A modular light detection and ranging system (1100; 1300; 1400; 1600; 1700) comprising: a) a first optical transmitter (1102; 1310-1324; 1406; 1906; 2008) comprising a plurality of first emitters, each of the plurality of first emitters being positioned to generate an optical beam with a field-of-view (1206, 1208; 1506-1512; 1814-1836) at a target range when energized; b) a second optical transmitter (1104; 1310-1324; 1406; 1908; 2010) comprising a plurality of second emitters, each of the plurality of second emitters being positioned to generate an optical beam with a field-of-view (1206, 1208; 1506-1512; 1814-1836) at the target range when energized, wherein the first and second optical transmitters (1102, 1104; 1310-1324; 1406; 1906, 1908; 2008, 2010) are positioned relative to each other so the fields-of-view of at least some of the optical beams generated by the first and second optical transmitter when energized overlap at the target range so as to provide a composite field-of-view, thereby providing continuous tracking of a target across the composite field-of-view at the target range; c) an optical receiver (1106; 1302-1306; 1408; 1902; 2004) comprising a plurality of optical detectors, a respective one of the plurality of optical detectors being positioned to detect a respective optical beam generated by at least one of the first and second optical transmitter (1102, 1104; 1310-1324; 1406; 1906, 1908; 2008, 2010) and reflected by the target in the composite field-of-view at the target range; and d) a controller (1108; 1326; 1410; 1614; 1702; 1938; 2002) comprising a first and second output being connected to respective control inputs of the first and second optical transmitters (1102, 1104; 1310-1324; 1406; 1906, 1908; 2008, 2010), and a third output being connected to a control input of the optical receiver (1106; 1302-1306; 1408; 1902; 2004), the controller being arranged to generate control signals at the first and second outputs that control energizing select ones of the plurality of first and the plurality of second emitters that generate optical beams with the fields-of-view that overlap at the target range so that only one of the plurality of first emitters and the plurality of second emitters generate an optical beam that when reflected off the target at the target range is detected by one of the optical detectors during a particular light detection and ranging measurement, and to generate a control signal at the third output that activates selected ones of the plurality of optical detectors to detect optical beams reflected from the target at the target range. a) a first optical transmitter (1102; 1310-1324; 1406; 1906; 2008) comprising a plurality of first emitters, each of the plurality of first emitters being positioned to generate an optical beam with a field-of-view (1206, 1208; 1506-1512; 1814-1836) at a target range when energized; b) a second optical transmitter (1104; 1310-1324; 1406; 1908; 2010) comprising a plurality of second emitters, each of the plurality of second emitters being positioned to generate an optical beam with a field-of-view (1206, 1208; 1506-1512; 1814-1836) at the target range when energized, wherein the first and second optical transmitters (1102, 1104; 1310-1324; 1406; 1906, 1908; 2008, 2010) are positioned relative to each other so the fields-of-view of at least some of the optical beams generated by the first and second optical transmitter when energized overlap at the target range so as to provide a composite field-of-view, thereby providing continuous tracking of a target across the composite field-of-view at the target range; c) an optical receiver (1106; 1302-1306; 1408; 1902; 2004) comprising a plurality of optical detectors, a respective one of the plurality of optical detectors being positioned to detect a respective optical beam generated by at least one of the first and second optical transmitter (1102, 1104; 1310-1324; 1406; 1906, 1908; 2008, 2010) and reflected by the target in the composite field-of-view at the target range; and d) a controller (1108; 1326; 1410; 1614; 1702; 1938; 2002) comprising a first and second output being connected to respective control inputs of the first and second optical transmitters (1102, 1104; 1310-1324; 1406; 1906, 1908; 2008, 2010), and a third output being connected to a control input of the optical receiver (1106; 1302-1306; 1408; 1902; 2004), the controller being arranged to generate control signals at the first and second outputs that control energizing select ones of the plurality of first and the plurality of second emitters that generate optical beams with the fields-of-view that overlap at the target range so that only one of the plurality of first emitters and the plurality of second emitters generate an optical beam that when reflected off the target at the target range is detected by one of the optical detectors during a particular light detection and ranging measurement, and to generate a control signal at the third output that activates selected ones of the plurality of optical detectors to detect optical beams reflected from the target at the target range.