JP4760123B2 - Radar equipment - Google Patents

Description

  The present invention relates to a radar apparatus, and more particularly to a radar apparatus that transmits a measurement signal based on a PN code.

  Conventionally, for example, a vehicle is equipped with a laser radar device in order to measure the distance from other vehicles in the vicinity. An example thereof is disclosed in Patent Document 1. The device disclosed in Patent Document 1 acquires time information common to both using GPS, and changes transmission timing based on the acquired time information when interference with other vehicles occurs. The TDMA method is used to make adjustments.

JP-A-9-159664

  However, the laser radar device in the above conventional example is equipped with a GPS receiver and requires processing using such information, which may cause a problem that the configuration of the in-vehicle system becomes complicated and the cost increases. .

  In addition, since the TDMA method is used as described above, it is difficult to secure a large number of simultaneous connections, and it is necessary to set a sufficiently wide transmission interval if necessary. Therefore, it takes a long time to measure, and there may arise a problem that it is difficult to monitor other vehicles and obstacles existing around the vehicle, particularly in other directions such as all directions.

  Therefore, an object of the present invention is to provide a laser device that can improve the disadvantages of the above-described conventional example, particularly suppress interference with others and reduce costs.

Therefore, a radar apparatus according to an aspect of the present invention is
A radar that includes a transmission control unit that controls transmission of a measurement signal under transmission conditions based on a predetermined PN code, and an output unit that transmits the measurement signal, and transmits the measurement signal so that it can be distinguished from other signals. A device,
A transmission condition setting means for randomly setting a transmission condition of the measurement signal is provided.

  According to the above invention, the measurement signal is transmitted from the output means under the PN code pattern set at random and the transmission conditions based on the PN code. Such a signal is used for measurement or the like. As described above, since the transmission conditions are set at random, it is possible to suppress the transmission conditions that are the same as the measurement signals used by others and to effectively suppress the interference of the measurement signals. Therefore, individual adjustment when using such measurement is unnecessary, and all can be produced with the same configuration, so that productivity can be improved and costs can be reduced.

  Further, the transmission condition setting means sets the transmission condition by setting a PN code. Further, the transmission condition setting means is characterized in that the transmission condition is set by setting a repetition period of a measurement signal transmitted based on a specific PN code. At this time, the transmission condition setting means is characterized in that the transmission condition is set by setting another PN code after the transmission control means transmits the measurement signal by the number of times set in the repetition cycle. . Furthermore, the transmission condition setting means is characterized in that the transmission condition is set by setting the transmission cycle of the measurement signal. At this time, the set transmission period is set so as not to be an integral multiple of other transmission periods.

  In this way, a large number of measurements can be made by randomly setting the transmission conditions of the measurement signal, such as the PN code that is the pattern for outputting the measurement signal, the repetition period of the PN code pattern, and the transmission period. It is possible to set a transmission pattern of a signal for use, and to suppress interference with other persons. In particular, by combining these and setting each at random, there is no need to increase the code length of the PN code, the pattern can be increased, and interference can be suppressed more effectively.

  The transmission condition setting means includes a counter having a plurality of bits whose values change at a predetermined cycle, and sets a transmission condition of the measurement signal based on a counter value determined at a predetermined timing. It is characterized by having. At this time, the transmission condition setting means sets the transmission condition of the measurement signal according to the value of the bit designated in advance of the counter. Thus, by using a counter composed of a plurality of bits, random transmission conditions can be easily set, and the configuration becomes easy.

  Further, the counter is characterized in that it has a function of determining a value of the counter that is changing by detecting a predetermined operation on an object equipped with the radar device. Further, it is desirable that the counter has a function of starting a change in the value of the counter by detecting a predetermined operation on the object equipped with the radar apparatus. It is more desirable that it is 1 [msec] or less. For example, the radar device is provided in a vehicle, and the counter has a function of detecting a key position of the vehicle and determining a value of the counter that changes in accordance with the detected key position. More specifically, the counter is characterized in that the key position of the vehicle starts changing the value of the counter at the energized position and has a function of determining the value of the counter at the engine start position.

  Thereby, the change of the counter is started by a human operation on the object equipped with the radar apparatus, and then the counter value is determined by a further different human operation. Therefore, the counter value, that is, the transmission condition can be set more randomly, and interference of the measurement signal can be effectively suppressed.

