A method of operating a distance-measuring monitoring sensor for the detection and position determination of objects (12, 12a, 12b) in an at least two-dimensional protected field, wherein the monitoring sensor comprises at least one light transmitter which is configured to transmit light pulses into the protected field; at least one light receiver which is configured to receive light pulses as reception light pulses (22, 24) which are reflected or remitted by at least one object (12, 12a, 12b) possibly present in the protected field; and a deflection unit which is configured to periodically scan at least the protected field with the transmitted light pulses, wherein the respective position of the at least one object (12, 12a, 12b) can be determined from an angle of rotation of the deflection unit and from the distance determined in dependence on the time of flight of a respective reception light pulse, said method comprising the steps: a) detecting a respective detected signal (30, 32) which comprises a respective time curve of a reception signal received by the light receiver for a respective angle of rotation; b) determining the number of reception light pulses (22, 24) which are included in a respective detected signal (30, 32), with that reception light pulse (22, 24) which has the shortest time of flight representing a first reception light pulse and a possibly present reception light pulse (22, 24) which has a longer time of flight representing a second reception light pulse; and c) generating a detection signal for a respective detected object (12, 12a, 12b), with the detection signal comprising information on the determined position of the object (12, 12a, 12b), characterized in that the method comprises at least the three following test conditions and the determination of the position and the determination of the distance take place in dependence on a respective logical truth value of at least one of the test conditions, wherein - a check is made in accordance with a first test condition whether the number of reception light pulses (22, 24) in a respective reception signal is equal to 1; - a check is made in accordance with a second test condition whether a comparison object, whose associated reception light pulse (22, 24) has the same or at least substantially, i.e. within the framework of the measurement accuracy of the monitoring sensor, the same time of flight as the first reception light pulse, was detected for at least one adjacent angle of rotation; and - a check is made in accordance with a third test condition whether a reflector, whose associated reception light pulse (22, 24) has the same or at least substantially, i.e. within the framework of the measurement accuracy of the monitoring sensor, the same time of flight as the second reception light pulse, was detected for at least one adjacent angle of rotation, wherein the first test condition is checked in a first test step, either the second or third test condition is checked in a possibly performed second test step and the third or second test condition which has not been checked up to then is checked in a possibly performed third test step, and wherein the determination of the distance takes place on the basis of the time of flight determined for the second reception light pulse (22, 24) if the truth value of the first, second and third test conditions is FALSE in each case and otherwise takes place on the basis of the time of flight determined for the first reception light pulse (22, 24). a) detecting a respective detected signal (30, 32) which comprises a respective time curve of a reception signal received by the light receiver for a respective angle of rotation; b) determining the number of reception light pulses (22, 24) which are included in a respective detected signal (30, 32), with that reception light pulse (22, 24) which has the shortest time of flight representing a first reception light pulse and a possibly present reception light pulse (22, 24) which has a longer time of flight representing a second reception light pulse; and c) generating a detection signal for a respective detected object (12, 12a, 12b), with the detection signal comprising information on the determined position of the object (12, 12a, 12b), - a check is made in accordance with a first test condition whether the number of reception light pulses (22, 24) in a respective reception signal is equal to 1; - a check is made in accordance with a second test condition whether a comparison object, whose associated reception light pulse (22, 24) has the same or at least substantially, i.e. within the framework of the measurement accuracy of the monitoring sensor, the same time of flight as the first reception light pulse, was detected for at least one adjacent angle of rotation; and - a check is made in accordance with a third test condition whether a reflector, whose associated reception light pulse (22, 24) has the same or at least substantially, i.e. within the framework of the measurement accuracy of the monitoring sensor, the same time of flight as the second reception light pulse, was detected for at least one adjacent angle of rotation,