A telemetry device that communicates with a receiving station, the telemetry device comprising: processing circuitry; and memory storing instructions that, when executed by the processing circuitry, cause the telemetry device to: receive, from a sensor, a range Doppler map 'RDM' value (510, 710) which is a power value in a binary floating point format, the RDM value comprising an exponent comprising bits, the RDM value comprising a mantissa comprising bits; convert the RDM value to a compressed RDM value in decibels 'dB', the compressed RDM value comprising a plurality of bits, wherein the processing circuitry is configured to: determine a first number based on a product of the exponent and a constant, wherein the constant is proportional to a logarithm of the number two; determine a second number using one or more bits of the mantissa as an index into a predetermined lookup table, wherein values of the lookup table are proportional to logarithms of candidate mantissa values; and determine the compressed RDM value based on rounding of a sum, wherein the sum includes the first and second numbers, wherein the rounding is based on a predetermined step size in dB; and transmit the compressed RDM value over a telemetry link to the receiving station, wherein: the constant used to determine the first number, the values of the lookup table, the compressed number and the step size are in decibels 'dB', the logarithm of the number two that is used to determine the first number is a base-10 logarithm, and the logarithms of the candidate mantissa values that are used to determine the second number are base-10 logarithms. processing circuitry; and memory storing instructions that, when executed by the processing circuitry, cause the telemetry device to: receive, from a sensor, a range Doppler map 'RDM' value (510, 710) which is a power value in a binary floating point format, the RDM value comprising an exponent comprising bits, the RDM value comprising a mantissa comprising bits; convert the RDM value to a compressed RDM value in decibels 'dB', the compressed RDM value comprising a plurality of bits, wherein the processing circuitry is configured to: determine a first number based on a product of the exponent and a constant, wherein the constant is proportional to a logarithm of the number two; determine a second number using one or more bits of the mantissa as an index into a predetermined lookup table, wherein values of the lookup table are proportional to logarithms of candidate mantissa values; and determine the compressed RDM value based on rounding of a sum, wherein the sum includes the first and second numbers, wherein the rounding is based on a predetermined step size in dB; and transmit the compressed RDM value over a telemetry link to the receiving station, wherein: the constant used to determine the first number, the values of the lookup table, the compressed number and the step size are in decibels 'dB', the logarithm of the number two that is used to determine the first number is a base-10 logarithm, and the logarithms of the candidate mantissa values that are used to determine the second number are base-10 logarithms. receive, from a sensor, a range Doppler map 'RDM' value (510, 710) which is a power value in a binary floating point format, the RDM value comprising an exponent comprising bits, the RDM value comprising a mantissa comprising bits; convert the RDM value to a compressed RDM value in decibels 'dB', the compressed RDM value comprising a plurality of bits, wherein the processing circuitry is configured to: determine a first number based on a product of the exponent and a constant, wherein the constant is proportional to a logarithm of the number two; determine a second number using one or more bits of the mantissa as an index into a predetermined lookup table, wherein values of the lookup table are proportional to logarithms of candidate mantissa values; and determine the compressed RDM value based on rounding of a sum, wherein the sum includes the first and second numbers, wherein the rounding is based on a predetermined step size in dB; and determine a first number based on a product of the exponent and a constant, wherein the constant is proportional to a logarithm of the number two; determine a second number using one or more bits of the mantissa as an index into a predetermined lookup table, wherein values of the lookup table are proportional to logarithms of candidate mantissa values; and determine the compressed RDM value based on rounding of a sum, wherein the sum includes the first and second numbers, wherein the rounding is based on a predetermined step size in dB; and transmit the compressed RDM value over a telemetry link to the receiving station, wherein: the constant used to determine the first number, the values of the lookup table, the compressed number and the step size are in decibels 'dB', the logarithm of the number two that is used to determine the first number is a base-10 logarithm, and the logarithms of the candidate mantissa values that are used to determine the second number are base-10 logarithms. the constant used to determine the first number, the values of the lookup table, the compressed number and the step size are in decibels 'dB', the logarithm of the number two that is used to determine the first number is a base-10 logarithm, and the logarithms of the candidate mantissa values that are used to determine the second number are base-10 logarithms.