In addition, a control device for a radar device according to another aspect of the present invention is
A radar apparatus control device for controlling the operation of a radar apparatus having an output means for transmitting a measurement signal,
Transmission control means for performing transmission control of the measurement signal under transmission conditions based on a predetermined PN code;
A transmission condition setting means for setting a transmission condition by randomly setting at least one of a PN code, a repetition period of a measurement signal transmitted based on a specific PN code, and a transmission period of a measurement signal;
It is characterized by having.

Further, a radar apparatus control program according to another embodiment of the present invention is provided:
In a radar apparatus control device for controlling the operation of a radar apparatus having an output means for transmitting a measurement signal,
Transmission control means for performing transmission control of the measurement signal under transmission conditions based on a predetermined PN code;
A transmission condition setting means for setting a transmission condition by randomly setting at least one of a PN code, a repetition period of a measurement signal transmitted based on a specific PN code, and a transmission period of a measurement signal; A configuration for realizing this is adopted.

Furthermore, a transmission condition setting method for a radar apparatus according to another aspect of the present invention is as follows:
A method for setting a transmission condition in a radar apparatus comprising: an output means for transmitting a measurement signal; and a transmission control means for controlling transmission of the measurement signal under a transmission condition based on a predetermined PN code,
The transmission condition is set by randomly setting at least one of a PN code, a measurement signal repetition period transmitted based on a specific PN code, and a measurement signal transmission period.

  Even the control device, program, and method having the above-described configuration operate in the same manner as the above-described radar device, and therefore, the object of the present invention can be achieved.

  Since the present invention is configured and functions as described above, according to this, by setting the transmission conditions at random, it is possible to suppress the measurement pattern from being the same as the measurement signal used by another person, and to perform measurement. Therefore, it is possible to effectively suppress the interference of the signal for use, and therefore, no individual adjustment is required when using such measurement, and all can be produced with the same configuration, thereby improving productivity and reducing cost. It has an unprecedented excellent effect that can be achieved.

  The radar apparatus according to the present invention transmits a measurement signal so that it can be distinguished from other signals by performing spread spectrum modulation using a specific PN (Pseudo Noise) code and transmitting the measurement signal. It is a device that performs. In particular, the present invention is characterized in that the transmission conditions of the measurement signal such as the PN code to be used, the repetition period of the set PN code, and the transmission period are set at random. Hereinafter, a case where the radar apparatus is mounted on a vehicle and used to measure the presence (distance) of other vehicles present in the vicinity will be described. However, the radar apparatus of the present invention is not limited to such a usage method.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a functional block diagram showing the overall configuration of the radar apparatus. FIG. 2 is an explanatory diagram for explaining the counter value. 3 to 4 are functional block diagrams showing a detailed configuration of a part of the radar apparatus. 5 to 7 are flowcharts showing the operation of the radar apparatus. 8 to 10 are explanatory views showing the state of the laser device.

[Constitution]
The configuration of the radar apparatus will be described with reference to FIGS. As shown in FIG. 1, the radar apparatus includes a basic configuration unit 1, a transmission condition change unit 2, and a code allocation / measurement cycle determination unit 3.

First, the basic configuration unit 1 includes a short pulse generator 1a, a PN code generator 1b, an LD driver / measurement direction selector 1c, and an LD (Laser Diode) group 1d. The pulse signal generated from the short pulse generator 1a is subjected to spread spectrum conversion using a specific PN code by the PN code generator 1b, and the LD selected by the LD driver / measurement direction selector 1c according to the pattern of this PN code. A specific LD in the group 1d (laser diode) is caused to emit light. Therefore, the short pulse generator 1a, the PN code generator 1b, and the LD driver / measurement direction selector 1c function as transmission control means for performing transmission control of the pulse signal as a measurement signal based on the PN code. Yes.

  The light projecting means (output means) that actually transmits a pulse laser that is a measurement signal to the outside is configured by the LD group 1d including the six LDs described above. The LD is configured to be able to scan the measurement area without using a mechanical mechanism by switching on and turning on the LD driver 1C. However, only one LD may be used, and the LD itself may be movable, or a movable mirror (such as a galvanometer mirror) may be used.

