Position determination in wireless communication systems

Method for determining mobile unit position in a wireless communication system, comprising the steps of:

• observing points of arrival time of signals between a number n of nodes and a mobile unit, where n≧2;
• obtaining pre-determined altitude data representing estimated altitude of said mobile unit as a function of lateral position;
• computing a lateral position of said mobile by numerically optimising relations having said points of arrival time as parameters;
• adding an altitude to said lateral position, giving a three-dimensional position, using said pre-determined altitude data associated with said computed lateral position.

Method for determining mobile unit position in a wireless communication system, comprising the steps of:

• determining a propagation time between a first node and a mobile unit using an initial signal and a response signal transferred forth and back between said first node and said mobile unit;
• observing points of arrival time of one-way signals between a number n of communication nodes and said mobile unit, where n>2, said communication nodes comprise said first node;
• obtaining pre-determined altitude data representing estimated altitude of said mobile unit as a function of lateral position;
• computing a position of said mobile by numerically optimising relations having said points of arrival lime and said propagation time as parameters using said pre-determined altitude data as constraints.

Node of a wireless communication system, comprising:

• receiver means, arranged for receiving data representing points of arrival time of signals between a number n of nodes of said wireless communication system and a mobile unit, where n>2;
• means for obtaining pre-determined altitude data representing estimated altitude of said mobile unit as a function of lateral position;
• and
• computing means, connected to said receiver means and said means for obtaining pre-determined altitude data, for computing a position of said mobile by numerically optimising relations having said points of arrival time as parameters using said pre-determined altitude data as constraints.

Node of a wireless communication system, comprising:

• receiver means, arranged for receiving a preliminary two-dimensional position of a mobile unit;
• means for obtaining pre-determined altitude data representing estimated altitude of said mobile unit as a function of lateral position;
• and
• correcting means, connected to said receiver means and said means for obtaining pre-determined altitude data, for computing a three-dimensional position of said mobile by numerically optimising relations having said two-dimensional position as parameters using said pre-determined altitude data as constraints.

Wireless communication system, comprising:

• a number n of nodes, where n≧2;
• a mobile unit;
• means for observing points of arrival time of signals between said nodes and said mobile unit;
• means for obtaining pre-determined altitude data representing estimated altitude of said mobile unit as a function of lateral position;
• computing means, connected to said means for observing points of arrival time and said means for obtaining pre-determined altitude data, for computing a position of said mobile by numerically optimising relations having said points of arrival time as parameters using said pre-determined altitude data as constraints.

Wireless communication system, comprising:

• a number n of nodes, where n≧2;
• a mobile unit;
• means for determining a propagation time between a first node and said mobile unit using an initial signal and a response signal transferred forth and back between said first node and said mobile unit;
• means for observing points of arrival time of signals between said nodes and said mobile unit;
• means for obtaining pre-determined altitude data representing estimated altitude of said mobile unit as a function of lateral position;
• computing means, connected to said means for observing points of arrival time and said means for obtaining pre-determined altitude data, for computing a position of said mobile by numerically optimising relations having said points of arrival time and said propagation time as parameters using said pre-determined altitude data as constraints.

Mobile unit arranged for allowing communication via a wireless communication system, comprising:

• means for observing points of arrival time of signals between a number n of nodes of said wireless communication system and said mobile unit, where n≧2;
• means for obtaining pre-determined altitude data representing estimated altitude of said mobile unit as a function of lateral position;
• and
• computing means, connected to said means for observing points of arrival time and said means for obtaining pre-determined altitude data, for computing a position of said mobile by numerically optimising relations having said points of arrival time as parameters using said pre-determined altitude data as constraints.