Ground proximity warning system

An instrument for measuring altitude comprising:

• a trigger circuit, a selection circuit, a pulse generator, a detector circuit, a dividing circuit, a buffer, and a cockpit speaker;
• wherein the trigger circuit, the selection circuit, the pulse generator, the detector circuit, the dividing circuit, the buffer, and the cockpit speaker are electrically interconnected;
• wherein the instrument for measuring altitude is configured for use with a private aviation aircraft;
• wherein the private aviation aircraft further comprises landing gear and a cockpit;
• wherein the instrument for measuring altitude measures the altitude of the private aviation aircraft from a landing strip;
• wherein the instrument for measuring altitude measures the altitude of the private aviation aircraft within three meters of the landing strip;
• wherein the instrument for measuring altitude generates an audible series of clicks within the cockpit to indicate the altitude to a pilot;
• wherein a higher click frequency indicates a lower altitude;
• wherein the instrument for measuring altitude measures the altitude of the private aviation aircraft by measuring a reflected pulse from an ultrasonic pulse directed towards the landing strip;
• wherein the trigger circuit is a timing circuit;
• wherein the trigger circuit initiates an operation of the instrument for measuring altitude after deployment.