Here, as the PN code, it is desirable to use an OOC (Optical Orthogonal Code) sequence. The advantage is that this OOC sequence is a code sequence for optical communication and is expressed in two states, ON or OFF. Even if a long code sequence is used, the number of times of ON is small, so the frequency of use of the light source is reduced, which is effective for life and energy saving. On the other hand, many other code sequences are mainly suitable for radio waves, and are represented in a plus / minus state and zero when there is no signal. Therefore, when applied to optical communication, the no signal and the negative signal are the same, which may cause a problem that the discrimination performance is degraded. However, by devising such as using a phase, it is possible to be used in other sequences, not necessarily limited to the use of OOC series as PN code.

  Next, the code allocation / measurement cycle determination unit 3 will be described. As shown in FIG. 1, the code allocation / measurement cycle determination unit 3 includes a counter clock 3 a, a counter 3 b, and a counter start / stop unit 4.

  The counter 3b is an 8-bit counter that sequentially rotates “0” and “1” at the rotation speed of the counter clock 3a. The counter clock 3a is a clock having a frequency of 0.1 msec or more than the counter 3b by one turn or more (2.5 MHz or more for an 8-bit counter). The counter start / stop unit 4 gives start and stop timings.

  As the start and stop timings, in this embodiment, the randomness of human operation is used as will be described later. This is because the human reaction speed is generally about 150 msec, and the ball speed thrown by a leading baseball player is 160 km / h or less. (From about 44 m / s to 0.2 msec per cm) is considered the limit. Therefore, as described above, if it is assumed that the counter 3b is a clock exceeding one turn at 0.1 msec, it is impossible for a human to control the stop timing. As a result, the value of the counter 3b can be determined at random, and the measurement signal transmission conditions can be set at random, as will be described later.

  In the present embodiment, key ignition is used as an example of the counter start / stop unit 4 that starts and stops the counter 3b. Specifically, it is preferable that the counter is started when the key position is ACC 4a when the vehicle is first energized, and is stopped when the vehicle is IGON 4b when the vehicle is in the engine starting state. Specifically, since the ignition switches ACC and IGON are connected to the junction block (J / B), the voltage changing at each position is detected by providing a comparator in the J / B. As a result, the ACC position or the IG_ON position is detected. In this way, it is possible to save energy (battery protection) by operating at ACC that does not require standby current, and at the key position close to this ACC, and by using IGON before and after engine start as stop timing. it can. However, the counter start / stop unit 4 is not limited to the one using the key position described above, and starts to change the counter value by detecting some operation on the object equipped with the radar device, or You may comprise so that the counter value which is changing may be determined. For example, as described above, when the vehicle is equipped with a radar device, keyless door unlocking, door opening, key insertion, D range, access ON, speed reaching 10 km / h or more (speed 5 km / h to A speed of 10 km / h) may be used as a start / stop signal depending on the time before and after the operation.

  Next, the value of the 8-bit counter 3b will be described in detail. For example, when (341,5,1), which is one type in the OOC sequence that is a PN code, is used, there are 17 types of PN code, so by using 4 bits of the 8-bit counter value, It is possible to assign 16 types of PN codes. Therefore, as shown in FIG. 2, bit numbers 0 to 3 are assigned as “code No.”. In addition, bit numbers 4 and 5 are assigned as four types of “measurement cycles” that are transmission cycles of measurement signals. Further, the remaining bit numbers 6 and 7 are assigned as “code switching period” which is a repetition period transmitted based on a specific PN code. The “PN code”, “measurement period”, and “code switching period” set by the bit value of the counter 3b can be conditions for transmitting a measurement signal, as will be described later. Therefore, the code allocation / measurement cycle determination unit 3 functions as a transmission condition setting means for setting transmission conditions at random by the counter 3b.

  Here, each said transmission condition is explained in full detail. First, “code No.” specified by 4 bits has two types of display patterns in which each bit is 0 or 1, and 2 types × 4 bits = 16 types such as 0000,0001,. PN code patterns can be displayed. Hereinafter, for example, these 16 types of patterns are represented as 0 to 9 and A to F, respectively.

  In addition, “measurement cycle” given 2 bits can display 2 types × 2 bits = 4 types of patterns such as 00,. These four types of patterns are assigned to four types of period measurement interval times, for example, 1 msec, 2 msec, 3 msec, and 4 msec.

