction;

(g) displaying said target speed and said target range after verifying said consistency of said period of said target reflected signal in selected dimensional units; and

(h) displaying an indication of said relative target direction.

30. A method of remotely determining the speed, range, and relative direction of movement of a moving target comprising the steps of:

(a) transmitting a radio frequency signal from a moving platform vehicle toward a moving target;

(b) receiving a return signal on said platform vehicle, said return signal including a roadway reflected signal component which is said radio frequency signal as reflected from stationary objects along a roadway on which said platform vehicle is moving and a target reflected signal component which is said radio frequency signal as reflected from said target;

(c) isolating a roadway reflected signal and a target reflected signal from said return signal;

(d) processing said roadway reflected signal to derive a platform speed with respect to said roadway;

(e) processing said target reflected signal to derive;

(1) a target range with respect to said platform vehicle;

(2) a relative target speed with respect to said platform vehicle; and

(3) a target direction with respect to said platform vehicle;

(f) mathematically combining said relative target speed and said platform speed in a manner determined by the relationship of said target direction to derive an absolute target speed with respect to said roadway;

(g) displaying said platform speed, said absolute target speed, and said target range in selected dimensional units; and

(h) displaying an indication of said target direction.

31. A method of remotely determining the speed and range of a moving target from a moving platform and comprising the steps of:

(a) substantially continuously transmitting a radio frequency signal toward a moving target;

(b) receiving a composite reflected signal which is said radio frequency signal as reflected from said moving target and a roadway reflected signal which is said radio frequency signal as reflected from stationary objects along a roadway on which said moving platform is traveling;

(c) processing said roadway reflected signal to derive a platform vehicle speed;

(d) processing said target reflected signal to derive a relative target speed which is the speed of said target relative to said platform vehicle;

(e) processing said target reflected signal to derive a target range;

(f) mathematically combining said relative target speed and said platform speed to derive a target absolute speed; and

(g) displaying said target absolute speed as said target speed and displaying said target range.

32. A method of remotely determining the speed, range, and relative direction of movement of a moving target comprising the steps of:

(a) transmitting a radio frequency signal toward a moving target;

(b) receiving a target reflected signal which is said radio frequency signal as reflected from said target;

(c) periodically alternating the frequency of said radio frequency signal between a first frequency and a second frequency;

(d) converting a first component of said target reflected signal which is related to said first frequency to a first doppler signal;

(e) converting a second component of said target reflected signal which is related to said second frequency to a second doppler signal;

(f) measuring the phase angle of the phase difference between said first and second doppler signals;

(g) scaling said phase angle to derive a target range;

(h) alternating the frequency of said radio frequency signal between said first and second frequencies if said target range is greater than a selected range;

(i) alternating the frequency of said radio frequency signal between a third frequency and a fourth frequency if said target range is not greater than said selected range;

(j) processing said target reflected signal to derive a target speed;

(k) processing said target reflected signal to derive a relative target direction;

(l) displaying said target range and said target speed in selected dimensional units; and

(m) displaying an indication of said relative target direction.

33. A method of remotely determining the speed, range and direction of a moving target from a moving platform and comprising the steps of:

(a) transmitting a radio frequency signal toward a moving target;

(b) receiving a composite reflected signal which is said radio frequency signal as reflected from said moving target and a roadway reflected signal which is said radio frequency signal as reflected from stationary objects along a roadway on which said moving platform is traveling;

(c) processing said roadway reflected signal to derive a platform vehicle speed;

(d) processing said roadway reflected signal to derive a platform vehicle direction;

(e) processing said target reflected signal to derive a relative target speed which is the speed of said target relative to said platform vehicle;

(f) processing said target reflected signal to derive a relative target direction;

(g) mathematically combining said relative target speed and said platform speed in a manner determined by the relationship of said target direction and said platform direction to derive a target absolute speed;

(h) processing said target reflected signal to derive a target range;

(i) displaying said target range and said target speed in selected dimensional units; and

(j) displaying an indication of said relative target direction.