WO2006067012A1

WO2006067012A1 - Method for expanding the detection range of a radar system and associated arrangement

Info

Publication number: WO2006067012A1
Application number: PCT/EP2005/056086
Authority: WO
Inventors: Jens Haensel
Original assignee: Robert Bosch Gmbh
Priority date: 2004-12-20
Filing date: 2005-11-21
Publication date: 2006-06-29
Also published as: EP1831719A1; DE102004061333A1

Abstract

The aim of the invention is to expand the detection range of a radar system for motor vehicles, wherein transmitter pulses (TX) and capture pulses (RX) are produced. The capture pulses (RX) are decelerated in relation to the transmitter pulses (TX) such that they are correspond to the running time of the capture pulses (TX) until the objects and back into the detection range. The capture pulses (RX) are added, respectively, to a fixed deceleration value when a maximum predetermined deceleration value for the detection range is achieved.

Description

Method for expanding the detection range of a radar system and arrangement

State of the art

The invention is based on a method for expanding the detection range of a radar system, in particular for use in motor vehicles. In radar systems for pulse operation pulse conditioning stages are in use, which generate so-called receive pulses in addition to the transmit pulses, which are delayed compared to the transmit pulses as it corresponds to the duration of the transmit pulses to objects in a detection area and back to the radar sensor. The radar pulses actually reflected on the objects (true receive pulses, in contrast to the so-called

Reception pulses) are fed to a mixer with the so-called receiving pulses. In coincidence, i. true received pulse, coincides at about the same time, i. within a time window, with the so-called received pulse, at least one object within the time window, which corresponds to a predetermined detection range, is detected in the down-converted baseband. This procedure has the

Advantage that objects, i. Radar targets are detected very reliably and false signals, e.g. Multiple reflections are effectively suppressed because they do not fall within the given time window.

Advantages of the invention

With the measures of claim 1, ie transmit pulses and receive pulses are generated, the receive pulses are delayed relative to the transmit pulses as it corresponds to the duration of the transmit pulses to objects in a detection range and back, upon reaching a maximum predetermined delay value for the Detection range are added to the receiving pulses each fixed delay values, the detection range of a given radar sensor can be extended with simple means without a pulse conditioning stage has to be redesigned or costly rebuilt.

Thus, for example, a pulse conditioning stage in the form of an ASIC, which was developed for the near range, detection range up to 20 m, be used for a medium reception range. It is then only necessary a delay device, which is controlled by the already existing control device for the ASIC in the signal path of the so-called receiving pulses is switched.

With the measures of claim 2 running time tolerances of the additionally connected in the signal path of the so-called receiving pulses delay device are compensated. As a result, the measurement accuracy in an extended detection range is not worse than in the detection range for which the pulse conditioning stage was originally designed. Claim 3 shows a low-effort arrangement for performing the method according to the invention.

The arrangement according to claim 4 allows a modular extension of the detection range and claim 5 has a simple control circuit to the object, which leads to an acceptable measurement accuracy of detected objects in an extended detection area.

drawings

Reference to the drawings embodiments of the invention will be explained in more detail.

FIG. 1 shows a block diagram for expanding the detection range;

Figure 2 shows a delay device with control circuit for extending the detection range and

FIG. 3 shows input and output signals of the delay device. Description of exemplary embodiments

FIG. 1 shows a radar system with a pulse conditioning stage VE for transmission (TX) and so-called reception pulses (RX). This pulse conditioning stage VE is implemented as an ASIC and is controlled by a microprocessor MP, i. that from the clock source of the

Microprocessor MP supplied clock signal CLK enters the ASIC. There, a delay between the transmit pulses TX and the so-called receive pulses RX is generated in accordance with the value predetermined by the microprocessor MP. For a detection range of 20 m, a repetition rate of e.g. 2.5 MHz selected. The time delay through the ASIC can be controlled by a control circuit in

Adjust the shape of the microprocessor MP in discrete small time steps and is set to a desired distance cell (detection range). For the distance cell, the delay time between transmit and so-called receive pulses is selected as corresponds to the transit time of the transmit pulses to objects in this receive cell and back to the radar sensor. The transmit and receive pulses are forwarded to the radar front end, where they control the corresponding transmit and receive switches TS and RS, the one hand, the signal of a microwave oscillator MO for the duration of the transmission pulses TX with the transmitting antenna AS and on the other hand for the duration of the so-called Receiving pulses RX connect via the receiving antenna AE with a receiver-side mixer RM. This mixer RM will also receive the true, i. the received pulses actually reflected on objects within a receiving cell. In coincidence, i. simultaneous arrival of the true receive pulses with the so-called receive pulses, appears at the mixer output a down-mixed baseband signal for further evaluation in an evaluation AW.

In the case of the maximum delay value that can be represented by the ASIC for a given detection range, a switch S1 is activated by the microprocessor MP and the initial value (delay 0) is simultaneously set in the ASIC.

The so-called received signal RX must now pass through a delay device FE with fixed delay value after activated switch S1 before it reaches the radar front end, or the receiving switch RS. As a result, the delay value of the so-called receive pulses RX now set in the ASIC is always added to a fixed delay value. If the delay time set in the delay device FE is equal to the maximum value that can be represented by the ASIC - A -

Delay time, thus can be a doubling of the

Reach detection range / measuring range. It is advantageous that the fixed delay time of the delay means FE has a constant value, since any fluctuations immediately reflected in the inaccuracy of the measurement.

To ensure this constancy, the circuit of Figure 2 can be used. This is a control that constantly compares the setpoint voltage UgoLL 'according to the delay time to be set with the current delay value. In a U / Δt block, the delay is generated, which can be continuously changed by a voltage. The control loop consisting of a Δt / U converter, which detects the deviation between the input and output signal of the delay device, and a comparison device in the form of an operational amplifier OPV, now counteracts fluctuations of the set delay value. This allows the required constancy of the fixed

Secure the delay over the automotive temperature range. By connecting several such fixed delay devices in series, the measuring range can in principle be extended in any desired modular manner.

Figure 3 shows input (IN) and output (OUT) of the delay device

FE. As can be seen from FIG. 3, an input pulse is delayed by Δt.

Claims

claims

1. A method for extending the detection range of a radar system, in particular for use in motor vehicles, comprising the following steps:

Transmission pulses (TX) and reception pulses (RX) are generated, the reception pulses (RX) being delayed with respect to the transmission pulses (TX) in the same way as the transit time of the transmission pulses to objects in a detection range and back, upon reaching a maximum predetermined delay value For the detection range, fixed delay values are added to the receive pulses (RX).

2. The method according to claim 1, characterized in that the fixed delay values are controlled in their constancy.

3. Arrangement for carrying out the method according to claim 1 or 2 with the following

Assemblies: a clock source (CLK), a controllable conditioning stage (VE) for the transmit (TX) and correspondingly delayed receive pulses (RX), - a control device (MP) for specifying the delay time between transmit and receive pulses, one of the control device ( MP) controllable switch (Sl), the at

Reaching the maximum predetermined delay value between transmit and

Receive pulses a delay device with fixed delay (FE) in the signal path of the receiving pulses (RX) switches whose fixed delay the Transit times of the transmission pulses to objects and back in an extended detection area corresponds.

4. Arrangement according to claim 3, characterized in that at least one further delay device (FE) in the signal path of the transmission pulses (RX) is switchable.

5. Arrangement according to claim 3 or 4, characterized in that a control circuit for the at least one delay device (FE) is provided which compares the desired value according to the delay time to be set with a current actual delay value and corrects deviations thereof.