  The “code switching period” is information for setting how many times the transmission using the 16 types of PN codes is repeated. Since this “code switching period” is given 2 bits, 2 types × 2 bits = 4 types of patterns can be displayed as 00,. These four types of patterns are assigned to cycles 1 to 4 as four types of code switching cycles. For example, when the code switching period is 1, each PN code is repeatedly transmitted once such as “123456789ABCDEF”, and when the code switching period is 2, each PN code is displayed as “112233345456678789AABCCDDEEF”. Is repeatedly sent twice. As described above, after measurement with a specific PN code pattern by repeating only the code switching period (times), the code No. Is incremented by 1, and the PN code is switched to perform measurement again. However, the PN code after switching is not necessarily the next code No. It is not limited to the PN code.

  Since the (341,5,1) OOC sequence described above has 17 types of codes, in this embodiment, if different codes are assigned to the respective radar devices provided on the left and right sides of the vehicle, the counter 3b The value is assigned to the code No. on the right side. (Nos. 1 to 16), and a count value +1 is assigned to the left side (Nos. 2 to 17).

  Thus, the code No. is determined by the value of the counter 3b. Only the combinations of 16 types + 1, 4 types of measurement intervals, and 4 types of code switching intervals have transmission conditions for measurement signals. As described above, when the counter clock 3a for setting the rotation period of the counter 3b is set to 28 MHz, the counter 3b is set to about 11 weeks at 0.1 msec. Therefore, the counter value is stopped by a human operation. Thus, the transmission condition based on the counter value can have sufficient randomness.

  Next, the transmission condition changing unit 2 will be described. The transmission condition changing unit 2 includes a measurement trigger generating unit 2a, a code switching unit 2b, and a measurement direction setting unit 2c. Then, as described above, the counter value determined by the code allocation / measurement cycle determination unit 3 is sent to the units 2a to 2c of the transmission condition change unit 2, and the transmission condition of the measurement signal is set. The structure of each part 2a-2c of the transmission condition change part 2 is further explained in full detail with reference to FIG. 3 thru | or FIG.

  FIG. 3 shows the code switching unit 2b. First, the code No. determined by the counter 3b of the code allocation / measurement cycle determination unit 3 is set. Is sent as the initial value of the code switching counter 2ba in the code switching unit 2b. The code No., which is the initial value, is used. Is sent to the PN code generator 1b of the basic component 1 described above, and the code NO. A measurement signal is transmitted using the PN code.

  Further, the code switching period determined by the counter 3b is sent to the comparator 2bc as a threshold value. When the measurement is started, a measurement trigger transmitted from a measurement trigger generation unit 2a described later is counted by a measurement number counter 2bb in the code switching unit 2b. The count value of the measurement number counter 2bb is sent to the comparator 2bc and compared with the comparator 2bc. When the threshold value (sign switching cycle) of the comparator matches the count value of the measurement number counter 2bb, a coincidence signal is output from the comparator 2bc to the sign switching counter 2ba. Then, in the code switching counter 2ba, by receiving the coincidence signal, the code switching counter value is incremented. Is switched. At the same time, a counter value reset signal is sent to the measurement number counter 2bb to reset the measurement number counter value. In this way, by repeating the above process, the code No. Measurements can be switched.

  Next, the measurement trigger generator 2a will be described in detail with reference to FIG. The measurement trigger generator 2a is equipped with a 28 MHz clock, and the frequency converter 2ab, which is a 15-bit counter, counts the clock, and the first comparator 2ad compares the counter value with a threshold value. Here, the threshold value in the measurement trigger generating unit 2a is a value that satisfies “28 MHz × threshold value = about 1 msec” transmitted from the threshold value switching unit 2ac. As a result, a measurement cycle clock of about 1 msec can be measured by the comparator 2ad, and a clock signal of 1 msec is output from the comparator 2ad to the measurement cycle counter 2ae.

The measurement cycle counter 2ae counts the clock output from the comparator 2ad and outputs this count value to the second comparator 2af. The “measurement cycle” determined by the counter 3b described above is transmitted to the second comparator 2af, and this measurement cycle is compared with the count value of the clock from the measurement cycle counter 2ae. . As a result of the comparison, and outputs a measurement trigger signal from the comparator 2af the short pulse generator 1a of the basic components 1 and code switching unit 2 b when they coincide. At the same time, the measurement cycle counter 2ae is reset. Thus, it is possible to generate a measurement trigger signal in accordance with the set measurement period (multiples of about 1 msec), and short pulse generator 1a, due code switching unit 2 b, as described above, the measurement cycle each A signal for measurement is transmitted to and the code is switched.

