Abstract: An antenna unit is used in an antenna array. It comprises a measurement signal receiver for receiving and digitizing a measurement signal from an antenna. A time delay unit delays the digitized measurement signal. A data collection receiver receives a data collection frame, and a data collection transmitter is configured to sum the delayed digitized measurement signal with pre-existing data in the received data collection frame and to transmit the so constructed updated data collection frame further.

Abstract: An antenna unit is used in an antenna array. It comprises a measurement signal receiver for receiving and digitizing a measurement signal from an antenna. A time delay unit delays the digitized measurement signal. A data collection receiver receives a data collection frame, and a data collection transmitter is configured to sum the delayed digitized measurement signal with pre-existing data in the received data collection frame and to transmit the so constructed updated data collection frame further.

Abstract: A code for signal transmission is a so-called perfect code with zero sidelobes in its autocorrelation function if and only if the modulus of the Fourier transform of said code is equal to 1. A communication device equipped for communications with perfect codes is one, a code source of which outputs a perfect code. A remote sensing device equipped for remote sensing with perfect codes is one, a code source of which outputs a perfect code.

Abstract: Moving objects are detected with a radar by collecting samples of a received signal over an integration period. The terms of a match function contain a product of a sample of said received signal and a delayed-in-time, Doppler-shifted replica of a transmission and depend on parameters that describe an object that caused a reflection of the transmission. The most probable values of the parameters are found by maximizing the match function through Fourier transforming a vector consisting of terms of the match function. Those of said products that contain a non-zero contribution of said delayed-in-time, Doppler-shifted replica of a transmission are actually computed while the others of said products are zero Only non-zero blocks of the products count as final terms to the vector to be Fourier transformed that have nonzero value while intermittent blocks that have zero value are left out.

Abstract: Moving objects are detected with a radar by collecting samples of a received signal over an integration period. The terms of a match function contain a product of a sample of said received signal and a delayed-in-time, Doppler-shifted replica of a transmission and depend on parameters that describe an object that caused a reflection of the transmission. The most probable values of the parameters are found by maximizing the match function through Fourier transforming a vector consisting of terms of the match function. Those of said products that contain a non-zero contribution of said delayed-in-time, Doppler-shifted replica of a transmission are actually computed while the others of said products are zero Only non-zero blocks of the products count as final terms to the vector to be Fourier transformed that have nonzero value while intermittent blocks that have zero value are left out.

Abstract: Characteristics of a target are measured by a radar or sonar. Pulses (101, 102, 103) are transmitted and in between (X) the transmissions of pulses a signal is received which depends on the transmitted pulses and on the distribution of the characteristics measured at different ranges. The distribution at different ranges of the characteristics measured is determined by representing it by means of a substantially linear system of equations in which the variables are the values of the characteristics measured at desired ranges, and by solving the system of equations for the variables. The transmitted pulses form a cyclically repeated pulse code or a continuously changing pulse train.