[Operation]
Next, the operation of the radar apparatus having the above configuration will be described with reference to FIGS. First, with reference to FIG. 5, description will be given of code allocation, measurement cycle, and code switching cycle determination operation. First, the user gets into the vehicle, inserts the key into the key cylinder, and twists the key. Then, when the key position is ACC, the 8-bit counter 3b starts to rotate (affirmative determination in step S1, step S2), and the counter stops when IG_ON (positive determination in step S3, step S4). Depending on the value of each bit of the counter value at this time, the initial code No. The measurement signal transmission conditions such as the measurement cycle and the code switching cycle are determined. Then, the counter value is output to the transmission condition changing unit 2 (step S5).

  Next, the PN code switching operation will be described with reference to FIG. First, when the vehicle is started and the system starts measuring operation, the initial code No. And the code switching period are set by the transmission condition changing unit 2, and a measurement signal is transmitted by the basic component 1 under such conditions, and measurement is started (step S11). Thereafter, every time measurement is performed, the count count is incremented by the code switching unit 2b of the transmission condition changing unit 2 (steps S12 and S13). If the value of the measurement number counter coincides with the code switching cycle (Yes in step S14), the code No. The counter is incremented and the sign for the next measurement is switched (step S15). Thereby, in the basic component 1, the PN code is switched and a measurement signal is output. Such an operation is repeated until the system such as the engine is turned off (step S16).

  Subsequently, an operation of performing measurement at the determined measurement cycle will be described with reference to FIG. First, the transmission cycle determined by the counter 3b is set by the transmission condition changing unit 2 (step S21). Then, the measurement cycle counter is started (step S22), and when the value of the measurement cycle counter coincides with the set measurement cycle (positive determination in step S23), a measurement trigger is output (step S24). Thereby, it is possible to perform measurement at every measurement cycle (for example, at intervals of 1 msec). At the time of measurement trigger output, the measurement cycle counter is reset to zero. Such an operation is repeated until the system such as the engine is turned off (step S25).

  By doing so, 256 types of measurement signal transmission patterns can be formed by an 8-bit counter. And, every time the vehicle is started, and every time the engine is started, a different transmission pattern is set at random, so that the possibility of matching the measurement signal itself used between the vehicles or the transmission timing becomes low, The occurrence of interference in the measurement signal can be effectively suppressed. In particular, an 8-bit counter can set three different transmission conditions, so even if you use an existing code system with more than a dozen types of PN codes, you can set various transmission conditions with a simple configuration. It becomes possible to do.

  In this embodiment, since the code switching period is set, even if the PN code pattern, the measurement period, and the like match, for example, as shown in FIG. Interference can be avoided by switching. Furthermore, in the present embodiment, even when the code switching periods coincide with each other, as shown in FIG. 9, the measurement periods are different (2 msec and 3 msec). Interference can be avoided during other measurements.

  In FIG. 10, the PN code and the measurement cycle are the same among a plurality of vehicles, but the number of times of code switching in each vehicle is different, and the state of interference at that time is shown as long-term (switching cycle). The result of the study is shown in (4). In this figure, 17 out of 64 crosstalks occurred between 4 vehicles (see the shaded area and arrow part in the figure), but interference can be avoided with a probability of 70% or more. I understand. Moreover, considering that the PN code matches the measurement cycle, the probability of interference can be quite low.

  From the above, according to the present embodiment, the transmission condition of the measurement signal, that is, the PN code used at the time of transmission, the measurement period, and the repetition period (code switching period) of the code of the same pattern are set at random. The transmission conditions that are the same as the measurement signals used by other persons are suppressed, and interference of the measurement signals can be effectively suppressed. Therefore, individual adjustment at the time of use for each laser device becomes unnecessary, and all can be produced with the same configuration, so that productivity can be improved and cost can be reduced. In particular, since it is possible to set a large number of measurement signal transmission patterns such as the number of combinations of each transmission condition, it is possible to suppress interference with other persons.

  Here, the case where the OOC sequence is used as the PN code is illustrated above, but the present invention is not limited to using such a code. The PN code used may be an M sequence, a GOLD sequence, or a Barker code. Furthermore, a code unique to each device such as a simple binary code may be used.

  In the above description, the case where the transmission condition is set with an 8-bit counter value is exemplified, but the transmission condition is not limited to such a value. For example, a counter having more bits may be used so that more types of measurement periods and code switching periods can be set.

  In the above description, the laser radar device mounted on the vehicle has been described. However, the radar device may be a radar device that uses radio waves (for example, microwaves), or may be used for a communication device.

  Next, a second embodiment of the present invention will be described. The radar apparatus according to the present embodiment has substantially the same configuration as that of the first embodiment. In addition, this embodiment is characterized in that the transmission period of the measurement signal is set so as not to be an integral multiple of other transmission periods. Details will be described below.

  First, for example, the measurement trigger generator 2a that actually determines the measurement cycle generates a clock for switching the cycle of about 1.2 msec by counting 15 bits of 28 MHz. Then, in the measurement period 1, measurement is performed every 1.2 msec using this 1.2 msec clock. Here, in the case of the first embodiment, the above 1.2 msec is simply multiplied by an integer such as 2, 3, 4 as the measurement period of the other measurement signals set as the measurement periods of 2, 3, 4. The period will be used. Specifically, in the case of the cycle 1, the second measurement is performed 1.2 msec after the first measurement, and then the third measurement is performed after 1.2 msec, that is, 2.4 msec after the first measurement. Is measured. In the case of cycle 2, the second measurement is performed after 1.2 × 2 = 2.4 msec after the first measurement, and interference with the third measurement of cycle 1 occurs. .

  On the other hand, in this embodiment, even if the period is 2 or more, the basic period set to an integral multiple as described above is not used. That is, a measurement cycle different from a multiple of 1.2 msec is set as another type of measurement cycle. For example, at a measurement distance of 50 m, the measurement ends at about 0.3 μsec + α, but the measurement timing difference from the period 1 at the next measurement is 0.3 μsec or more (here 0.5 μsec) as the measurement time. If it becomes, interference can be suppressed effectively. More specifically, in the case of period 1, since measurement is performed for about 0.5 μsec for each basic period, interference occurs when measurements in other periods overlap between basic period × integer + 0.5 μsec. It will be. Therefore, when the period is 2 or more, the measurement may be performed by shifting from the multiple of the basic period by the measurement time. That is, in the case of cycle 2, if the measurement is performed at an interval of (basic cycle × 2 ± 0.5 μsec), the number of interferences can be suppressed.

From the above, the basic period, that is, the clock period measured by the measurement period counter 2ae shown in FIG.
Clock cycle = ((reference cycle x multiple)-(one measurement time)) / multiple (equation 1)
The configuration can be realized by changing the threshold value using the threshold value switching unit 2ac and the first comparator 2ad shown in FIG.
Here, the above equation 1 is
Clock cycle = ((reference cycle x multiple) + (one measurement time)) / multiple (equation 2)
However, since the measurement time is extended, Equation 1 is desirable.

  Here, a specific basic period is set for each period and examined. For example, in period 1, 28 MHz is counted by 15 bits to be about 1.2 msec, and in period 2, a count number that is about 0.85 msec by the above formula, that is, 23611 is counted. Similarly, a different clock is generated by counting 28611 to be 1.03 msec in period 3 and counting 30000 to be 1.08 msec in period 4. As a result, when the same clock is used in cycle 1 and cycle 2, the one that was supposed to cause interference every time seen from cycle 2 is the use of a clock of 1.2 msec and 0.85 msec, respectively. Is measured every 1.2 msec, and every cycle is 0.85 msec × 2. Accordingly, interference occurs only at the least common multiple of 20.4 msec between 1.2 and 0.85, and the interference frequency can be further reduced.

  Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 11 is a block diagram illustrating the configuration of the radar apparatus according to the present embodiment.

  The radar apparatus according to this embodiment is equipped with a receiving system B in addition to the transmitting system A described in the first and second embodiments. Then, the receiver side system B is notified of the PN code randomly set by the transmitting side system A, which is a feature of the present invention, and the receiving side system uses the same PN code as when the measurement signal is transmitted. Thus, a predetermined measurement can be performed by despreading the received measurement signal. Hereinafter, each configuration will be described in detail.

  As shown in FIG. 11, the transmission-side system A has a configuration substantially similar to the configuration described in the first embodiment, and further, as a passive element to which an output value from the short pulse generator 1a is input. SAW-DLL 1e and a delay circuit 1f are provided. The function as the transmission side system A is as described above.

The receiving-side system B includes a photodiode 8 (PD) that receives a signal reflected from the measurement object, an amplifier 9 (bandpass filter; BPF) that amplifies and outputs the received signal from the photodiode 8, and signal discrimination. Part 6 and a synchronization acquisition part 7. The signal discriminating unit 6 further includes a SAW-DLL 6a as a passive element, a delay circuit 6b, a PN code generator 6c, and a PN code correlator 6d. The synchronization capturing unit 7 includes the SAW-DLL 6a, a time measuring unit 7a, and an arithmetic processing unit 7b. The transmission side system A and the reception side system B configured as described above operate as follows.

  First, the measurement signal transmitted from the laser diode 1d of the transmission side system A is reflected by the measurement object and propagates in the direction of the radar apparatus. Then, the photodiode 8 of the receiving system B receives the reflected signal. In the receiving system B, the received measurement signal is despread modulated. At this time, the PN code generator 6c of the receiving system B receives the code No. of the PN code used for the measurement signal. Is received from the PN code generator 1b of the transmitting side system A, and this makes it possible to demodulate the measurement signal properly received using the same PN code as the PN code used at the time of transmission. Become.

  Then, the time measurement unit 7a measures the time from when the measurement start trigger is received when the measurement signal is transmitted from the short pulse generator 1a of the transmission side system B to when the measurement signal is received, and the time data Is output to the arithmetic processing unit 7b. Thereafter, the arithmetic processing unit 7b calculates the distance from the radar device to the measurement object in the measurement space using the time data. Since the measurement method is known, the description thereof is omitted.

  The radar apparatus according to the present invention can be used as an apparatus that is mounted on a vehicle and detects the presence of an obstacle or another vehicle, and has industrial applicability.

It is a block diagram which shows the structure in Example 1 of this invention. It is explanatory drawing which shows the data structure of a counter value. It is a block diagram which shows the structure of a code | symbol switching part. It is a block diagram which shows the structure of a measurement trigger generation part. It is a flowchart which shows the operation | movement at the time of counter value determination. It is a flowchart which shows the operation | movement at the time of code | symbol switching. It is a flowchart which shows the operation | movement at the time of measurement based on a measurement period. It is explanatory drawing which shows the mode of the interference at the time of a measurement. It is explanatory drawing which shows the mode of the interference at the time of a measurement. It is explanatory drawing which shows the mode of the interference at the time of a measurement. It is a block diagram which shows the structure in Example 3 of this invention.

Explanation of symbols

1 Basic component (transmission control means)
2 Transmission condition change part (transmission control means)
3 Code assignment / measurement cycle determination unit (transmission condition setting means)
4 Counter start / stop unit 1a Short pulse generator 1b PN code generator 1c LD driver / measurement direction selector 1d Laser diode (output means)
2a Measurement trigger generator 2b Sign switching unit 2c Measurement direction setting unit 3a Counter clock 3b Counter

Claims (4)

A transmission control unit configured to transmit a measurement signal under transmission conditions based on a predetermined PN code; and an output unit configured to transmit the measurement signal so that the measurement signal can be distinguished from other signals using the PN code. A radar device for transmitting the measurement signal , provided in a vehicle;
A transmission condition setting means for randomly setting the transmission condition of the measurement signal by setting the PN code ;
The transmission condition setting means includes a counter composed of a plurality of bits whose value changes at a predetermined cycle, and sets the transmission condition of the measurement signal based on the value of the counter determined at a predetermined timing. Has function,
The counter has a function of detecting a key position of the vehicle and starting a change in the value of the counter at the energized position of the detected key position and determining a value of the counter at an engine start position.
Radar apparatus characterized by the above.   The time for the counter value to make one round is 0.1 [msec] or less,
  The radar apparatus according to claim 1.   The transmission condition setting means sets the transmission condition by setting a repetition period of the measurement signal transmitted based on the specific PN code,
  And, after the transmission control means transmits the measurement signal by the number of times set in the repetition period, the transmission condition is set by setting another PN code.
  The radar apparatus according to claim 1.   The transmission condition setting means sets the transmission condition by setting a transmission period of the measurement signal, and sets the transmission period so as not to be an integral multiple of other transmission periods.
  The radar apparatus according to claim 1.

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